VISION FOR R & D IN PHYSICAL SCIENCES
Government of India
Ministry of Science & Technology
Department of Science & Technology
New Mehrauli Road
New Delhi – 110 016.
Condensed Matter Physics and Materials Science
High Energy Physics
Astronomy & Astrophysics
Lasers, Optics, Atomic & Molecular Physics
Some Common promotional needs of all areas in
The Department of Science & Technology has been promoting research in frontier and emerging areas through the Science & Engineering Research Council (SERC). SERC is composed of eminent scientists, professionals and technologists drawn from various universities, national laboratories and industries, and is assisted by a large number of Programme Advisory Committees (PACs) in various disciplines. SERC has evolved, over the years, a unique peer-review system which has been well-recognised by the scientific community. It has helped in promoting and strengthening several new areas of research and established a large number of national research facilities, core groups/centres. It has also endeavoured to strengthen the research capabilities of relatively small and less-endowed universities/departments to raise their research activities beyond the critical level.
The Council recently reviewed its activities and areas of research which were identified some time back and decided to undate those areas for future support. Under the overall supervision and guidance of the SERC, PACs in various disciplines were requested to prepare a state-of-the-art document called "Vision for R&D" reflecting new challenges for the scientific community, national facilities to be set up including new ways and mechanisms for their promotion.
Against this background are the Department of Science & Technology has decided to give wider publicity to these newly selected areas with a view to promote them in future. This document "Vision for R&D in Physical Sciences" is for those who are interested in vigorously pursuing research in Physical Sciences. It is hoped that this document would be useful to the scientific community in planning their future research activities.
As mentioned in the Preface, the task of identifying the new thrust of challenging areas, at the frontiers of Physical Sciences, was assigned to various Programme Advisory Committees. They were also requested to highlight the strategies to be adopted in raising the activities in the country in these chosen areas including establishment of new facilities and adoption of new management structures.
All the PACs contacted a large number of active workers in their area and organized special brain-storming meetings to arrive at the recommendations contained in the following pages. While there were some subject-specific recommendations, there were also some other recommendations which cut across various disciplines in Physical Sciences. We have listed the subject-specific recommendations first, followed by the general recommendations.
All PACs, at the very outset, have emphasized that any such listing of ‘thrust’ or ‘challenging’ areas should not in any way prejudice consideration of individual research proposals which should always be judged purely on their merit. Secondly, any attempt to identify narrow thrust areas could be self-defeating in case some dramatic and totally unexpected developments take place in that field (as for example happened with the discovery of high Tc Superconductivity).
In listing out the thrust areas, the following points have been kept in mind –
CONDENSED MATTER PHYSICS AND MATERIALS SCIENCE
There has been an explosion of activity in Condensed Matter and Materials Science in the last few decades. This area has emerged as a major source of basic phenomena, new devices and indeed much of physical science-based technology, present and future. This growth has been fuelled by discovery and development of new kinds of materials, unusual phenomena in them, novel instrumentation, and devices based on them. The field is interdisciplinary cutting across physics, chemistry, materials science, chemical engineering, electrical communication and device engineering etc. It is also rich in contributing basic ideas to a number of scientific and technological fields. Our investment in this broad field has been haphazard, subcritical in size and insufficient in quality.
The field of condensed matter physics/materials science needs a several fold increased in sustained support, for the following reasons :
The number of areas which fall under this broad umbrella is large. While any good proposal in any area of research needs to be supported, it was felt that one should focus on a few selected areas for which additional investment is specially required in the 9th plan period.
It will be impossible even to outline the current developments in research worldwide in condensed matter physics as this covers a wide area of activity. Here we will limit ourselves to some pointers which will influence the choice of thrust areas in this document.
In the area of soft condensed matter there are a few groups working in the country on a very limited set of systems and phenomena. These groups are in Indian Institute of Science and the Raman Research Institute in Bangalore, the IGCAR, Kalpakkam, BARC, Mumbai and in the University of Bhavnagar. Each group is small in size and is ill-equipped to carry out comprehensive studies. Still the groups have managed to develop some expertise and make some useful contributions. It is necessary to enlarge these groups and provide them with much needed facilities to be described below.
In the field of engineered quantum structures, there are a few groups with MOCVD/MBE equipment with the capability of making such systems in a very limited fashion. The work in this area is being done at TIFR, Mumbai, the Solid State Physics Laboratory at Delhi and at IISc., Bangalore. IIT, Chennai has a MBE unit with limited capabilities. However, the cost of maintaining these units is prohibitive and this prevents the optimal utilization of these units. There are not enough competent and trained technical staff to keep these units running. The amount of research work in this area is incommensurate with the importance of the subject and the size of our country.
Work on Kondo systems and heavy Fermion superconductors is mainly done at TIFR, Mumbai. Systematic work on electron tunneling and transport properties in some strongly correlated oxide systems has been done in IISc, Bangalore. However, single crystals of the intermetallics and oxide materials of the required quality is not being grown anywhere in this country. While many groups are working on high temperature superconductors, the work is mainly on transport and magnetic properties. In many cases, the experimental work lacks in quality. To understand the strongly correlated electron systems, comprehensive measurements including optical absorption and scattering, specific heat, magneto-resistance and Hall effect are also important and these measurements have to be done at low temperatures. It is therefore necessary to set up facilities of such studies at low temperatures and high magnetic fields.
Though a few groups have been studying conducting polymers in this country, there is no serious involvement of chemists in thinking up and making new kinds of systems. Only electrical transport measurements are being made on the conducting polymers. There is a need to study carrier generation and recombination induced by light pulses and the effect of blends on the electrical properties of these polymers. There are two or three groups working in molecular electronics. But the effort is minuscule.
The culture of experimentation, materials development and instrumentation is dying in the country and unless serious steps are taken immediately, there will be long-term damage to the health of basic and applied materials-based research as well as development.
There is considerable high level of activity in theoretical condensed matter physics in a few places in this country. Some of this activity overlaps and stimulates experiment. But the interaction between theory and experiment should be closer. The main bottleneck at present is poor infra-structure (computational, library and communication facilities, maintenance and running costs, and general support).
Research work will flourish only if motivated and bright students opt for research. Unfortunately, the quality of students coming out of the universities is not of the required standard. One reason for this may be that the faculty in universities are unable to involve themselves in fruitful research for lack of facilities and convey the excitement of research to the students. It is, therefore, important that new facilities should be located in universities and educational institutions where there is a constant influx of students. There is a necessity for the more-endowed institutions to interact with the faculty of the less-endowed universities and train them in research in frontier areas. This will have a multiplier effect in transplanting new research techniques in the universities.
Some of the thrust areas being recommended for special initiatives are as follows :
Soft Condensed Matter Physics
As mentioned in the section on the national scene, there is a necessity to strengthen the infrastructure for carrying out comprehensive experiments in this area. It is suggested that at least three experimental centres with all necessary facilities be developed in the next five years. These centres would be equipped with facilities such as high resolution X-ray diffractometer (rotating anode with two-dimensional detectors and small angle scattering facilities), viscometers, light scattering set up, imaging microscopes/video cameras, chemistry unit and dielectric measurement facilities.
Another essential need is access to world class synchrotron and neutron facilities in Japan, USA and Europe. This is mentioned separately below, since this need is common to most areas of condensed matter/materials science.
Strongly Correlated Systems (Oxides, Sulfides, Rare Earth and Actinide Intermetallics)
The main shortcomings in these area are : (i) absence of facilities for growing single crystals, (ii) absence of centres where comprehensive measurements can be made, (iii) total lack of certain kinds of facilities (optical property measurements, low temperature and high magnetic field facilities etc.), and (iv) the small scale of effort (lack of quality manpower). Considering all this, we suggest the following :
Conducting Polymer and Molecular Electronics
This is a field where chemists have to take the initiative in thinking up and making new kinds of systems and physicists have to explore their properties. Such composite groups will have to be identified or nucleated, and encouraged. Facilities for the growth, characterization and measurement are needed in several places.
