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TT: Fachverband Tiefe Temperaturen

TT 25: Nonequilibrium Quantum Systems I (joint session TT/DY)

TT 25.6: Talk

Tuesday, March 19, 2024, 10:45–11:00, H 3005

Few-body purity as an arrow of time in the Lanczos picture — •Merlin Füllgraf and Jochen Gemmer — Department of Mathematics/Computer Science/Physics, University of Osnabrück, D-49076 Osnabrück, Germany

The Lanczos method to compute autocorrelation functions in quantum mechanics gives rise to so-called Lanczos coefficients associated with operator growth in the respective systems. These coefficients can be interpreted as hopping amplitudes of a semi-infinite tight-binding model whose first site corresponds to the correlation function itself. In this picture we introduce a few-body purity and study it against the background of an arrow of time. Moreover, we investigate the influence of structures in the Lanczos coefficients on this quantity and propose a qualitative model solely based on these coefficients describing their influence on the systems’ dynamics.

[1] D.E. Parker, X. Cao, A. Avdoshkin, T. Scaffidi, E. Altman, Phys. Rev. X 9 (2019) 041017

[2] V.S. Viswanath, G. Müller, The Recursion Method: Applications to Many-Body Dynamics, Springer, New York (2008).

Keywords: Quantum dynamics; Arrow of time