計算物性物理メーリングリストのみなさま
東京大学の大久保です。
6/23に下記の内容で統計力学セミナーを開催します。
対面とオンラインのハイブリッドで、学外の方も、オンラインで参加できます。
参加をご希望の方は大久保
t-okubo@phys.s.u-tokyo.ac.jp
までご連絡ください。
折り返し、Zoomの接続情報を送ります。
大久保 毅
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統計力学セミナー StatPhys Seminar @ UTokyo Hongo
sites.google.com/view/statphys-seminar
Room: 理学部1号館206教室 (Room No. 206, Science 1st Bldg.) and Online(Zoom)
Speaker: 岩木惇司（東大）, Atsushi Iwaki (The University of Tokyo)
Title: Random sampling for thermal quantum states
Abstract:
A given quantum state in a thermal equilibrium always has a facultativity in the way how they are described at the microscopic level. The two limiting cases are the Gibbs state which is the exponentially large number of mixtures of pure states with zero purity, and the thermal pure quantum (TPQ) state which is a single quantum state with purity-1. Here, we propose a series of thermal mixed quantum (TMQ) states that have purity between 0 and 1 [1]. We regard all of them as describing the same thermal equilibrium in the sense that they are indistinguishable if we focus on the local observables or the density matrix of a relatively large but small enough subsystem. In this work, we develop an analytical formulation to describe the purity of the TMQ state generated by random samplings. We apply this formula to the TPQ-MPS method [2] and the RPMPS+T method [3], demonstrating that the purity can be measured and can explain the features of these methods. In addition, we will introduce recen
t analytical results on the sample complexity of the TPQ-MPS method.
[1] A. Iwaki and C. Hotta, PRB 106, 094409 (2022).
[2] A. Iwaki, A. Shimizu, and C. Hotta, PRResearch 3, L022015 (2021).
[3] S. Goto, R. Kaneko, and I. Danshita, PRB 104, 045133 (2021).
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大久保 毅
東京大学大学院理学系研究科 量子ソフトウェア寄付講座
特任准教授
〒113-0033 東京都文京区本郷7-3-1
東京大学大学院理学系研究科知の物理学研究センター
理学部1号館9階 950
e-mail: t-okubo@phys.s.u-tokyo.ac.jp
Tel: 03-5841-8890
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