Slow thermalization of exact quantum many-body scar states under perturbations

Lin, Cheng-Ju; Chandran, Anushya; Motrunich, Olexei I.

doi:10.1103/physrevresearch.2.033044

Cited by 67 publications

(48 citation statements)

References 55 publications

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“…Thus, our periodically driven models, including the generalized versions, can be realized in Rydberg atoms. While our model does not require the fine tuning of the parameters, what seems to be difficult is to prepare the initial state in the embedded subspace S. However, considering that the states in the embedded subspace S are equivalent to the Affleck-Kennedy-Lieb-Tasaki state [10] and that the exact scar states can show slow thermalization compared to other states even under local perturbations [43], the observation of the Floquet quantum many-body scars would be physically feasible in the near future. In summary, we have constructed a nonintegrable model which hosts Floquet quantum many-body scars, driven by uniformly imposed Hamiltonians on the constrained Hilbert space prohibiting adjacent pairs of up spins.…”

Section: Discussionmentioning

confidence: 99%

Exact Floquet quantum many-body scars under Rydberg blockade

Mizuta

Takasan

Kawakami

2020

Phys. Rev. Research

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Quantum many-body scars have attracted much interest as a violation of the eigenstate thermalization hypothesis (ETH) due to recent experimental observation in Rydberg atoms and related theoretical studies. In this paper, we construct a model hosting exact Floquet quantum many-body scars, which violate the Floquet version of ETH. We consider two uniformly driven static Hamiltonians prohibiting neighboring up spins (Rydberg blockade) like the PXP model, and construct a binary drive composed of them. We show that there exists a four-dimensional subspace which completely avoids thermalization to infinite temperature and that any other states, including some special scar states reported in the static PXP model, are vulnerable to heating and relax to infinite temperature. We also construct a more generalized periodic drive composed of time-dependent PXP-type Hamiltonians showing exact Floquet quantum many-body scars and discuss possible experimental realization of the model in Rydberg atoms.

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Section: Discussionmentioning

confidence: 99%

Exact Floquet quantum many-body scars under Rydberg blockade

Mizuta

Takasan

Kawakami

2020

Phys. Rev. Research

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“…The experiment is modeled by the "PXP model" [13,14]. While there are several approximate ways of understanding the scar states in the PXP model [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], only some eigenstates in the middle of the spectrum are known exactly [17,21].…”

Section: Introductionmentioning

confidence: 99%

η -pairing states as true scars in an extended Hubbard model

2020

Self Cite

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The η-pairing states are a set of exactly known eigenstates of the Hubbard model on hypercubic lattices, first discovered by Yang [C. N. Yang, Phys. Rev. Lett. 63, 2144 (1989)]. These states are not many-body scar states in the Hubbard model because they occupy unique symmetry sectors defined by the so-called η-pairing SU(2) symmetry. We study an extended Hubbard model with bond-charge interactions, popularized by Hirsch [J. E. Hirsch, Physica C 158, 326 (1989)], where the η-pairing states survive without the η-pairing symmetry and become true scar states. We also discuss similarities between the η-pairing states and exact scar towers in the spin-1 XY model found by Schecter and Iadecola [M. Schecter and T. Iadecola, Phys. Rev. Lett. 123, 147201 (2019)], and systematically arrive at all nearest-neighbor terms that preserve such scar towers in one dimension. We also generalize these terms to arbitrary bipartite lattices. Our study of the spin-1 XY model also leads us to several scarred models, including a spin-1/2 J 1 − J 2 model with Dzyaloshinskii-Moriya interaction, in realistic quantum magnet settings in one and two dimensions.

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“…The scars we construct for λ = 0 are not exact eigenstates for λ = 0. We perform a numerical analysis following a previous study of perturbations in constrained spin chains [54].…”

Section: Robustness To Perturbations and Connection To The Shiraishi-mentioning

confidence: 99%

Weak-ergodicity-breaking via lattice supersymmetry

Surace

Giudici

Dalmonte

2020

Quantum

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We study the spectral properties of D-dimensional N=2 supersymmetric lattice models. We find systematic departures from the eigenstate thermalization hypothesis (ETH) in the form of a degenerate set of ETH-violating supersymmetric (SUSY) doublets, also referred to as many-body scars, that we construct analytically. These states are stable against arbitrary SUSY-preserving perturbations, including inhomogeneous couplings. For the specific case of two-leg ladders, we provide extensive numerical evidence that shows how those states are the only ones violating the ETH, and discuss their robustness to SUSY-violating perturbations. Our work suggests a generic mechanism to stabilize quantum many-body scars in lattice models in arbitrary dimensions.

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Slow thermalization of exact quantum many-body scar states under perturbations

Cited by 67 publications

References 55 publications

Exact Floquet quantum many-body scars under Rydberg blockade

Exact Floquet quantum many-body scars under Rydberg blockade

η -pairing states as true scars in an extended Hubbard model

Weak-ergodicity-breaking via lattice supersymmetry

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