Jethalal S. Zaveri
Prof. Muni Mahendra Kumar
In 1967, theories for unifying the electromagnetic force and weak nuclear force were proposed by Abdus Salam and Steven Weinberg, just as Maxwell had unified electricity and magnetism about a hundred years earlier. They suggested that in addition to photon, there were three other 'spin 1' particles, known collectively as "massive vector bosons" that carried weak force. Each had a mass of around 100 Gev. (Gev. stands for giga-electron-volt or 1000 million electron volt.) At energies much greater than 100 Gev the three new particles and the photon would all behave in-a similar manner. Particle-accelerators were not powerful enough to reach the energies of 100 Gev. at that time. But over the next 10 years or so, the other predictions of the theories at lower energies agreed so well with experiment that in 1979, Salam and Weinberg were awarded Nobel Prize for Physics together with Sheldon Glashow who had suggested similar unified theories of the electromagnetic and weak nuclear forces. In 1983, the three massive partners of photon were discovered at ECNR (European Centre for Nuclear Research) in Switzerland.
The success of the unification of the electromagnetic and weak nuclear forces led to a number of attempts to combine these two forces with the strong nuclear force. The basic idea is: At high energies, the strong nuclear force gets weaker (as mentioned earlier), while the other two forces which are not 'asymptotically' free, get stronger. At some very high energy called the 'grand unification energy,' these three forces would all have the same strength and so could just be different aspects of a single force. It is also predicted that at this energy (at least a thousand million Gev), the different 'spin-1/2' matter- particles like quarks and electrons would also all be essentially the same, thus achieving unification.
At 'grand unification energy', there is no essential difference between a quark and a positron (anti-electron). There is, thus, a possibility of spontaneous decay of protons, which make up the most of the mass of ordinary matter, into lighter particles such as positrons. 'Grand Unified Theories' (GUT) do not include the force of gravity. This does not matter too much, because gravity is such a weak force that its effects can usually be neglected when we are dealing with microcosms i.e., sub-atomic particles, or atoms. However, the fact that it is both long range and always attractive means that its effects all add up. So, for a sufficiently large number of matter-particles, gravitational forces can dominate over all other forces. This is why it is gravity that determines the evolution of the Universe. For macrocosms i.e., objects of the size of stars, gravity can win over all the other forces and cause the star to collapse. (See, "Nuclear Transformation in Nature" in the last Section of this Chapter.) Already there are first hints of a quantum theory of gravity yet to come.
Since the postulation of quark in 1968, quarter of a century has passed during which a spate of new theories-S-matrix, bootstrap, Bell's theorem, quantum field theories, quantum electrodynamics, Gauge theory etc. have appeared in the field. All these are too complicated, though relevant for discussion in the present book. In the meantime physicists have become philosophers, as was the case 2500 years ago. For instance, according to Geoffrey Chew, who is the originator of the bootstrap idea and has been the unifying force and philosophical leader in S-matrix theory for the past two decades, the extension of bootstrap approach beyond hadrons may lead to the possibility of being forced to include the study of human consciousness.
Since he wrote these words, almost twenty years ago, the new developments have brought them (the physicists and philosophers), considerably close to dealing with consciousness explicitly. David Bohm has perhaps gone further than anybody else in studying the relations between consciousness and matter in a scientific context. We shall further discuss this phenomenon of reversing the Cartesian division in the succeeding section.