Engineered Quantum Structures
There are 6 MBE units in the country of which three were procured for high temperature superconductivity research (one in IIT, Kharagpur, one in NPL, Delhi and one in BARC, Mumbai). Of the remaining MBE units, there is only one with limited capabilities for semiconductor research in an educational institution (IIT, Chennai). Of the MOCVDs, only one in IISc., Bangalore, is in an educational institution. Prohibitive running and maintenance costs prevent the optimal utilization of the existing units. It may be added that this area is intensive in capital, maintenance costs as well as technical support staff. Due to the technological importance of heterostructurs, it is felt that it is worthwhile to extend operational support to this area. The support will cover the cost of reconditioning and updating some of the existing facilities and providing the running cost and staff support for at least two machines in the next five years and for setting up two new dedicated machines.
Theoretical Condensed Matter Physics
As mentioned earlier, the main bottleneck at present is poor infrastructure (computational, library and communication facilities, maintenance and running costs, and general support). Some of the active groups need to be consolidated and the infrastructure enhanced. They should also play a more active role as national centres. Poor library facilities and paucity of quality information is actually a growing handicap cutting across disciplines.
Additional Support for Condensed Matter/Materials Research
in Project Mode
A great strength of condensed matter science is diversity and surprise. Also, a number of fields already active, need highly enhanced support. Examples of the last are ferroelectric thin films, nonlinear optical materials and magnetic systems. Much work in this area is substandard because of low level of support, poor quality manpower etc. We cannot become competitive or useful unless major support, with clear cut expectations and demands is forthcoming.
Access to International Facilities
There are only a few centres in the world with very high level facilities such as neutron beams, synchrotron X-ray sources for structure and photoemission etc. in Japan, Europe and USA. All areas of condensed matter science need them in a major way. Provision should be made for access to such laboratories, payment for beam time, instrumentation development etc.
Strategy to be Adopted
It is clear from the above write-up that the needs of difference areas are very different. For example, there is a need for setting up common expensive facilities such as low temperature high magnetic field facilities, characterization facilities such as HRTEM, Cryo TEM, which should be accessible to any group which may want to use them. In certain areas, individual groups will have to be nucleated and nurtured. So, one needs to have many-pronged strategy which will be adaptable to the specific situation.
We believe that the following three principles need to be followed if this initiative is to meet with success:
It is suggested that a Board of Scientists drawn from different disciplines in condensed matter physics/materials science be constituted under the DST umbrella and charged with the management of the initiative. This Board will decide on a number of questions, e.g., setting up common facilities which can be used by scientists working in different areas, as well as in allocation of funds in different areas for setting up specialized facilities useful in each area and for improving infrastructural facilities. An advisory committee of experts will be set up for each area. The committee for each area will recommend to the Board the nature of specialized facilities to be set up, the location of the facilities and the distribution of funds to the different groups to set up new experiments or to improve their infrastructural facilities. The advisory committee should also monitor the progress.
It is necessary to ensure that cumbersome bureaucratic procedures generally prevalent in all our institutions are circumvented by having a separate administrative cell to look after the needs of the centre. For success in competitive science, a flexible administration and quick decision-making are essential.
The international scene in the Plasma Science in general and Controlled Thermonuclear Fusion in particular has undergone a sea change since 1990. The holy goal of economic and cheap fusion power appears closer than ever before. The application of plasma based technologies to industry is continuously increasing and yielding fruitful dividends.
In the last decade several medium and large size tokamaks have appeared on the scene. A steady improvement in plasma performance in fusion relevant parameter space has been obtained. A few big tokamaks are poised for major leap forward. The Deuterium-Tritium operations in Tokamak Fusion Test Reactor (TFTR) at Princeton Plasma Physics Laboratory in USA started in 1994 and since then has been showing very encouraging results in terms of plasma b (the ratio of the plasma pressure to magnetic pressure), confinement of
a particles and the record value of the neutron yield. Very recently new regimes of Tokamak operations with negative shear and considerably improved plasma confinement have been discovered in DIII-D and TFTR tokamaks. The Joint European Torus (JET) at Culham, U.K. is poised for the break even which is a first step towards the economic viability of Fusion. In the area of fusion technology, the design of remote handling in D-T operation, Tritium inventory, blanket and first wall components are being actively investigated. The other area which is receiving increasing attention in tokamak research is the steady state operation. Several tokamaks with superconducting coils and auxiliary current drive and heating are being designed to study the plasma performance and behaviour of first wall component under steady state conditions. In the alternative steady state devices, Japan is building a large helical device (LHD), while the Wendelstein VII-A stellerator at Max Plank Institute at Garching, Germany is making steady progress.
Similar scenario exists in the Inertial Confinement Fusion (ICF) research. Experiments carried out at Lawrence Livermore Laboratory in USA on direct drive ICF targets using NOVA laser facility, the direct drive implosion experiments at the University of Rochester’s Laboratory for Laser Energetics and GEKKO II at Osaka University have yielded promising results. The program is getting a boost with sanction of National Ignition Facility in USA and upgradation of other facilities towards the achievement of ignition with the direct-drive fusion.
Plasma theory has continued to fascinate theoreticians and has been applied to a wide variety of processes in solar physics, magnetosphere, ionosphere, astrophysics besides the fusion physics. The complexities of the plasma problem has given rise to new modes of joint efforts and collaborations among scientists through formation of task forces etc. The problem of the plasma transport, for example, is being investigated in USA and Europe through various task forces. Rapid progress in computer technology and software engineering has made it possible to do realistic large scale simulations in 2 & 3 dimensional MHD processes. The new and young field of dusty plasma has now come to age. Over past five years several interesting processes like formation of dust crystals have been demonstrated in laboratory. A number of experiments have been conducted in different parts of the world to study the processes of charging of neutral grains in unmagnetised and magnetised plasma environment. Relevance of dusty plasma, processes in several planetary, interplanetary and galactic processes has been established. In the field of single species plasma, interesting set of experiments showing formation of vortex crystal, merger etc. have been conducted. The main thrust in this area seems to explore deeply the isomorphism between 2-d non-neutral plasma and parallel flow in hydrodynamics.
Plasma based technology, on the other hand, has made deep inroads in industrial applications. For instance, it is now fairly established that material processing using high energy content of thermal plasmas is efficient and economically viable. Plasma nitriding technology is being used for tool and surface hardening. Protective coatings and polishing using plasma techniques have been demonstrated and plasma based metallurgy is gaining ground.
In the field of plasma devices, new and efficient electrical switches using E x B plasma flows, and electron beams are being developed. Free electron lasers have attained higher levels of efficiency in terms of monochromaticity and control of radiation. Particle acceleration using strong electrical fields in the plasma has been experimentally demonstrated in UCLA, USA.
With the winding up of the Reversed Field Pinch experiment in TIFR in the late sixties, there was a lull in plasma physics activity in the country. Different groups picked up the threads again in the 1970’s. Activities in plasma physics in the country re-started with the Physical Research Laboratory establishing a basic plasma physics programme with strongly interacting theoretical and experimental elements. In BARC, both technologically oriented thermal plasma activities and experimental work in laser plasma interaction started around this period. In the Saha Institute of Nuclear Physics, the accelerator physics group also broadened their activity to cover basic experimental plasma physics. Work in the universities was primarily centred on theoretical work, although small groups interested in non-linear plasma physics and gaseous electronics existed.
The 1980’s saw major growth in national programmes. The PRL programme grew into the Institute for Plasma Research which established the Aditya tokamak and a broad based activity in basic plasma physics and development of core technologies relevant to fusion and applied plasma physics. The MHD programme at BARC was spun off into BHEL, with emphasis shifting into power generation. The Laser programme grew in terms of laser capability and the sophistication of diagnostics. SINP also established a tokamak experiment based on SINP – Tokamak, a amachine procured from Japan. IIT Delhi started experiments in beam and microwave-plasma interaction and collisional plasmas, while IIT Kanpur grew laser plasma and plasma chemistry activities.
This period also saw the institutionalisation of DST support to plasma physics with the setting up of the Programme Advisory Committee in Plasma Physics. With the active involvement of PAC, institute-university interaction grew. The Satellite Research Projects were established to nucleate and promote plasma physics activity in universities through a proactive mechanism of generation of research proposals and monitoring research progress. The Baroda and Santiniketan workshops helped in consolidating the emergence of a national community in plasma sciences.
