Missed opportunities
There were many opportunities for the advance of fundamental research in our country. This essay describes how we missed them. It has been written with the hope that we will advance by using these opportunities at least from now onwards.
Sathyandra Nath Bose
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In the year 1924, S N Bose discovered the statistics of photons.
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Already in 1900, Max Planck had initiated the quantum revolution through his research on black body radiation. But what he did was not straightforward.
The only rational derivation of what is now called Planck distribution is to follow the method of Maxwell and Boltzmann who derived the velocity or energy distribution of molecules.
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But Bose found that this calculation will yield the correct Planck distribution formula for the energy distribution of photons only if he assumes that boson are identical particles.
This concept of identical particles is characteristic of quantum mechanics. There is no place for this in classical physics. Two cricket balls may look the same. If we throw them, they will follow different trajectories and hence we can see their difference. In quantum mechanics, two electrons will not go in different trajectories.
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They move as waves; their difference cannot be recognized. Therefore the concept of identical particle is applicable in quantum mechanics.
S N Bose used the identical-particle nature of photons and deduced the Planck formula.
After that, Einstein discovered that some other molecules also can behave like identical particles and extended Bose's discovery. This is called Bose-Einstein statistics.
Particles with spin such as electrons follow Fermi-Dirac statistics. Photon has spin and it follows Bose-Einstein statistics.
Particles with spin follow Fermi-Dirac statistics while particles with spin follow Bose-Einstein statistics.
From S N Bose's discovery in 1924, it is possible to create the whole quantum mechanics. For, his idea of identical particles is possible only in quantum mechanics. As already explained, this is because of particles behaving as waves in quantum mechanics. Hence, further study of Bose's concept of identical particles will lead to quantum mechanics. In India this could have been done either by Bose's colleagues or his students.
But, within a few months of Bose's discovery, Werner Heisenberg and Erwin Schrödinger created quantum mechanics. This was a missed opportunity for Indian science.
The Bangalore incident
In the summer of 1961, the summer school of Tata Institute of Fundamental research was held at the Indian Institute of Science, Bangalore. Richard Dalitz and murray Gell-mann were the lecturers. The audience was students like me and senior scientists like Homi Bhabha, MGK Menon, SN Biswas, LK Pandit, Virendra Gupta, Yash Pal and Alladi Ramakrishnan.
Gell-Mann lectured about his "Eightfold Way". This was based on Sakata's
SU(3) symmetry, but different in an important way. Gell-Mann lectured on this at Bangalore even before it was published.
In Sakata's SU(3), proton, neutron and lambda were the triplet. In Gell-Mann's eightfold way, these three particles were part of an octet.
At the end of a lecture, Dalitz asked a question: " Why did you leave out the triplet? Without the triplet, there is no meaning to SU(3)!" Gell-Mann evaded this question. In spite of Dalitz's repeated questioning, there was no reply from Gell-Mann.
If Gell-Mann had replied, "quarks" would have been born in 1961 at Bangalore, without waiting until 1964, when Gell-Mann and Georg Zweig independently proposed quarks. If any of us had replied, it would have been a major Indian discovery. This was a missed opportunity.
Gauge Theory
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In the year 1959 I read J J Sakurai's very interesting paper in Annals of Physics. It is Sakurai who was the first to use Yang-Mill's theory in particle physics. He used it to construct a theory of strong interactions.
From that time I was very much interested in Yang-Mills theory and believed that it will become the basis of particle physics.
In 1964, in the Varenna summer school,Martinus Veltman talked about the conservation of weak currents and I realized that weak interactions must be based on Yang-Mills theory.
Therefore, when Weinberg's paper on came out in 1967, I did not have any doubt that it was the correct theory for weak interactions. I learnt the full details about spontaneous symmetry breaking from the papers of Goldstone, Higgs and Kibble.
In the next two or three months, I lectured on these things at TIFR and other institutions. In particular, in June 1971,I gave a series of lectures at Saha Institute of Nuclear Physics on the gauge theory of weak interactions. Those lectures contained Yang-Mills theory, Faddev-Popov ghosts, Higgs mechanism, electroweak theory, and Glashow-Iliopoulos-Maiani mechanism to remove strangeness=changing neutral current. This came out as a SINP report. This was the first connected account of all the aspects of what became known as the Standard Model. It even contained my conjecture that because of infrared divergences of Yang-Mills theory, massless YM quantum cannot exist. This idea later on became the basis of infrared slavery and colour confinement of QCD.
It is after my SINP lectures, that t'Hooft published his paper on the the proof of renormalizability of the electroweak gauge theory.
