Quantum dynamics of a spin model with an extensive degeneracy

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Hauptverfasser: Ghosh, Krishanu, Sen, Diptiman, Sengupta, K.
Format: Preprint
Veröffentlicht: 2025
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author Ghosh, Krishanu
Sen, Diptiman
Sengupta, K.
author_facet Ghosh, Krishanu
Sen, Diptiman
Sengupta, K.
contents We study the role played by extensive degeneracy in shaping the nature of the quantum dynamics of a one-dimensional spin model for both ramp and periodic drive protocols. The model displays an extensive degenerate manifold of states for a specific value of one of the parameters of its Hamiltonian. We study a linear ramp which takes the spin model through this degenerate point and show that it leads to a deviation from the usual Kibble-Zurek behavior. We also study the Stückelberg oscillations in such a model for a ramp which passes twice through the degenerate point. Our study indicates that such oscillations are strongly suppressed leading to a distinct behavior compared to those arising from double passage through a quantum critical point. Finally, we study the periodic dynamics of the model and show, for a large drive amplitude, the existence of special drive frequencies at which the system exhibits an approximate emergent $U(1)$ symmetry. We study the effect of this emergent symmetry on the correlators of the driven system and demonstrate the existence of dynamic symmetry restoration at these frequencies. We study the fate of the emergent symmetry when the drive amplitude is decreased and discuss possible experiments to test our theory.
format Preprint
id arxiv_https___arxiv_org_abs_2502_07609
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantum dynamics of a spin model with an extensive degeneracy
Ghosh, Krishanu
Sen, Diptiman
Sengupta, K.
Quantum Physics
Strongly Correlated Electrons
We study the role played by extensive degeneracy in shaping the nature of the quantum dynamics of a one-dimensional spin model for both ramp and periodic drive protocols. The model displays an extensive degenerate manifold of states for a specific value of one of the parameters of its Hamiltonian. We study a linear ramp which takes the spin model through this degenerate point and show that it leads to a deviation from the usual Kibble-Zurek behavior. We also study the Stückelberg oscillations in such a model for a ramp which passes twice through the degenerate point. Our study indicates that such oscillations are strongly suppressed leading to a distinct behavior compared to those arising from double passage through a quantum critical point. Finally, we study the periodic dynamics of the model and show, for a large drive amplitude, the existence of special drive frequencies at which the system exhibits an approximate emergent $U(1)$ symmetry. We study the effect of this emergent symmetry on the correlators of the driven system and demonstrate the existence of dynamic symmetry restoration at these frequencies. We study the fate of the emergent symmetry when the drive amplitude is decreased and discuss possible experiments to test our theory.
title Quantum dynamics of a spin model with an extensive degeneracy
topic Quantum Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2502.07609