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arXiv · 1910.08101

Quantum many-body scars from virtual entangled pairs

Sambuddha Chattopadhyay·Hannes Pichler·Mikhail D. Lukin·Wen Wei Ho
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Abstract

We study weak ergodicity breaking in a one-dimensional, nonintegrable spin-1 XY model. We construct for it an exact, highly excited eigenstate, which despite its large energy density, can be represented analytically by a finite bond-dimension matrix product state (MPS) with area-law entanglement. Upon a quench to a finite Zeeman field, the state undergoes periodic dynamics with perfect many-body revivals, in stark contrast to other generic initial states which instead rapidly thermalize. This dynamics can be completely understood in terms of the evolution of entangled virtual spin-1/2 degrees of freedom, which in turn underpin the presence of an extensive tower of strong-eigenstate thermalization hypothesis (ETH)-violating many-body eigenstates. The resulting quantum many-body scars are therefore of novel origin. Our results provide important analytical insights into the nature and entanglement structure of quantum many-body scars.

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Sambuddha Chattopadhyay, Hannes Pichler, Mikhail D. Lukin, Wen Wei Ho. 2019-10-17. Quantum many-body scars from virtual entangled pairs. https://doi.org/10.1103/physrevb.101.174308

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