Topological localization in time from parity-time symmetry
File(s)
Published version (corrected proof)
Author(s)
Type
Journal Article
Abstract
Time has entered the domain of topological phases in the field of non-Hermitian physics. Previous studies have relied on periodic modulation in time to make an intuitive connection to established spatial topological invariants, albeit with energy and momentum exchanged. This connection has revealed the potential for topological interface states along the time axis, analogous to those in spatial models. In this work, we uncover a theoretical framework describing such topological interface states along the time axis, with no underlying connection to spatial models nor need for periodic driving. This new framework uncovers that this phenomenon—the robust localization of waves at an interface—appears in every system that has parity-time symmetry and two coupled modes or bands, regardless of its spatial dimensionality. The topological nature of this localization is understood by the identification of certain topological phases that are specific to parity-time-symmetric models of two coupled modes. Our theoretical framework can be applied to all existing experimental observations, notably including photonic time crystals, and serves as a foundation for future experiments in areas in which the topological localization of waves in time has yet to be studied.
Date Issued
2026-07-31
Date Acceptance
2026-07-07
Citation
Newton, 2026
ISSN
2950-6360
Publisher
Elsevier BV
Journal / Book Title
Newton
Copyright Statement
© 2026 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published online
Article Number
100622
Date Publish Online
2026-07-31