Non-Hermitian Discrete Time Crystals

• Main Authors: Yousefjani, Rozhin, Carollo, Angelo, Sacha, Krzysztof, Al-Kuwari, Saif, Bayat, Abolfazl
• Format: Journal Article
• Language: English
• Published: 30-10-2024
• Subjects: Physics - Quantum Physics
• DOI: 10.48550/arxiv.2410.22713

Discrete time crystals (DTC) exhibit a special non-equilibrium phase of
matter in periodically driven many-body systems with spontaneous breaking of
time translational symmetry. The presence of decoherence generally enhances
thermalization and destroys the coherence required for the existence of DTC. In
this letter, we devise a mechanism for establishing a stable DTC with
period-doubling oscillations in an open quantum system that is governed by a
properly tailored non-Hermitian Hamiltonian. We find a specific class of
non-reciprocal couplings in our non-Hermitian dynamics which prevents
thermalization through eigenstate ordering. Such choice of non-Hermitian
dynamics, significantly enhances the stability of the DTC against imperfect
pulses. Through a comprehensive analysis, we determine the phase diagram of the
system in terms of pulse imperfection.