Variational quantum simulation of the quantum critical regime
- URL: http://arxiv.org/abs/2302.07438v1
- Date: Wed, 15 Feb 2023 02:59:41 GMT
- Title: Variational quantum simulation of the quantum critical regime
- Authors: Zhi-Quan Shi, Xu-Dan Xie, Dan-Bo Zhang
- Abstract summary: We propose a variational approach, which minimizes the variational free energy, to simulate and locate the quantum critical regime on a quantum computer.
Our work suggests a practical way as well as a first step for investigating quantum critical systems at finite temperatures on quantum devices with few qubits.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: The quantum critical regime marks a zone in the phase diagram where quantum
fluctuation around the critical point plays a significant role at finite
temperatures. While it is of great physical interest, simulation of the quantum
critical regime can be difficult on a classical computer due to its intrinsic
complexity. In this paper, we propose a variational approach, which minimizes
the variational free energy, to simulate and locate the quantum critical regime
on a quantum computer. The variational quantum algorithm adopts an ansatz by
performing an unitary operator on a product of a single-qubit mixed state, in
which the entropy can be analytically obtained from the initial state, and thus
the free energy can be accessed conveniently. With numeral simulation, we show,
using the one-dimensional Kitaev model as a demonstration, the quantum critical
regime can be identified by accurately evaluating the temperature crossover
line. Moreover, the dependence of both the correlation length and the phase
coherence time with the temperature are evaluated for the thermal states. Our
work suggests a practical way as well as a first step for investigating quantum
critical systems at finite temperatures on quantum devices with few qubits.
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