The early part of 1990’s, namely the period 1991-95 again saw indications of growth, with the establishment of the research programme for the second generation fusion machine at IPR. This period also saw the beginning of the growth of cross disciplinary plasma science with programme on plasma assisted material processing and free electron laser beginning to be established. The BARC programme also developed more towards plasma processing, while the SINP activities grew in terms of upgrading the plasma parameters and technology. Strong inter-institutional programmes in fusion and plasma applications also grew. The SRP programme was effective in starting plasma-related research in many universities, again with a strong inter-disciplinary thrust.
Thus, at present, a broad-based plasma physics and applications programme has been established in the country, which has been primarily due to the thrust generated by the programmes of the Department of Science and Technology. DST has done a remarkable job of fostering ad promoting plasma science in the country during the past decade or so. Under IRHPA, the Institute for Plasma Research was set up. Under the thrust area programme scheme, many scientific research efforts have been supported. Satellite research programmes have generated new groups, summer schools and workshops have trained young people and participation in national and international conferences have been supported.
Today a qualitatively new scene has emerged, thanks to DST and the country is poised to take up major challenges in plasma science and technology. Major efforts such as the ones being contemplated need to have the support of a very broad-based national R & D programme. This will not only assist the development of the human resources but also generate the essential expertise in many key areas.
At this juncture, it appears that plasma community needs to be strengthened not only by the continued research support in the conventional areas but also by broadening its base by the promotion of the linkages between plasma science & technology and other fields of science and engineering. In the coming decade, DST can thus take up the challenging task of establishing these linkages. This should be easy because plasma science is particularly well suited for promotion of cross-disciplinary research because it directly impacts on many different fields of science and engineering.
To accelerate the pace of growth, while consolidating the present gains, an imaginative programme is critical for the future. However, the following critique of the present also needs to be taken into account in planning for the future.
A silver lining, which has a bearing on the proposals for the future is that cross-disciplinary plasma sciences have grown faster than traditional plasma physics. The traditional plasma science, however, continues to be of great relevance and importance and, though a major thrust in cross-disciplinary areas in being proposed, it is envisaged that the research and development activity in the conventional areas of plasma science, outlined below, will be strengthened by continued support from DST.
Conventional Areas of Plasma Science
Theoretical and experimental research, computer simulations, development of methodologies, tools, diagnostics etc. in the following broad areas of conventional plasma physics should be supported.
Cross Disciplinary Plasma Science
Common areas of interest between plasma physics and other physics disciplines exist and joint research activities in these areas should be supported and encouraged. A major mechanism for such activities could be through interdisciplinary workshops, seminars, summer/winter schools, conferences and support of research. The physics disciplines in which joint activities could be carried out are identified below. Major research community exists in each of these fields within the country.
The potential of the plasma to become excellent tool in material processing derives from some of the exotic properties of the plasma state. Plasma processing has taken roots in the country and is likely to grow because of the strong linkages it has established between disciplines, institutions and industries. It also symbolises the inherent strength of interdisciplinary programmes and their potential to thrive in this country.
Taking into account the strong enabling role of plasmas in physical phenomena of interest to a variety of disciplines, both basic and application-oriented, it is proposed that a major initiative be taken by DST in establishing a cross-disciplinary programme. The programme will have two facets; one in disciplines where plasma properties can be exploited as a tool and the second where the core technologies relevant to plasma sciences need to be developed.
The proposed programme aims at developing interfaces with a large number of disciplines in science and engineering. The success of the proposed programme depends critically on the excitement and interest that can be created among the scientific community from those disciplines. The following strategy is proposed :
HIGH ENERGY PHYSICS
High Energy Physics in universally recognised as a challenging and frontline area of Physical Sciences. Its basic aim is to uncover the fundamental constituents of nature and the laws governing their interactions. There has been remarkable progress in HEP in the last twenty years and one has been able to uncover one whole new layer of matter in this period. This is quite unprecedented in the history of mankind. As per the current understanding, the basic constituents of matter are six leptons and six quarks. There are four basic interactions among these particles out of which gravitational interaction is too weak to have any perceptible effect in the foreseeable future. The other three are all gauge interactions mediated by few gauge bosons. Whereas the strong interaction is described by the gauge group SU(3), the unified description of the weak and electromagnetic interaction is given in terms of the gauge group SU(2) x U(1) and the model describing these three interactions is popularly known as the "Standard Model".
For the last 10-15 years, this model is continuously being tested and till today its predictions are in remarkable agreement with almost all experiments. At the time of the last thrust area meeting in 1989, there were two major missing pieces in the standard model namely the top quark and the Higgs boson. However, the top quark has now been discovered at Fermilab Tevatron.
The last missing piece in the standard model is the Higgs boson. However, so far one does not understand the nature of the electroweak symmetry breaking in the standard model and as a result there is no firm prediction in the standard model about the Higgs particle mass. Understanding the nature of this symmetry breaking remains one of the most fundamental issues in HEP. One of the major aims of the Large Hadron Collider (LHC) which is being built at CERN, Geneva, Switzerland is to look for Higgs bosons up to a mass range of about 1 TeV. This is going to be one of the major activities in experimental HEP in coming 10-15 years.
While Higgs discovery will fit in the last missing piece of the standard model jigsaw puzzle, it is becoming fairly clear that the standard model cannot be the ultimate theory. There are several basic issues which cannot even be asked within the standard model. One of the major HEP activities in last 15 years or so has been to build models beyond the standard model which can answer some of these questions. Here, it must be made clear that so far no realistic model exists which can successfully answer all the questions. Among all these attempts, the ideas of supersymmetry and grand unification are worth mentioning. These models predict several new exotic particles none of which have been detected as yet and one of the aims of the LHC is also to search for some of these particles.
Thus, today HEP is at an interesting crossroad and one does not know which direction to follow. Not surprisingly, people are trying to explore several new directions. Some of these are, rigorous examination of the standard model, CP-violation, neutrino masses and oscillation etc.
On the formal side, it is widely felt that the ultimate unification of fundamental forces must also include gravity. One significant attempt in this direction is string Theory. There is no doubt that string theory represents the only known (perturbatively) consistent quantum theory of gravity. Recent developments about duality symmetry in string theory have added some fresh vigor to the theory. One of the remarkable offshoots of these developments has been a nonperturbative proof of colour confinement and chiral symmetry breaking in 4-dimensional supersymmetric Yang-Mills theory.
One of the major strengths of HEP is its wide interface with several other areas of Science. Special mention may be made of the areas of Condensed Matter Physics, Astrophysics, Nuclear Physics, Quantum Mechanics, Accelerator Physics and even Mathematics. This interaction has been mutually beneficial. Particular mention may be made of the area of "astro-particle physics" which has specially emerged in the last 5-10 years. Another such area is that of relativistic heavy ion collisions where both nuclear and particle physicists are interested in searching for a new phase of matter called quark-gluon plasma (QGP) which is one of the firm predictions of the standard model. So far no experimental signals have been seen and hence experiments are being planned at the upcoming machines at RHIC, Brookhaven, U.S.A. and LHC, Switzerland.
One of the key aspects of the modern high energy experiments is the use of major facilities in large laboratories, and working in large collaborating teams. The major existing accelerator facilities at the moment or which are expected to be available by the year 2001 are :
2. Stanford Linear Collider (SLC) with e+ and longitudinally polarized e- at 50 GeV + 50 GeV.
3. HERA at DESY, Hamburg, Germany where e- with 30 GeV collides on Proton of energy 800 GeV.
4. Tevatron p-p collider at Fermilab., U.S.A. with energy of 900 GeV + 900 GeV. It is undergoing major upgradation.
5. RHIC facilities at Brookhaven with 100 GeV / A+100 GeV / A.
6. Asymmetric B- factory at KEK, Japan where e- of 8 GeV collides on e+ of 3.5 GeV.
7. Asymmetric B-factory at SLAC, Stanford, U.S.A.
In the next phase, the LHC facility at CERN is expected to be ready by the year 2004 where p-p collision will take place at energy 7 TeV + 7 TeV. Heavy ion beams with 3 TeV / A + 3 TeV / A are also being planned.
Apart from the accelerator –based experiments, there are many important non-accelerator experiments in HEP which are trying to look for baryon decay, neutrino mass and oscillation, solar and atmospheric neutrino problem, dark matter detection etc.
Finally, extensive research work is going on in accelerator physics, specially about finding new methods of acceleration of particles. Vigorous attempts are being made to construct high energy linear e+ - e- collider with energies of 250 GeV + 250 GeV.
