Probing Off-diagonal Eigenstate Thermalization with Tensor Networks

• URL: http://arxiv.org/abs/2312.00736v3
• Date: Tue, 2 Apr 2024 09:53:49 GMT
• Title: Probing Off-diagonal Eigenstate Thermalization with Tensor Networks
• Authors: Maxine Luo, Rahul Trivedi, Mari Carmen Bañuls, J. Ignacio Cirac,
• Abstract summary: Energy filter methods in combination with quantum simulation can efficiently access the properties of quantum many-body systems. We extend this strategy to explore the properties of off-diagonal matrix elements of observables in the energy eigenbasis. We test the method on integrable and non-integrable spin chains of up to 60 sites, much larger than accessible with exact diagonalization.
• Score: 0.29998889086656577
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Energy filter methods in combination with quantum simulation can efficiently access the properties of quantum many-body systems at finite energy densities [Lu et al. PRX Quantum 2, 020321 (2021)]. Classically simulating this algorithm with tensor networks can be used to investigate the microcanonical properties of large spin chains, as recently shown in [Yang et al. Phys. Rev. B 106, 024307 (2022)]. Here we extend this strategy to explore the properties of off-diagonal matrix elements of observables in the energy eigenbasis, fundamentally connected to the thermalization behavior and the eigenstate thermalization hypothesis. We test the method on integrable and non-integrable spin chains of up to 60 sites, much larger than accessible with exact diagonalization. Our results allow us to explore the scaling of the off-diagonal functions with the size and energy difference, and to establish quantitative differences between integrable and non-integrable cases.

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