Quantum Field Theories in Spaces with Neutral Signatures

TL;DR

This paper explores quantum field theories in Clifford spaces with neutral signatures, showing that such theories can have vanishing vacuum energy and potentially stable interactions, addressing the cosmological constant problem.

Contribution

It introduces a toy model of harmonic oscillators in neutral signature space and demonstrates conditions for stability and finite amplitudes, extending to field theories.

Findings

Vacuum energy vanishes in neutral signature Clifford spaces

Oscillator amplitudes remain finite under certain interactions

Stability depends on frequency differences in the model

Abstract

We point out that quantum field theories based on the concept of Clifford space and Clifford algebra valued-fields involve both positive and negative energies. This is a consequence of the indefinite signature (p,q) of the Clifford space. When the signature is neutral, p=q, then vacuum energy vanishes and there is no cosmological constant problem. A question of the stability of such theories in the presence of interactions arises. We investigate a toy model of the harmonic oscillator in the space $M_{1,1}$. We have found that in the presence of certain interactions the amplitude of oscillations can remain finite. In general this is not the case and the amplitude grows to infinity, but only when the two frequencies are exactly the same. When they are even slightly different, the amplitude remains finite and the system is stable. We show how such oscillator comes from the Stueckelberg action in curved space, and how it can be generalized to field theories.