Glimmers of a pre-geometric perspective

TL;DR

This paper explores how space-time concepts can emerge from the information exchange between matter fields in quantum models, suggesting a pre-geometric foundation for space-time.

Contribution

It introduces a framework to derive space-time relations from matter field interactions and tensor product structures, highlighting differences between free and interacting theories.

Findings

Free theories lack operational space-time relations.

Interacting models like the Heisenberg spin chain recover position-based tensor structures.

Gravity's role is discussed in the context of emergent space-time.

Abstract

Space-time measurements and gravitational experiments are made by using objects, matter fields or particles and their mutual relationships. As a consequence, any operationally meaningful assertion about space-time is in fact an assertion about the degrees of freedom of the matter (\emph{i.e} non gravitational) fields; those, say for definiteness, of the Standard Model of particle physics. As for any quantum theory, the dynamics of the matter fields can be described in terms of a unitary evolution of a state vector in a Hilbert space. By writing the Hilbert space as a generic tensor product of "subsystems" we analyse the evolution of a state vector on an information theoretical basis and attempt to recover the usual space-time relations from the information exchanges between these subsystems. We consider generic interacting second quantized models with a finite number of fermionic degrees of freedom and characterize on physical grounds the tensor product structure associated with the class of "localized systems" and therefore with "position". We find that in the case of free theories no space-time relation is operationally definable. On the contrary, by applying the same procedure to the simple interacting model of a one-dimensional Heisenberg spin chain we recover the tensor product structure usually associated with "position". Finally, we discuss the possible role of gravity in this framework.