Honorary faculty, I-SERVE
Alakapuri, Hyderabad-35, India
Prof. S. Lakshminarayana
Dept. of Nuclear Physics, Andhra University
Unification means: finding the similarities, finding the limiting physical constants, finding the key numbers, coupling the key physical constants, coupling the key physical concepts, coupling the key physical properties, minimizing the number of dimensions, minimizing the number of inputs and implementing the key physical constant or key number in different branches of physics.
This is a very lengthy process. In all these cases observations, interpretations, experiments and imagination play a key role. The main difficulty is with interpretations and observations.
As the interpretation changes physical concept changes, physical equation changes and finally the destiny changes.
Universe is a very big laboratory and its life span is very large. Modern physics is having only and hardly 200 years of strong scientific background. Strong motivation, good reasoning, nature friendly concepts, simplicity and applicability are the most favorable and widely accepted qualities of any new model.
Note that in the atomic or nuclear physics, till today no one measured the gravitational force of attraction between the proton and electron and experimentally noone measured the value of the gravitational constant.
Physicists say, if strength of strong interaction is unity, with reference to the strong interaction, strength of gravitation is 10^-39. The fundamental question to be answered is: is mass an inherent property of any elementary particle?
To unify 2 interactions if 5 dimensions are required, for unifying 4 interactions 10 dimensions are required. For 3+1 dimensions if there exists 4 (observed) interactions, for 10 dimensions there may exist 10 (observable) interactions. To unify 10 interactions 20 dimensions are required. From this idea it can be suggested that with ‘n’ new dimensions ‘unification’ problem can not be resolved.
As the culmination of his life work, Einstein wished to see a unification of gravity and electromagnetism as aspects of one single force. In modern language he wished to unite electric charge with the gravitational charge (mass) into one single entity. Further, having shown that mass the ‘gravitational charge’ was connected with space-time curvature, he hoped that the electric charge would likewise be so connected with some other geometrical property of space-time structure. For Einstein the existence, the mass, the charge of the electron and the proton the only elementary particles recognized back in 1920s were arbitrary features. One of the main goals of a unified theory should explain the existence and calculate the properties of matter.
Stephen Hawking – in his famous book – says: It would be very difficult to construct a complete unified theory of everything in the universe all at one go. So instead we have made progress by finding partial theories that describe a limited range of happenings and by neglecting other effects or approximating them by certain numbers. (Chemistry, for example, allows us to calculate the interactions of atoms, without knowing the internal structure of an atomic nucleus). Ultimately, however, one would hope to find a complete, consistent, unified theory that would include all these partial theories as approximation, and that did not need to be adjusted to fit the facts by picking the values of certain arbitrary numbers in the theory. The quest for such a theory is known as “the unification of physics”.
Einstein spent most of his later years unsuccessfully searching for a unified theory, but the time was not ripe: there were partial theories for gravity and the electromagnetic force, but very little was known about the nuclear forces. Moreover, Einstein refused to believe in the reality of quantum mechanics, despite the important role he had played in its development.
The first step in unification is to understand the origin of the rest mass of a charged elementary particle. Second step is to understand the combined effects of its electromagnetic (or charged) and gravitational interactions. Third step is to understand its behaviour with surroundings when it is created. Fourth step is to understand its behaviour with cosmic space-time or other particles. Right from its birth to death, in all these steps the underlying fact is that whether it is a strongly interacting particle or weakly interacting particle, it is having some rest mass. To understand the first 2 steps somehow one must implement the gravitational constant in sub atomic physics.