Quantum state complexity and the thermodynamic arrow of time

TL;DR

This paper explores the hypothesis that the thermodynamic arrow of time is driven by increasing quantum state complexity, supported by studies on two- and three-qubit systems showing a correlation between complexity and time's direction.

Contribution

It provides empirical evidence linking quantum state complexity to the thermodynamic arrow of time in small quantum systems, suggesting a fundamental origin.

Findings

In two-qubit systems, time always progresses with increasing quantum complexity.

In three-qubit systems, heat flow correlates with the quantum complexity of subsystems.

Quantum state complexity may influence the thermodynamic arrow beyond macroscopic geometry.

Abstract

Why time is a one-way corridor? What's the origin of the arrow of time? We attribute the thermodynamic arrow of time as the direction of increasing quantum state complexity. Inspired by the work of Nielsen, Susskind and Micadei, we checked this hypothesis on both a simple two qubit and a three qubit quantum system. The result shows that in the two qubit system, the thermodynamic arrow of time always points in the direction of increasing quantum state complexity. For the three qubit system, the heat flow pattern among subsystems is closely correlated with the quantum state complexity of the subsystems. We propose that besides its impact on macroscopic spatial geometry, quantum state complexity might also generate the thermodynamic arrow of time.