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arXiv · 2108.12378

Probing infinite many-body quantum systems with finite-size quantum simulators

Viacheslav Kuzmin·Torsten V. Zache·Christian Kokail·Lorenzo Pastori·Alessio Celi·Mikhail Baranov·Peter Zoller
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Abstract

Experimental studies of synthetic quantum matter are necessarily restricted to approximate ground states prepared on finite-size quantum simulators. In general, this limits their reliability for strongly correlated systems, for instance, in the vicinity of a quantum phase transition (QPT). Here, we propose a protocol that makes optimal use of a given finite-size simulator by directly preparing, on its bulk region, a mixed state representing the reduced density operator of the translation-invariant infinite-sized system of interest. This protocol is based on coherent evolution with a local deformation of the system Hamiltonian. For systems of free fermions in one and two spatial dimensions, we illustrate and explain the underlying physics, which consists of quasi-particle transport towards the system's boundaries while retaining the bulk "vacuum". For the example of a non-integrable extended Su-Schrieffer-Heeger model, we demonstrate that our protocol enables a more accurate study of QPTs. In addition, we demonstrate the protocol for an interacting spinful Fermi-Hubbard model with doping for 1D chains and a small two-leg ladder, where the initial state is a random superposition of energetically low-lying states.

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Viacheslav Kuzmin, Torsten V. Zache, Christian Kokail, Lorenzo Pastori, Alessio Celi, Mikhail Baranov, Peter Zoller. 2021-08-27. Probing infinite many-body quantum systems with finite-size quantum simulators. https://doi.org/10.1103/prxquantum.3.020304

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