In last five years, Indian high energy experimental groups have been actively participating in the HEP experiments at various accelerators around the world and have made a mark in these collaborations. Some of these major collaborations are :
As far as commitments beyond 2001 are concerned, several Indian groups have decided to collaborate at LHC.
On theoretical front, the Indian groups have made substantial contributions in the areas of phenomenology as well as formal aspects including string theory. Special mention could be made of the contributions in the areas of non-critical strings, black hole physics in string theory, high energy string scattering, strong-weak coupling duality symmetry and Chern-Simons theory. Similarly, in phenomenology the Indian groups have made a mark in the areas of neutrino physics, tests of standard model, signatures of top quark, Higgs boson and superparticles, QCD structure functions and physics beyond the standard model.
Similarly substantial contribution has been made by Indian physicists in the interface areas between particle and nuclear physics, particle and condensed matter physics, particle physics and mathematics and astro-particle physics.
Based on the write-ups of various groups in the country as well as the deliberations during a brain-storming meeting, the following thrust areas are recommended to DST.
Apart from identifying the thrust areas, the following specific recommendations are also being made.
Adequate funding must be provided to the experimental high energy physics community to participate in experiments at the major worldwide facilities like CMS and ALICE collaborations at LHC, Switzerland, DO collaboration at Fermilab, U.S.A., PHENIX and STAR collaborations at RHIC, U.S.A. and BELLE collaboration at KEK, Japan.
A 10 GeV proton synchrotron be built in this country. It is understood that the Nuclear Physics community has also recommended the building of a similar machine in the country. It is therefore recommended that a joint committee of Nuclear and High Energy Physicists be formed immediately with a mandate to submit a feasibility report about such a machine at the earliest. Further, urgent steps be taken so as to ensure that adequate funding for such a machine can be provided during the IXth plan.
A meeting of experts in this field be called soon to suggest concrete plan of action involving both research institutions and the universities. The committee be asked to look into the possibility of building a facility in India as well as participating in top class international collaborations.
Research on exploring new methods of acceleration of particles should be vigorously pursued in the country. As a first step, we recommend that a small meeting of experts in this field be organized to suggest ways of actively promoting research in this field.
There is a strong need of a detector development laboratory. Institutions like the Nuclear Science Centre be approached with a request that they set up such a facility to be used by various groups in India.
The subject of nuclear physics has been around for a long time, but recently two developments have revitalised it. They are : (i) the availability of modern accelerators, which can provide beams of a variety of projectiles over a wide energy range, and (ii) the discovery that all strongly interacting particles (like, neutrons, protons, mesons, etc.) have structure and QCD is a theory of strong interaction. The hadrons (a generic name for all strongly interacting particles) are now known to be composed of quarks and gluons. Both these developments have affected nuclear physics in a big way. They have diversified its scope, highlighting thereby its multifaceted character, opened new vistas and have introduced an altogether new perception. For example, we can now have access to nuclear species which lie far from the beta stability line and could exist in states having exotic structures and extreme deformations. This enables us to undertake a programme of examining the behaviour of such systems, and that of other nuclei, under extreme conditions of rotation, density, temperature and deformation. Going beyond, we can now produce nuclear systems which consist not only of neutrons and protons, but have, in addition, a mixture of mesons, baryon resonances, hyperons and other hadronic states under a variety of conditions. This takes us into a completely new domain. It provides an opportunity to study the hadronic systems in compositions, which are completely different from that of the traditional nucleus sitting at the centre of the atom. Next, we have a distinct possibility of producing right conditions in the laboratory to initiate a phase transition from the hadronic system to a quark-gluon plasma. This and the fact that nuclear physics is dominantly the physics of strong interaction, provide in them the richness to elucidate the nature of strong interaction at its fundamental level and QCD in the non-perturbative domain.
Examination of the current national and international status of the research in above fields shows that nuclear physics right now is at a critical point. We have enough new data to show the appearance of new avenues, but not enough to reach definite conclusions. For example, there are enough indications to show the appearance of exotic structures like, superdeformations, linear chains, nucleon halos, limits on neutron and proton excess, etc., at selective places, but any general identification of their region of appearances and their understanding at fundamental level of nuclear structure is completely lacking. Similarly, while there are efforts to describe the isolated hadrons in terms of quark models, the procedure to describe the inter-nucleon interaction in terms of QCD is very much in its infancy. There are enough experiments to show the production of hadronic resonances (with strange, non-strange and charm quarks) in the nuclear medium and a systematic study of their properties and dynamics in nuclear environment is an important subject to pursue.
In addition, knowledge of nuclear physics is also applied to astro-physical and cosmological conditions. For example, reaction cross sections obtained from nuclear reactions (including reactions induced by radioactive ion beams) are of crucial importance in the calculations of stellar evolution. Similarly, nuclear equation of state is used in supernova calculations, neutron star calculations etc. The quark structure of hadrons becomes relevant when one considers transition from a neutron star to a quark star. Although this subject is inter-disciplinary, nuclear physicists have interest in and are in a position to contribute to this area.
It is, therefore, the most opportune time for us to organize our efforts in this country to ensure internationally competitive original contribution to this new phase of nuclear physics. It is imperative that we identify the topics and decide upon the strategies to promote them in the country. We should identify the future experimental facilities (short as well as long term) to perform appropriate experiments, and use the existing modern accelerators, here as well as abroad, successfully to extract answers to basic questions in a meaningful way. It is a challenging task. It requires efforts in the right direction and in a well-organized and sustained manner.
A broad categorization of the currently emerging areas which require special attention is :
Facilities and International Collaborations
In India, to our indigenously constructed VEC accelerator at Calcutta, we have added two pelletron accelerators, one at Mumbai and another at Delhi. And to augment these facilities further, projects are now underway to develop the superconducting linac boosters at the pelletrons and to install a completely new facility, the superconducting cyclotron, at Calcutta. Together, these accelerators would provide heavy-ion beams upto about 40 MeV per nucleon. This would satisfy the beam requirements for research under the headings 1-4 in the above list. However, an effective utilization of these beams require state-of-the-art experimental facilities at these accelerator laboratories and at the associated Inter-University Consortium at Calcutta. It is necessary to have a general purpose "Magnetic-spectrograph", a "Gamma-ray detector array (GDA) Facility", a "4p g - multiplicity array" and an "isotope separator" at these Centres. Specific proposals should be prepared for a general purpose "Magnetic-spectrograph", a "Gamma-ray detector array (GDA) Facility", a "4p g - multiplicity array" and an "isotope separator" to be installed at national accelerator facilities.
For research under other headings, we do not have any accelerator facility in our country. However, considering that the future growth of nuclear physics research and the associated accelerator technology development, on long term basis, would be intimately tied-up with these fields, our strategy here should have a judicious mix to serve us now as well as in distant future. In this context, such fields like investigations of quark-gluon plasma and relativistic heavy-ion collisions, which require enormous investments and high technology inputs, will be best served by international collaborative ventures at accelerator centres like CERN and RHIC. Collaborative proposals to carry-out experiments in high energy heavy-ion collisions and intermediate energy nuclear physics at internationally advanced accelerator centres should be promoted.
For research in intermediate energy physics and with radioactive ion-beams, it will be better to have a mixed policy. For the immediate purpose, we should promote collaborative work at international accelerators like COSY and SATURNE in Europe, IUCF and CEBAF in U.S.A. and RIKEN, RCNP and KEK in Japan. However, to keep up a culture in nuclear research and sustain creativity in different fields over a long time scale in the country, there should be significant research activity within the country. For this purpose, it would be appropriate to set up an accelerator facility in the country which can deliver radioactive-ion beam and multi-GeV hadron and heavy-ion beams. It is felt that such a facility can be set-up with reasonable investments and with the expertise available in the country. A national committee should be constituted soon to prepare proposals for this purpose. These proposals should include detailed physics utilization and the technical feasibility in the country of the identified machines.
To promote on-campus activity in nuclear physics in universities, one could contemplate setting up small "regional centres" in nuclear physics conterplate in different parts of the country.
ASTRONOMY & ASTROPHYSICS
While there continues to be significant progress in almost all the areas of astronomy and astrophysics, certain areas have seen very rapid progress because of the availability of (a) new large telescopes and detectors etc., and (b) vastly increased computing power available and the related new data processing tools; some of these areas are mentioned below.
