Abstract
Spin chains with open boundaries, such as the transverse field Ising model, can display coherence times for edge spins that diverge with the system size as a consequence of almost conserved operators, the so-called strong zero modes. Here, we discuss the fate of these coherence times when the system is perturbed in two different ways. First, we consider the effects of a unitary coupling connecting the ends of the chain; when the coupling is weak and non-interacting, we observe stable long-lived harmonic oscillations between the strong zero modes. Second, and more interestingly, we consider the case when dynamics becomes dissipative. While in general dissipation induces decoherence and loss of information, here we show that particularly simple environments can actually enhance correlation times beyond those of the purely unitary case. This allows us to generalise the notion of strong zero modes to irreversible Markovian time-evolutions, thus defining conditions for {\em dissipative strong zero maps}. Our results show how dissipation could, in principle, play a useful role in protocols for storing information in quantum devices.
Highlights
Recent results have demonstrated the possibility of observing in many-body quantum chains with open boundary conditions coherence times for edge spins that diverge exponentially with the size of the system [1,2,3,4,5,6]
While robustness of coherence times for edge spins has been extensively studied in the presence of interactions or of integrability-breaking terms and in the presence of disorder in the Hamiltonian [1, 2, 19], less is known about their behavior under irreversible open quantum dynamics [20,21,22,23,24]
Understanding the behavior of these time-correlations in open quantum systems would allow for the possibility of exploiting the protected information encoded in edge spins for applications in quantum devices in realistic non-equilibrium settings
Summary
Recent results have demonstrated the possibility of observing in many-body quantum chains with open boundary conditions coherence times for edge spins that diverge exponentially with the size of the system [1,2,3,4,5,6]. While robustness of coherence times for edge spins has been extensively studied in the presence of interactions or of integrability-breaking terms and in the presence of disorder in the Hamiltonian [1, 2, 19], less is known about their behavior under irreversible open quantum dynamics [20,21,22,23,24] It is not clear whether under Markovian (memory-less) dynamics these long edge time-correlations can be observed and general conditions for their existence are not known. These are obtained exploiting the possible presence of symmetry sectors in the dynamical generator of the open quantum dynamics [28, 29]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
