Scattering symmetry of diffusive systems

Abstract

Significant progress in manipulating heat diffusion has been achieved with the advent of non-Hermitian physics and topology. However, previous studies on diffusive systems have primarily concentrated on isolated cases, where fields decay exponentially over time. In practical scenarios, systems inevitably interact with external environments, making it essential to study their responses to external heat signals. This, in turn, relies on analyzing the scattering behavior of these signals. In our work, we experimentally realize thermal scattering in a diffusive anti-parity-time (APT) system. We define key parameters of the temperature field-amplitude, phase, and chirality-and reveal that the scattering symmetry of the APT diffusive system only arises when temperature signals with different chiralities interact. Such mechanism is induced by the unique dispersion properties in diffusive systems, where positive and negative frequencies are inequivalent, corresponding to different chiralities. This also explains the difficulty of observing APT scattering symmetry in wave systems. Our findings highlight the pivotal role of scattering channels in the symmetry and phase transitions of non-Hermitian systems and propose novel approaches for analyzing and controlling strongly dissipative phenomena.

References in corpus (13)

• Unidirectional Invisibility induced by PT-Symmetric Periodic Structures
• Exceptional Topology of Non-Hermitian Systems
• Non-Hermitian Physics
• PT-symmetry breaking and laser-absorber modes in optical scattering systems
• Transforming heat transfer with thermal metamaterials and devices
• Controlling mass and energy diffusion with metamaterials
• Parity-Time Symmetry in Non-Hermitian Complex Optical Media
• Tunable liquid-solid hybrid thermal metamaterials with a topology transition
• Localized heat diffusion in topological thermal materials
• Diffusive non-reciprocity and thermal diode
• $\mathcal{P}\mathcal{T}$ symmetry breaking in waveguide arrays with competing loss/gain pairs
• Systematic pathway to $\mathcal{P}\mathcal{T}$ symmetry breaking in scattering systems
• Chiral and non-chiral swift mode conversion near an exception point with dynamic adiabaticity engineering