The development of the techniques of helioseismology and stellar-seismology have now provided a new tool to study the interiors of the Sun and other starts, and provide a possibility of resolving the solar neutrino puzzle. In the recent past, modern large (upto 10m in diameter) optical and infrared telescopes and the Hubble Space Telescope have led to a dramatic (~ten fold) increase in the angular resolution (from 1 sec of arc to 0.1 sec of arc) and in the sensitivity. The availability of these telescopes with sharper images, and the development of large area imaging detectors in the visible and the infrared bands have led to a much more accurate picture of our own galaxy and the extragalactic Universe; radio astronomy had been so far preeminent in the observations at large redshifts (z > 1), but now the optical and near infrared telescopes are also probing these deep reaches of the Universe. Advances in space based observatories for far infrared EUV, X-ray and g -ray bands have opened up a whole field of high energy astrophysics. Gravitational lensing is being used very effectively to investigate the distribution of matter (particularly non-luminous) in our galaxy as well as in the far reaches of the Universe – it is interesting to note that former is realised by special data collection techniques on small telescopes, while the latter is possible due to the increased sharpness of the images provided by the Hubble Space Telescope and some modern ground-based telescopes. A new European Infrared Space Observatory has been launched in November 1995 and is expected to vastly improve our understanding in the areas of planetary systems, protostars and young massive stars, ultra luminous galaxies, interacting galaxies and large-scale structure of galaxies.
Significant advances have been made in the understanding of radio-galaxies, quasars and other active galaxies, using multiband (from radio to g -rays) observations; the importance of multiband observations can be exemplified by the IRAS survey in the far infrared band which identified many galaxies with extremely high luminosities in excess of 1012 solar luminosity. These different types of active galaxies pose a number of challenging astrophysical problems related to the triggering of such highly energetic activity in a small fraction of galaxies, the evolution of such activity with cosmic epoch, the physical processes responsible for the generation of such large amounts of energy, the role of the environment, and the transport of energy to the outer lobes of extended radio sources over distances of hundreds of kiloparsecs. Continuing advances in high-resolution radio and optical observations of many of these objects provide us opportunities to study the interaction of the jets with the interstellar media of the host galaxies as the jets propagate outwards.
Pulsars, discovered in 1967 by Cambridge astronomers, are rotating neutron stars and their radio emission mechanisms are still not well understood. The discovery of binary and millisecond pulsars in the seventies gave a new fillip to the study of pulsars. Binary pulsars are considered to be recycled pulsars; i.e. very old pulsars resurrected and spun up to an equilibrium period determined by their magnetic field. Binary pulsars are also being looked at as candidates for earth like planetary systems and have already been used successfully for verification of the general theory of relativity. Further, the bursts of gravitational waves, expected during coalescence of the components of binary pulsars, provide exciting prospects of a direct detection of gravitational waves in the foreseeable future; rapid strides have been made recently in the techniques of detecting these murmurs of faraway catastrophies.
The milli-arcsecond accuracy astrometric data being provided by the HIPPARCUS satellite has provided the possibility of a precise linkage of the radio astronomy frame to the optical frame of reference, and of studying dynamics of our galaxy in more details.
The recent detection of the fluctuations in the cosmic thermal background radiation (~3K) has added a new dimension to the study of large scale structure of the universe and its history. These observations allow cosmologists to integrate forward the equations of motion governing gravitational instability with realistic initial conditions, and to check theoretical models of structure formation against the observations. The increasing depth and sky coverage of the redshift surveys, together with the large N-body simultations and semi-analytical methods studying gravitational clustering, promises to yield very exciting results as the dialogue between the theory and observations intensifies in the near future. The various cosmological studies are now narrowing uncertainty in the age of the universe in big-bang models, and simultaneously stellar studies are giving improved limits on the age of our galaxy to constrain the big-bang models.
Theoretical and experimental work is being done in the country in many of the areas mentioned above. While the computational facilities for numerical-theory are quite good at least in several centres, the same cannot be said of the observational facilities in general. Among the major observational facilities in the country, one could list: the Ooty Radio Telescope (TIFR), the MM Wave Telescope (RRI), the Low Radio Frequency Arrays (RRI-IIA), the IPS Array (PRL), one meter class optical telescopes at Nainital (UPSO), Rangapur (OU) and Kavalur (IIA), the 2.3m VBT at Kavalur (IIA), and the recently commissioned 1.2m optical-infrared telescope at Mt. Abu (PRL); the solar telescopes at Kodaikanal (IIA), Udaipur (USO), Nainital (UPSO).
Far-infrared, X-ray and g -ray astronomical observations are carried out using the balloon facility of TIFR at Hyderabad. A X-ray camera will be launched on the Indian PSLV. BARC and TIFR have set up telescopes at Mt. Abu, Pachmarhi and Ooty for high and very high energy g -ray observations. Udaipur Solar Observatory is one of the six observation stations for the GONG project on solar-seismology and this would provide Indian astronomers an excellent opportunity to exploit this exciting field.
Soon the Giant Metrewave Radio Telescope (GMRT) of NCRA-TIFR is expected to be operational at a site 80 kms north of Pune – this telescope would observe in six bands distributed between 50 MHz to 1420 MHz, with an array of 30 parabolic dishes, each of 45m diameter distributed over 25 km, with unprecedented sensitivity ranging between about 5 mJy at 50 MHz and 0.1 mJy at 1420 MHz. These observations would make outstanding contributions to the understanding of extragalactic, galactic and solar-system objects. In the next few years, IIA is planning to install a 2 m size optical-infrared telescope and IUCAA is planning to install a 1.5 m optical telescope as a facility within the University sector.
Thus, in the last 5 years, the only addition to the optical infrared telescopes has been a 1.2m telescope, in contrast to the international scene exemplified by the 10m Keck telescope, and the expected commissioning of several 8m class telescopes in the near future. Whereas, GMRT would provide an outstanding new facility for observations in the radio band, the situation is not so promising for the optical and other bands of observation. While a restricted access is available to Indian astronomers on some of the (foreign) large telescopes etc., either through long-term collaborations or through individual proposals for observations, there is a strong need to for augmenting our own optical/infrared facilities. In particular, there is a need to have a few more of 1-2m class optical-infrared telescopes, and a 4m class optical-infrared telescope with advanced instrumentation to follow up the observations made by GMRT (radio) and the smaller optical telescopes. Simultaneously, support is required to provide opportunities for making observations with large optical telescopes overseas and for using data from the various archives.
Manpower generation is a very serious challenge and requires urgent attention. The various national institutions have been providing unstructured support to the University sector in the past. The Inter University Centre for Astronomy and Astrophysics (IUCAA) has been promoting astronomy in a focused manner in the University sector as its mandate since its inception. But more input is required to upgrade the facilities in the University sector in order to generate the manpower for the future and special provisions must be made for it; IUCAA can provide a useful advisory role towards the upgradation.
Keeping in view that there is an urgent need to upgrade our observational base in many bands and to grow trained manpower for the future, the following recommendations are made :
During the past decade, efforts have been made to identify and characterise good sites for optical and infrared astronomy in the country. But there is need to support more work. A reliable characterisation needs use of modern detectors to measure seeing, cloud cover, water vapour column, optical and infrared backgrounds etc., and it is a time consuming activity. As the effectiveness of a large telescope depends critically on the quality of the site, ready availability of the data on potential sites will help to make the right decisions for installing the telescopes.
In case an excellent site cannot be found in the country for a 4m telescope, it could be placed on an excellent international site (e.g. Chile or Southern Africa) as a collaborative project with a foreign country.
Development of the detectors for space astronomies (far-infrared, X-ray and g -ray) should be supported with a view to creating the base necessary for taking up major observational programme in future.
Nonlinear Dynamics constitutes frontier fields of research of highly interdisciplinary nature. Integrability and chaos are two of the main concepts associated with nonlinear dynamical systems. They have revolutionized our understanding of dynamical phenomena at a very basic level, which occur in a vast variety of branches of physics, chemistry, biology, engineering, social sciences, economy and so on. These phenomena include the existence of highly coherent localized structures with their remarkable stability properties, bifurcations, instabilities, onset of chaos, change of ordering, phase formations, spatio temporal patterns and so on. Sophisticated mathematical tools such as inverse scattering transformation method, various bifurcation theories, group theoretic and geometric methods of analysing dynamical systems and so on have been developed. These studies not only help to unravel novel phenomena in dynamical systems described by nonlinear ordinary, partial and difference-differential equations and maps, but also have enriched the underlying mathematical topics. Thus Nonlinear Dynamics has become a meeting ground of ideas from mathematicians, physicists, engineers, chemists, biologists and others.
