Theory Seminar: Markovian regimes in Quantum Many Body Systems

Julian Roos (MPQ)
Long time evolution of the full state of quantum many body systems is generally out of reach due to build-up of entanglement.

Julian Roos (MPQ)
Herbert-Walther Lecture Hall G0.25 (MPQ)
Wed, 4. March 2020, 11:30 am

Abstract:  

Long time evolution of the full state of quantum many body systems is generally out of reach due to build-up of entanglement. However, the computation of local observables only requires knowledge of the state of (small) subsystems. Is it possible to obtain a description of the reduced dynamics similarly to what is done in the fields of Quantum Optics and Open Quantum Systems (OQS)? We expect that such an endeavour is most promising in the simplest case, i.e. when the dynamics are Markovian (memoryless), and we thus study if such regimes do also exist in a many body setup. Here, the conditions that allow for the derivation of a Markovian master equation in the theory of OQS (Born-Markov) are not satisfied. In this talk I thus adopt a Quantum Information Theory perspective to identify interesting Markovian regimes (of a spin coupled to a XY spin chain) and explain the underlying physics responsible for Markovian/non-Markovian dynamics. arXiv:1912.09151