Quantum Theory, Gravity, and the Standard Model of Particle Physics
- Using the hints of today to build the nal theory of tomorrow -
When a mountaineer is ascending one of the great peaks of the Himalayas she knows that an entirely new vista awaits her at the top, whose rami cations will be known only after she gets there. Her immediate goal though, is to tackle the obstacles on the way up, and reach the peak. In a similar vein, one of the immediate goals of contemporary theoretical physics is to build a quantum, uni ed description of general relativity and the standard model of particle physics. Once that peak has been reached, a new (yet unknown) vista will open up. In this essay I propose a novel approach towards this goal. One must address and resolve a fundamental unsolved problem in the presently known formulation of quantum theory : the unsatisfactory presence of an external classical time in the formulation. Solving this problem takes us to the very edge of theoretical physics as we know it today!
Modern physics can be said to have begun with the work of Kepler, Galileo and Newton, when the classical laws of motion of bodies were laid down, and the law of gravitation was discovered. The next major development in theoretical physics was Maxwell's theory for the electromagnetic eld, and the realization that light is an electromagnetic wave, which travels through vacuum at a universal speed. The inconsistency of this latter result with Newton's mechanics led to the special theory of relativity, and in turn, the incompatibility of special relativity and Newtonian gravitation saw the arrival of the general theory of relativity. Side by side, the failure of classical physics to explain observed phenomena such as the black-body spectrum of electromagnetic radiation, the photo-electric e ect, and the spectra of atoms, heralded the discovery of the laws of quantum mechanics. Over the...