In this connection highly stable exponentially localized structures called solitons are often associated with many of the integrable nonlinear systems while motions which are sensitively dependent on initial conditions are associated with chaotic systems. Besides dramatically raising our perception of many natural phenomena, these concepts are opening up new vistas of applications and unfolding technologies. Optical soliton based communication technology, magneto-electronics, nonlinear electronic circuits, controlling and synchronization of chaos and their applications in secure communications and cryptography are some of the potential technological applications within immediate reach. These developments have raised further interesting new questions. Extension of the notion of integrability and chaos to the quantum domain has helped to explore atomic, molecular and many body systems as well as statistical systems in a rigorous way unravelling various mysteries of the microworld. One might say that the field is growing to a stage where initial surprises about the various phenomena are waning but more intense analysis of them are being pursued to realize the fruits of these investigations.
Though work on Nonlinear Dynamics started rather late in India, may be in 1970s, during the past 25 years or so, the country has seen impressive results coming from various groups, mostly working in isolation, both at the fundamental and applied levels. DST has played a crucial role in this endeavour by identifying nonlinear Dynamics as a Thrust Area at an early stage. This has prompted many groups to pursue research in Nonlinear Dynamics in an intense way. The general areas of contributions consist of both the topics of integrability and chaos and they may be summarized as follows.
The contributions in the area of integrable systems include the development and applications of various methods of identification of integrable systems using singularity structure analysis, Lie and Lie-Backlund symmetry analysis, Lie algebraic, group theoretical and differential geometric methods, reduction of Yang-Baxter equations at classical and quantum levels and so on for discrete and continuous nonlinear systems described by nonlinear difference, differential and partial differential equations describing a wide variety of physical phenomena ranging from fluid dynamics, plasma physics, condensed matter to particle and astrophysics. New algebraic structures and hidden symmetries inherent to quantum integrable systems have been discovered and new integrable systems generated using quantized as well as braided algebras. Investigations of the properties of integrable systems including solutions, Hamiltonian structures, conservation laws and integrals of motion and so on using inverse scattering method, Hirota Bilinearization method, d-bar method, differential geometric and group theoretic methods have revealed much understanding of the properties of integrable dynamical systems. Applications include vast variety of topics in fiber optic communications via optical solitons, fluid dynamics, various circumstances in plasma physics, condensed matter, nonlinear optics, liquid helium, ferromagnetic spin systems, field theory and particle physics, astrophysics and so on. Quantum integrable systems such as generalized Calogero Moses-Sutherland systems, various spin models, and soliton systems, their spectrum and states, the associated Yang-Baxter equations have also drawn considerable interest.
Investigations in the field of chaos so far can be categorized into various topics: the analysis and understanding of the fundamental aspects of bifurcations and chaos; identification of routes and mechanisms towards onset of chaos; characterization of chaotic attractors; applications to different classes of dynamical systems, spatio-temporal patterns; controlling and synchronization of chaos and their applications to secure communications. Variety of model systems including low-dimensional maps and oscillators encompassing all areas of physics and chemical oscillations as well as special biological oscillations and wave propagation such as in neuronal systems have been considered and their properties elucidated. Complexity and onset of turbulence in models such as Fitz Hugh-Nagumo, Ginzburg-Landau equations, coupled map lattices and oscillators were studied. Various statistical mechanical aspects of chaotic behaviour in maps and oscillators were also studied. New nonlinear electronic circuits were introduced.
Quantum behaviour of classically chaotic systems, namely quantum chaos, was also studied for its various aspects. Motion of eigenvalues and eigenfunctions as a function of nonintegrability parameter and the relation to integrable dynamical systems, applications of periodic orbit theory and random matrix theories in quantum chaos studies were also considered in detail. The ideas were applied to problems such as quantum nonlinear oscillators, kicked rotators, Rydberg atoms and molecules in various external fields.
The above topics are only of indicative nature and due to the extremely interdisciplinary nature of the field investigations on all related topics will be encouraged.
LASERS, OPTICS, ATOMIC & MOLECULAR PHYSICS
After taking stock of the existing expertise in the country, the ongoing work and the international scenario, the following sub-areas in the fields of lasers, optics and atomic & molecular physics should be supported.
The field of Nonlinear Optics and Spectroscopy is well recognized to be very important because of many existing devices based on these effects. There is an even larger variety of potential devices generally called photonic devices which will be commercialized in the coming decade. Besides, nonlinear optical effects have played a crucial role in enhancing our understanding of the quantum nature of light. With deeper understanding of the nonclassical states of light generated in nonlinear devices, it can be safely predicted that a new range of sophistication in optical devices will come. Nonlinear spectroscopy plays an important role in diagnostics and basic research in atomic, molecular and condensed matter physics.
DST has already sponsored several major programmes in this field and substantial progress has been made in several areas. Surface SHG has been used at IACS to study molecules dispersed on a liquid surface. Vibrationally cold and rotationally flexible molecules such as acetone have been investigated at IACS and BHU. Also investigated at BHU are "dark excited" states of molecules by photo acoustic spectroscopy and multiphoton ionization spectroscopy. Optogalvanic spectra of Ne, Ar and I2 were also investigated at BHU. Nonlinear optical interactions in dye doped Boric acid glass were studied at IITK and a polarization logic scheme based on this was demonstrated. Raman spectroscopy was exploited to study phase transitions. Laser produced carbon plasmas were studied to find possible route to formation of fullerenes. Various other nonlinear optical activities in the country include optical frequency conversion studies at Burdwan University; investigation of third order nonlinearities in semiconductor doped glass and metal particles at CAT. The methods used so far are Z-scan and intensity dependent absorption in picosecond and nanosecond range. Mechanisms of optical limiting in fullerene solutions have been identified by detailed experiment and analysis. Pump-probe methods have been used at TIFR to investigate the ultrafast (picosecond) dynamics of photo induced carriers in several important semiconductors. In Chemistry Division; BARC, a picosecond pump probe system has been used to do time resolved excited state spectroscopy of many chemical species. Work is in progress on organic nonlinear optical materials at IIT Mumbai, Hyderabad University and CAT.
The technical areas where we feel urgent initiatives are required are laser and other methods of cooling of atoms in traps, nanostructure fabrication facilities and experimental investigation of electromagnetically induced transparency and other coherent nonlinear optical phenomena. We believe that the most effective way to start experimental activity in the area of laser cooling and related atom optics is through a collaboration between some academic institutes and a national laboratory like CAT which has infrastructure for UHV and electronics.
The parametric oscillators have a great future as sources of tunable radiation over a very wide range. It is important that the country must get in a big way in such studies involving crystals like BBO, lithium triborate.
We strongly feel that would be very desirable to have a series of 4 or 5 annual SERC schools on Nonlinear optics and spectroscopy. It is suggested that a small organizing committee should organize them sequentially as is done in condensed matter physics. It is also important that the courses have 10 to 15 lectures per course and in some crucial areas like atom optics a few experimental experts should be invited from outside India. It would be a very effective way to lure youngsters.
B. Quantum Optics and Basic Laser Physics
The trend of research in quantum optics indicates that the following areas will be active research areas for the next several years:
Optical Vortices Production and propagation – interactions of vortices in free space and nonlinear media – interferometric studies – effect of polarization – vortices in quantized light.
Optical Manipulation of Atoms Using Coherence Laser fields to control the quantum mechanical state of the constituent atoms of a medium and hence the absorptive, dispersive and nonlinear properties of the medium – enhancement in the efficiency of nonlinear processes – local field correlations in nonlinear noise quenching (in correlated emission laser, squeezed laser and laser without population inversion etc.) – pulse propagation without absorption or dispersion production of statistics matched fields.
New Laser Systems and Lasers Without Inversion (LWI) Light amplification by coherence – quantum theory of cw-modeless lasers-Input-output coupled cavity lasers: quantum theory, instabilities etc., and theory of excess noise – Nonlinear and quantum theory of lasers without inversion – spectral energy condensation in LWI – Instabilities and spatio-temporal structures.
