Browsing by Author "Sen, Arnab"

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    Prominent quantum many-body scars in a truncated Schwinger model
    Desaules, Jean-Yves; Hudomal, Ana; Banerjee, Debasish; Sen, Arnab; Papić, Zlatko; Halimeh, Jad C.
    The high level of control and precision achievable in current synthetic quantum matter setups has enabled first attempts at quantum-simulating various intriguing phenomena in condensed matter physics, including those probing thermalization or its absence in closed quantum systems. In the companion Letter to this article [J.-Y.Desaules et al., Phys. Rev. B 107, L201105 (2023)], we have shown that quantum many-body scars, special low entropy eigenstates that weakly break ergodicity in nonintegrable systems, arise in spin-S quantum link models that converge to (1 + 1)-dimensional lattice quantum electrodynamics (Schwinger model) in the Kogut-Susskindlimit S → ∞. In this work, we further demonstrate that quantum many-body scars exist in a truncated version of the Schwinger model, and are qualitatively more prominent than their counterparts in spin-S quantum link models. We illustrate this by, among other things, performing a finite-S scaling analysis that strongly suggests that scarring persists in the truncated Schwinger model in the limit S → ∞. Although it does not asymptotically converge to the Schwinger model, the truncated formulation is relevant to synthetic quantum matter experiments, and also provides fundamental insight into the nature of quantum many-body scars, their connection to lattice gauge theories, and the thermalization dynamics of the latter. Our conclusions can be readily tested in current cold-atom setups.
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    Weak ergodicity breaking in the Schwinger model
    Desaules, Jean-Yves; Banerjee, Debasish; Hudomal, Ana; Papić, Zlatko; Sen, Arnab; Halimeh, Jad C.
    As a paradigm of weak ergodicity breaking in disorder-free nonintegrable models, quantum many-body scars (QMBS) can offer deep insights into the thermalization dynamics of gauge theories. Having been first discovered in a spin-1/2 quantum link formulation of the Schwinger model, it is a fundamental question as to whether QMBS persist for S>1/2 since such theories converge to the lattice Schwinger model in the large-S limit, which is the appropriate version of lattice QED in one spatial dimension. In this work, we address this question by exploring QMBS in spin-SU(1) quantum link models (QLMs) with staggered fermions. We find that QMBS persist at S>1/2, with the resonant scarring regime, which occurs for a zero-mass quench, arising from simple high-energy gauge-invariant initial product states. We furthermore find evidence of detuned scarring regimes, which occur for finite-mass quenches starting in the physical vacua and the charge-proliferated state. Our results conclusively show that QMBS exist in a wide class of lattice gauge theories in one spatial dimension represented by spin-SQLMs coupled to dynamical fermions, and our findings can be tested on near-term cold-atom quantum simulators of these models.