Two-Time Physics

By Itzhak Bars
University of Southern California

Edited by Andy Ross

According to 2T-physics, additional dimensions, one of space and one of time, can coexist with the familiar 3+1 dimensions. There are gauge symmetries that effectively reduce 2T-physics in 4+2 dimensions to 1T-physics in 3+1 dimensions.

To grasp the relation between 1T-physics and 2T-physics, consider the many possible shadows of a 3-dimensional object projected from different perspectives on the surrounding walls of a 3-dimensional room. Similarly, according to 2T-physics, a unique dynamical system in 4+2 dimensions generates a large variety of 1-time shadows, and 1T-physics presents these shadows in 3+1 dimensional space-times as different dynamical systems in terms of different times.

In this way, 1T-physics misses the underlying relationship between the shadows as well as the underlying properties of the higher dimensional space-time. But 2T-physics provides the missing information to show that indeed the d+2 structure of space-time governs all levels of physics, from macroscopic to microscopic scales, in classical and quantum systems, including the fundamental physics of the Standard Model, and beyond.

The permitted motions in 4+2 phase space are highly symmetrical, as they are constrained by a gauge symmetry that makes momentum and position indistinguishable at any instant. Such symmetric motions in 4+2 dimensions are compatible with the way physics is perceived in 3+1 dimensions. There are no problems with causality or unitarity because the extra 1+1 space-time is removable by the gauge symmetry.

One result of this new gauge principle is that it requires the theory to be formulated in a spacetime having at least two times. While taking exactly two timelike dimensions produces a coherent theory, investigations of alternatives so far rule them out, which seems to confirm the special status of 2T-physics.

Recently, a field theoretic description of 2T-physics has been established. Amazingly, the best understood fundamental theory in physics, the Standard Model (SM) in 3+1 dimensions, is reproduced as one of the shadows of a parent field theory in 4+2 dimensions. Among the successes of the emergent SM is the resolution of the strong CP problem of QCD due to the more constraining structure of the underlying 4+2 theory. The emergent SM agrees with all aspects that actually work experimentally so far in the usual SM.

The field theoretic studies of 2T-physics have been generalized to supersymmetric field theory. The more constraining structure of the underlying 4+2 theory is expected to have phenomenological consequences that could help to distinguish 2T-physics from other approaches in experiments at the LHC starting in 2008, if supersymmetry is found experimentally at the TeV scale.

The results have established that 2T-physics is a structure that correctly describes, at least in principle, all the physics we have understood up to now. But 2T-physics also suggests the existence of new relationships and new phenomena.
 

Itzhak Bars is a professor in the Department of Physics at the University of Southern California: "My current interests include String Field Theory (SFT), and Two-Time Physics (2T-Physics). My long term goal is the construction of the unified M-theory at the fundamental level. In 2006 I have established that all the physics we know today, as embodied in principle in the Standard Model of Particles and Forces, is described by a gauge fixed version of 2T-physics in 4 space and 2 time dimensions. My research is driven by some of the current questions in Cosmology, the Standard Model of elementary particles, and unification of forces including quantum gravity."