Cavity QED and Photon Localization Quantum Monte-Carlo studies of nonlinearities in cavities – Micro structures for the study of strong interaction between radiation and matter-Spontaneous emission and other radiative effect in periodic layered structures – Dipole-dipole interaction in microcavities – Cavity QED and quantized motion in traps – Quantum statistical properties of single atom laser.
Quantum Optoelectronics Semiconductor heterostructures and quantum optical properties of radiations from these micro and nano systems – large nonlinear optical effects in multiple quantum wells (MQW’s) due to quantum confinement of the carriers – their functions as all-optical switches and logic gates -–QED of such structures – new regimes of cavity nonlinear optics.
Traps and Laser Cooling Effects of trap potential – cooperative and correlation effects – Atom optics – atomic interferometry and applications in high precision microscopy and lithography – Effects of quantum statistics; bosonic versus fermionic.
Nonclassical Light and Fundamental Lasers Nongaussian nonclassical light – Coherent and squeezed states for SU (3) and other Lie groups – Diphoton coherent states – production of Schrodinger cat and kitten states – criteria for nonclassicality – correlations induced optical effects – nonlinear optics in the quantum regime: squeezed pump on BBO states of K_-new schemes for production of nonclassical light – nonlocality without Bell’s inequalities – nonlinear optics of Bose Einstein condensate; interferometry at single photon level.
Borderline Areas Research in the borderline of other areas like condensed matter physics and quantum field theory will be expected to be pursued with greater vigour in the forthcoming years.
C. Modern Classical Optics
In recent times the classical optics has undergone a big change. Not only basic new ideas are emerging, but it is resulting in very large number of device and engineering applications some of which are listed below:
Geometric and Group Theoretic Methods As techniques for concise formulation, simplification, analysis and classification in classical and quantum optics-symplectic structures-invariants of various orders and types –generalized coherent states-abelian and nonabelian geometric phases.
Beam Propagations Partially coherent beams – correlation-induced spectral changes in propagation and passage through optical systems-microscopic theory of their origin-Fractional Fourier Transform in optical processing-Talbot phenomenon-Wavelet transforms-diffractions in sub-wavelength structures and evanescent waves –near field optics-launching of evanescent waves in optical fibres.
Transverse Structure Spatial and polarization structure across a realistic finite beam-quantizations-aberrations for vertical beams-interplay between aberrations and polarization.
2-D Optics Design and production of 2-D optics, Design involves application of physical principles of optics-diffraction theory-and the production is through lithography and/or direct writing. Direct writing could give multiphase steps resulting diffraction efficiencies upto 100%. Custom tailored wavefronts can be obtained. Areas of applications will be testing of aspherical optics to actual optics in processors and scanners. The optics requires spectrally pure light and hence has applications only in instruments which employ laser as a source. Holography-particularly holographic optical elements are included and research needs to be directed to obtain holographic optical elements on photo polymers and organic materials.
In order to write the 2-D optics, laser beam writer is one of the many writers available. Its development will involve several technologies like producing sub-micron light spots, computer controlled x, y, z movements of the substrate as per the design data.
Optical Instrumentation Laser based instruments with full automation for measurement and process control should be developed. There are plenty of instruments exploiting laser characteristics and concerted effort in their development will be highly useful for making them economical.
Optical Processing A programme to utilize the existing knowledge in optical processing particularly directed towards signature identification and development of new algorithms and study of transforms like wavelet transform should be taken up. This area requires detailed studies in architecture and algorithms. Correlators for quality control and inspection are routinely used. Infact optical processors utilize SLMs and incoherent to coherent converters. Work on 2-D optics will find immediate applications in these processors as a replacement of bulk optics by 2-D optics will make them compact and light weight. Work in areas like Fractional Fourier Transform and other transforms should also be taken up. This requires both a strong theoretical and experimental group and hence Mat Sci. / IITM / IITD and IRDE Dehradun would make a very promising team with user and developer involved.
D. Optical Fibre Lasers and Amplifiers
Optical communication using fibre optics is one of the most useful technologies that has evolved in the past two decades. Enormous information capacity (10 terrabits) is available via fibre optic communication systems and in the developed world, telephones, cable T.V. and multimedia are worked via optical fibre systems. Fibre optic communications is coming up in a big way in India. Optical fibres are being manufactured by (1) Optel, (2) Hindustan Cables, (3) Siemens, (4) Goenkas Group of firms, (5) Birla Group of firms. The cables are being laid by DOT for telephonic communication links. The signals are currently generated with LEDs and every 20 km there is a repeater. This process is costly and requires frequent maintenance. Optical fibre laser sources and optical fibre amplifiers can and are replacing LEDs in current state-of-the are communication system in developed countries. The repeater distances get separated to 165 km. Noise is reduced compared to LEDs and with soliton based techniques repeater distance upto 10,000 km have been reported. The enormous channel capacity permits several hundreds of telephone lines to be used via a single cable.
The main technologies presently commercially unavailable in India are with respect to:
In India experimental R & D these aspects is being carried out at
(1) I.I.T., Madras Optical lasers/Optical amplifiers/Solitons/
(2) I.I.Sc., Bangalore Opticalswitches/Optical modulators.
(3) C.G.C.R.I. Materials for optical fibre amplifiers/
Rare Earth Doped Fibres.
At I.I.T. Delhi there is a large group working on theoretical aspects of optical fibre. Optel at Bhopal has at a meeting at I.I.T. Madras expressed an interest in the amplifiers developed at I.I.T. Madras and wishes to interact with them at the final stage of end product testing.
It is necessary as of now to have a coordinated effort to do basic research and device development in the fields of optical fibre amplifiers/optical fibre lasers/and related modulators/switches etc.
E. Atomic and Molecular Physics
The field of atomic and molecular physics is driven by experimental activity in the field and by other fields which crucially require inputs from atomic and molecular physics. This field has, in the last two decades, witnessed a surge of activity primarily because of certain technological advances on one hand, and because of the realization by researchers of the interrelation of this subject with various fields of physics at the basic level. On the technological front developments, namely those of laser technology and of computers have had a profound effect on both experimental and theoretical developments. Indeed it may be said that the emergence of new research domains in atomic and molecular physics depends crucially on the successful utilization of these technologies.
There are very few centres of experimental activity in modern atomic and molecular physics in India such as the ones at PRL, Ahmedabad, TIFR, Mumbai, IACS, Calcutta. Studies involving modern spectroscopic studies of atoms and molecules are largely being done at BARC, Mumbai, BHU, Varanasi, Cochin University. The major theoretical groups are at IACS, Calcutta, Roorkee University, IIT Chennai, IIT Kharagpur, PRL, Ahmedabad, Meerut University. Besides these centres, some research work done in the area of theoretical quantum chemistry and condensed matter physics is close to research work in atomic and molecular physics. Some of this research work, for example, on molecular dynamics is being done at IIT Kanpur, while work on the atomic structure of clusters is being done at University of Pune and IOP, Bhubaneshwar.
The challenging areas in atomic and molecular physics which can be profitably pursued, based on this review and on national and international status of research, are given in the following paragraphs:
Atomic Physics and Tests of Fundamental Theories
The experimental studies in this area mainly involve precision measurements on atoms involving ultrahigh resolution atomic spectroscopy. Advances in quantum electrodynamics, lamb shift of hydrogen, spectroscopy of muonium and positronium, electro-weak interaction manifestation in parity violation and many other aspects of fundamental problems are investigated through atomic physics. On the theoretical front detailed relativistic calculations of atomic structure are required to complement experimental work.
Atomic and Molecular Structure
The calculation of accurate data for atoms and molecules of interest in other fields requires specialised skills and is very demanding. The need for particular data must, however, be clearly indicated. Furthermore, as mentioned above, for heavy atoms, relativistic theories need to be employed, and much work needs to be done. Multiconfiguration relativistic studies of atoms and ions and studies of relative transition strengths in radiative and non-radiative processes for iso-electronic sequences are also important. The structure and physics of small clusters is an important area of research.
Atomic and Molecular Collisions
Studies of collisions of electrons/positrons with multi-electron atoms at low and intermediate impact energies provide information about many body effects and correlations. Some studies are currently being done in the country but more work needs to be done. Charged particle impact ionization of multielectron atoms and (e, 2e) collision processes provide challenging problems as also electron collisions with oriented molecules which are expected to reveal new spin polarization effects. Ultracold collisions between multielectron atoms and collisions involving Rydberg atoms need to be pursued.