After that, Gross, Wilkzek and Politzer discovered that Yang-mills theory has asymptotic freedom and Gell-Mann, Fritsche and Leutwyler proposed color gauge theory as the theory of strong interactions. This was QCD.
Renomalizability of electroweak theory and asymptotic freedom are the the two important discoveries in quantum field theory after the discovery of renormalizability of quantum electrodynamics in 1947-48. Although I had full opportunities to make these discoveries, I missed them!
One reason for this was that I was on a wrong path at that time. I was trying to generate the strong interactions from the divergences in Wienberg's electroweak theory.
I was well aware of the path integral techniques used by t'Hooft.
Even before the papers of Gross, Wilkzek and Politzer came, I was giving lectures at TIFR on renormalization group and Callan-Symanzig equations which were used in the discovery of asymptotic freedom.
Although I did not succeed, I was very near success. When the discoveries came fast, I could recognize their importance immediately.
India-based Neutrino Observatory (INO)
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India was a pioneer in neutrino research. Neutrinos from cosmic rays were first detected at Kolar Gold Fields in 1964. But in the 1990's the gold mines were closed since there was not enough gold. We must have prevented the closure. "Scientific truth is more valuable than gold."
Using the same cosmic-ray-produced neutrinos in research, Japanese scientists got Nobel Prize in 1998 and 2002. We lost the opportunity.
Can we recover this lost opportunity? Yes, we can. That is the aim of the INO project.
In the year 2001, we started this project. Government of India allocated Rs 1600 crores for it.
The neutrino detector will be made of magnetised iron and resistive plate chambers and will weigh 50,000 tons. This will be installed in a cavern dug inside a mountain Theni district and will be used to study the cosmic-ray-produced neutrinos.
The main nerve-centre of INO will be established on the outskirts of Madurai. In this, detector R & D and student training will be conducted.
This has been named Inter-Institutional Centre for High Energy Physics and it is already functioning at a transit campus.
Some "wise people" from Tamil Nadu have been spreading lies abut INO and claiming INO will be dangerous. They have succeeded in stopping the progress of INO. But they cannot stop it permanently. "Truth will prevail."
A challenge in Fundamental Physics
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The three basic forces of Nature, electromagnetic, weak and strong forces are contained in the Standard Model based on Yang-Mills theory. Standard Model leaves out gravitational force. Gravitation which becomes curvature of space-time in Einstein's General Theory of Relativity refuses to be described by quantum mechanics. So, Quantum Gravity has become a challenge in Fundamental Physics.
String Theory has been found to be the correct theory for quantum gravity.
But String Theory has not been confirmed by any experiment. To confirm the Standard Model experimentally, it took 40 years. For that purpose, accelerators with higher and higher energies were constructed and finally, the Large Hadron Collider (LHC) of had to be built. This LHC which is in CERN, Geneva is a behemoth; it is a circle of 28 Km circumference.
The energy required to experimentally test string theory is which is times higher than that of LHC. Most scientists think that it is impossible to build such an accelerator. This is a crisis in Fundamental Physics.
There is no limit to human ingenuity. Human brain is capable of crossing this obstacle.
New methods of particle acceleration must be found. In any case, if new methods are not found, there will be an end to Fundamental Research by about 2040. For the accelerator technology used upto now will not be useful beyond about
In the past 80 years, the energy of accelerators grew substantially. It increased by a factor of 10, every 6 years. This growth is a good sign for the future of Fundamental Physics.
If this rate of growth continues, a factor of will be achieved in 15 x 6 = 90 years. Some may consider this as too long, but that is wrong. It took 40 years to test Standard Model.
But such a growth is possible only if new ways and new technologies continue to be discovered.
For many years, I have been stressing that our country must embark on research into new accelerator technologies.
What are the new ways? I will mention one way here. In the past 40 years, many new ideas have been developed about Laser Plasma Acceleration (LPA).
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Using the plasma wake fields generated by laser, they have succeeded in accelerating electrons to in a distance of 1 centimeter. In the conventional accelerators this would require 1 kilometer.
LPA alone will not take us to , but LPA will be an important step to reach that goal.
Our country must start this LPA research. I have been discussing this with many laser and plasma scientists in the research institutions in India.
There are two immediate steps that must be taken:
1. A task force for LPA must be formed.
2. An LPA centre must be created.
For the success of this venture, we need the help and cooperation of scientists from other countries. In December 2014, an International Conference on high-power lasers was held at Goa. The enormous growth of LPA research became clear in this meeting. It also became clear that if we take up the LPA challenge now, we will get international support.
So we must not lose this opportunity.
This big project is possible only with the support of the Government. This is a big dream. Scientific advance of our country is possible only through such big dreams.
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