Quantum mechanics without spacetime II : noncommutative geometry and the free point particle

TL;DR

This paper proposes a background-independent formulation of quantum mechanics using noncommutative geometry, generalizing the concept of diffeomorphism invariance, and applies it to the free point particle, connecting it to quantum gravity.

Contribution

It introduces a noncommutative geometric framework for quantum mechanics that does not rely on spacetime, extending automorphism invariance to include coordinate transformations.

Findings

The formulation is invariant under automorphisms that generalize diffeomorphisms.

It reduces to standard quantum mechanics when a spacetime manifold exists.

Provides a quantum gravitational perspective for the free particle.

Abstract

In a recent paper we have suggested that a formulation of quantum mechanics should exist, which does not require the concept of time, and that the appropriate mathematical language for such a formulation is noncommutative differential geometry. In the present paper we discuss this formulation for the free point particle, by introducing a commutation relation for a set of noncommuting coordinates. The sought for background independent quantum mechanics is derived from this commutation relation for the coordinates. We propose that the basic equations are invariant under automorphisms which map one set of coordinates to another- this is a natural generalization of diffeomorphism invariance when one makes a transition to noncommutative geometry. The background independent description becomes equivalent to standard quantum mechanics if a spacetime manifold exists, because of the proposed automorphism invariance. The suggested basic equations also give a quantum gravitational description of the free particle.