Accelerator Based Atomic Physics
Some work on beam foil spectroscopy has been done at TIFR, Mumbai. The pelletron facilities at TIFR and NSC, New Delhi, both seem to be underutilized and it is desirable to develop experimental activity using these facilities. At VECC, Calcutta, an ECR Ion source has been developed and atomic physics of hollow atoms can be studied with such a source.
Photon Impact Studies of Atoms and Molecules
Laboratory measurements, in the UV and the VUV region of the spectrum, of photoabsorption, photodissociation and fluorescence cross sections of molecules of interest for studies of planetary and terrestrial atmospheric studies are urgently required. Some measurements are already being made in the country but much work still remains. Measurements using lasers are confined to weakly flourescing species, measurements of radiative life times of excited states and multiphoton ionization of molecules. Studies, both experimental and theoretical, of UV and of VUV fluorescence from atoms and molecules following inner-shell absorption of synchrotron radiation are becoming important as also the study of atomic and molecular states involving core-excited and core-ionized states. The study, both experimental as well as theoretical, of non-dipole effects on photoelectron angular distributions following ionization of atoms or molecules is of relevance to photoelectron spectroscopic studies of surfaces and materials.
Atoms and Molecules in Intense Fields
This field opens up new domains in quantum physics and is of fundamental importance. Research activity, both theoretical and experimental needs to be strongly supported. In particular two electron systems in strong fields and molecular dynamics in intense electromagnetic fields are of much current interest. Few electron atomic systems in strong external fields provide real physical examples of chaotic quantum systems and while some theoretical work is being done on chaotic quantum systems many important basic problems remain. Ultra intense fields are expected to give rise to relativistic electron production and multiphoton Compton effects.
F. Crystal Growth
Several laboratories in the country such as CAT, Indore, IISc Physics Department, Burdwan University and Anna University have the capabilities for crystal growth, characterization etc. However, now we should have a coordinated effort and should evolve a major national program in this field. There is an urgent need to concentrate on the production of a few selected commercial-grade crystals for laser related applications. These include laser host crystals like Nd: YAG, Ti : Al2O3 as well as NLO crystals, SBBO, KTA, AgGa2SP4, AgGaS2 and related crystals. The work involves crystal growth, characterization, and device feasibility studies.
G. Physics of Biological Systems
The major thrust of a modern biologist is to understand and explain biological function in molecular terms. The development of molecular biology in the last few decades has opened the prospects for understanding the function, reactivity and properties of biological systems in terms of molecular structure. Biological systems are complicated both chemically and physically and undergo reactions and interactions continuously.
With the basic structural information available from X-ray techniques, there arises a need for spectroscopic and other techniques to monitor structural features and dynamical changes which accompany biological function in solution. The molecular vibrational frequencies are sensitive to geometric and bonding arrangements of localized group of atoms in molecules and reflect intermolecular interactions as well. With the availability of tunable and ultrafast lasers from UV to near infrared and improved multichannel detection techniques, it is possible to match the frequency of the exciting radiation with the electronic absorption of a particular segment of a complicated biological molecule so that vibrations from only the absorbing chromophor are resonance enhanced. A very sensitive and selective resonance Raman (RR) technique probes structure-function, structure-property relationships, electron transfer processes in photophysical processes in hemeproteins and visual pigments and associated structural changes etc. Both steady state and time resolved studies are being performed.
Availability of intense, tunable, ultrashort laser pulses in the recent past has opened prospects for studying ultrafast dynamical processes occurring in the ps or even fs time domain. Various phenomena like chemical reaction dynamics and probing of short-lived transient species, photo-induced electron transfer, charge separation and recombination, and other photophysical processes, protein dynamics, photodissociation of axial ligands and subsequent relaxation of heme-protein and model systems, excited state isomerization reactions etc. are now possible to probe in the time domain which afford new opportunities and challenges for detailed understanding of various processes. Time-resolved absorption and luminescence techniques provide information on life times and absorption of transient species generated during laser irradiation while time-resolved Raman and RR techniques provide structural information and other details of the transient species generated during photophysical processes. Several academic institutions like NEHU Shilong, Kumaun University, Nainital, BHU, CAT are already deeply involved.
Some of the challenging areas were research should be strengthened / undertaken are:
It is important that several national projects are evolved so that different groups from different institutions can collaborate. Some of these national projects should be in the following areas :
These national projects will be in addition to providing major funding to select groups at different institutions.
Centres of Excellence
The Department of Science & Technology must create Centres of Excellence around persons with proven track record. There are several possibilities:
Such Centres of Excellence must ensure that the number of workers from neighbouring institutions are also involved in one way or the other, so that the scientific community in the region where the Centre is located benefits.
Organisation of Schools
As emphasized in the "General Recommendations" below, there is continuing need to organize school for manpower training in far greater numbers in many areas. It is suggested that the following schools be conducted in the next few years.
It will also be worthwhile to have a school on Computational Methods in Physics and Chemistry. Such a school can be jointly organised by different PACs.
It is very often noticed that some of the major equipment stops functioning and thus quite a lot of equipment go unutilised. Even sometimes there is no money for the maintenance of the equipment after the project is over. We have to develop some mechanism so that funds are available for maintenance of the equipment.
Finally, it is highly desirable to have joint programmes between teaching institutions and national laboratories, so that one can use the technical infrastructure of national laboratories. DST could foster such a relationship by instituting some kind of a programme, say on the pattern of ICTP where scientists have an opportunity to go and work at national laboratories for 2-3 months in a year.
Some Common Promotional Needs Of All Areas In Physical Sciences
Continued supply of trained quality manpower remains the single greatest worry of all the communities. It is not surprising that, in all areas, very similar recommendations have been made to remedy the situation which are summarized below:
(a) Physics Graduate Training Programme: In most universities, there is no programme equivalent to the predoctoral course which is running in most research institutes. It has been recommended that a graduate level training programme be initiated. This could be organized on a regional basis with the help of research institutes in that region which are already running a similar programme.
(b) Summer Training Programme: Bright and motivated students who have just passed their B.Sc or M.Sc first year should be given summer training for about two months. There are several university departments and institutes which are willing to run this programme and their help could be sought in running it.
(c) SERC Schools: The well-known SERC Schools have been judged to be of utmost importance and value at the pre-Ph.D stage and organization of these Schools in all areas has been recommended.
In High Energy Physics, there is a recommendation to hold separate Schools on Theoretical and Experimental aspects. They also feel that some Advanced Schools be held on theoretical aspects with international participation covering topics at the cutting edge of research and pitched at a higher level than SERC Schools.
In Plasma Physics, it has been recommended to continue the SERC Schools with themes oriented towards support of cross-disciplinary activities and various national programmes.
(d) Workshops, Conferences, Symposia, etc.: To facilitate interaction among practising scientists, it is felt that organization of national and international workshops, conferences, symposia be facilitated, Similarly, facilitating participation by Indian scientists in international conferences is also important and necessary.
The High Energy Physics community has strongly felt that the very successful series of Workshops on High Energy Physics Phenomenology (WHEPPs) be funded on a regular basis. These should be supplemented by Workshops on Experimental High Energy Physics.
Among the newer concepts are "Mini Workshops", advanced by the High Energy Physics community which will enable the national workers in a specific area to meet for a week and jointly work towards joint investigations.
The Nuclear Physics community has desired that a Nuclear Physics Seminar Circuit, along the lines of the Theoretical Physics Seminar Circuit (TPSC), be started which should have participation by experimentalists as well.
In several areas, quality and ‘competitiveness’ of research crucially depends on the availability of state-of-the-art computing facilities. It has been recommended that attempt should be made to have a networked supercomputing facility which can be accessed by any institution in India.
The Plasma community has felt that computer simulation of plasmas should be promoted.
Use of e-mail, bulletin boards, internet, etc. have become indispensable in modern day research. Setting up of these facilities, especially in university departments, should be speeded up. Such facilities will also provide scientific literature at a moderate cost and will effectively complement library facilities.
The Plasma community has suggested that a documentation centre to cater to the needs of the community should be established to enable scientists in various colleges and universities to have access to research documentation. Similar services by one of the Astronomy centres has also been thought of by the astronomy community.