# Temporal Anti-Parity–Time Symmetry: Extending Non-Hermitian Physics to Time-Domain Dynamics in Thermal Diffusion

## TL;DR

This paper introduces a new concept in physics that allows for time-based control of symmetry in diffusive systems, expanding beyond static configurations.

## Contribution

The paper introduces and verifies temporal anti-parity–time symmetry in diffusive systems, enabling dynamic control of energy transport in the time domain.

## Key findings

- Temporal anti-parity–time symmetry has been demonstrated in diffusive media.
- Energy transport in such systems can be actively programmed over time.
- This extends non-Hermitian physics to time-domain dynamics in thermal diffusion.

## Abstract

Parity–time and anti-parity–time symmetries, originally formulated in the context of non-Hermitian quantum mechanics, have now been experimentally realized across diverse physical platforms, including photonic, wave-guiding, acoustic, and mechanical systems, as well as systems operating near exceptional points. While the active manipulation of these symmetries has been well explored in wave-based systems, their implementations in diffusive physics have long remained predominantly confined to static phases, where systems are locked in a fixed symmetric or symmetry-broken configuration due to their invariant structural parameters. Bridging this gap, recent work has introduced and verified the concept of temporal anti-parity–time symmetry, demonstrating that energy transport in diffusive media can be actively programmed in the time domain.