Sibaji Raha

There is a famous quote from Einstein – “The strangest thing about the Universe is that it is understandable”. The human intellect understands the Universe through scientific investigations, explorations and logic; no part of it, however large or small, escapes our attention and our quest for the physical laws governing all aspects of the Universe comprises the ultimate intellectual endeavour.

Over the past several decades, the consensus has emerged that there are four types of fundamental interactions in Nature, which explain all the physical processes occurring in the Universe. The extremely short-range strong force operates between quarks and gluons, the fundamental constituents of atomic nuclei; the weak force too is short-range, but much weaker in strength compared to the strong force. It can change the electromagnetic charge of particles, leading to the phenomenon of radioactivity. The electromagnetic force is of infinite range, governing chemical and atomic interactions, thus dominating the processes of everyday life. The fourth force is the gravitational interaction, responsible for planetary, stellar, galactic and supergalactic dynamics, the science of the very large.

The strong, the electromagnetic and the weak forces all have an underlying quantum field theoretical framework, called gauge theories; for gravitation, however, a consistent quantum theory still eludes us. Arriving at such a theory and combining all the four interactions within one consistent quantum theory is the holy grail of physics…read more on NOPR