Speaker
Description
There is a range of interesting physical scenarios that include both many-body quantum systems and strongly coupled structured environments that lead to a non-Markovian evolution. However, almost all methods for the study of many-body systems only consider closed or Markovian dynamics, while methods for the study of non-Markovian open quantum systems are generally restricted to small system sizes. I will introduce a general numerical method to compute dynamics and multi-time correlations of chains of quantum systems, where each system may couple strongly to a structured environment [1,2]. The method combines the process tensor formalism for general (possibly non-Markovian) open quantum systems with time evolving block decimation (TEBD) for 1D chains. It systematically reduces the numerical complexity originating from system-environment correlations before integrating them into the full many-body problem, making a wide range of applications numerically feasible. Furthermore, on a more conceptional side, I will discuss fundamental connections among the concept of Markovianity, multi-time correlations, and the dynamics of a many-body open quantum system [3]. These connections not only have far reaching consequences in, for example, the field of strong coupling quantum thermodynamics, but also in many-body scenarios that are usually considered to be Markovian in the literature.
[1] G. E. Fux, D. Kilda, B. W. Lovett, and J. Keeling, Thermalization of a spin chain strongly coupled to its environment, arXiv:2201.05529 (2022).
[2] The TEMPO Collaboration, OQuPy: A Python 3 package to efficiently compute non-Markovian open quantum systems, ReadTheDocs (2020).
[3] G. E. Fux, Operationally accessible information backflow in CP-divisible processes, in preperation.
| Abstract category | Numerical Methods |
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