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Defining a quantum active particle using a non-unitary quantum walk

日程 : 2023年11月28日(火) 16:00 - 17:00 場所 : Seminar Room 5 (A615), Hybrid 講師 : Manami Yamagishi 所属 : Department of Physics, The University of Tokyo; RIKEN 世話人 : Kohei Kawabata (63270)講演言語 : 英語

The main aim of the present work is to define an active matter in a quantum framework and investigate difference and commonalities of quantum and classical active matters. We here propose a truly deterministic quantum active-matter model with a non-unitary quantum walk as minimal models of quantum active matter [1]. We aim to reproduce similar results that Schweitzer et al. (1998) obtained with their classical active Brownian particle [2]. With our quantum active particle, we successfully observe that the movement of the quantum walker becomes more active in a non-trivial way as we increase the non-Hermiticity parameter, which is similar to the classical active Brownian particle (Schweitzer et al., 1998). Meanwhile, we also observe three unique features of quantum walks, namely, ballistic propagation of peaks in one dimension, the walker staying on the constant energy plane in two dimensions, and oscillations originating from the resonant transition between the ground state and excited state both in one and two dimensions. I also plan to explain more technical sides of quantum walks in higher dimensions [3] and with interactions [4] if time allows.

[1] M. Yamagishi, N. Hatano and H. Obuse, arXiv:2305.15319 (2023).
[2] F. Schweitzer, W. Ebeling and B. Tilch, Phys. Rev. Lett. 80, 5044 (1998).
[3] M. Yamagishi, N. Hatano, K.-I. Imura and H. Obuse, Phys. Rev. A 107, 042206 (2023).
[4] M. Yamagishi, N. Hatano, A. Nishino, F. Nori and H. Obuse, in preparation.


(公開日: 2023年11月02日)