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| Main Authors: | , , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2510.26600 |
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| _version_ | 1866911714897821696 |
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| author | Das, Subhashis Khan, Vishal Rajak, Atanu |
| author_facet | Das, Subhashis Khan, Vishal Rajak, Atanu |
| contents | We characterize various dynamical phases of the simplest version of the quantum kicked top model, a paradigmatic system for studying quantum chaos, which exhibits both regular and chaotic behavior depending on the kick strength. In a previous study, the existence of higher-order discrete time crystals (DTCs) was observed in an infinite-range interacting $p$-spin model, where it was proposed that the order of the DTC satisfies the relation $q\le p$. Within this framework, the $p=2$ model is expected to host only a $2$-DTC phase. However, interestingly, we demonstrate here the existence of a robust $4$-DTC phase in the quantum kicked top, which effectively corresponds to a $p=2$ model with infinite-range interactions. We also show that the system hosts robust $2$-DTC and dynamical freezing (DF) phases around alternating rotationally symmetric points. We explain the emergence of higher-order DTC phases through the classical phase portraits of the system, connected with spin coherent states (SCSs), by identifying special islands that arise within a specific parametric regime. Unlike the $2$-DTC phase, the $4$-DTC phase appears only for certain initial states, as demonstrated through exact calculations. The robustness of the $4$-DTC phase is further investigated through the dynamics of the linear entropy as a function of the angular momentum. We also find an emergent conservation law for both the $2$-DTC and DF phases, while no dynamical conservation arises periodically for the $4$-DTC phase. By investigating the quantum Fisher information, we also demonstrate enhanced metrological sensitivity at the boundaries between different dynamical phases for the estimation of system parameters. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_26600 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Higher-order discrete time crystals and enhanced sensing in a quantum kicked top Das, Subhashis Khan, Vishal Rajak, Atanu Quantum Physics We characterize various dynamical phases of the simplest version of the quantum kicked top model, a paradigmatic system for studying quantum chaos, which exhibits both regular and chaotic behavior depending on the kick strength. In a previous study, the existence of higher-order discrete time crystals (DTCs) was observed in an infinite-range interacting $p$-spin model, where it was proposed that the order of the DTC satisfies the relation $q\le p$. Within this framework, the $p=2$ model is expected to host only a $2$-DTC phase. However, interestingly, we demonstrate here the existence of a robust $4$-DTC phase in the quantum kicked top, which effectively corresponds to a $p=2$ model with infinite-range interactions. We also show that the system hosts robust $2$-DTC and dynamical freezing (DF) phases around alternating rotationally symmetric points. We explain the emergence of higher-order DTC phases through the classical phase portraits of the system, connected with spin coherent states (SCSs), by identifying special islands that arise within a specific parametric regime. Unlike the $2$-DTC phase, the $4$-DTC phase appears only for certain initial states, as demonstrated through exact calculations. The robustness of the $4$-DTC phase is further investigated through the dynamics of the linear entropy as a function of the angular momentum. We also find an emergent conservation law for both the $2$-DTC and DF phases, while no dynamical conservation arises periodically for the $4$-DTC phase. By investigating the quantum Fisher information, we also demonstrate enhanced metrological sensitivity at the boundaries between different dynamical phases for the estimation of system parameters. |
| title | Higher-order discrete time crystals and enhanced sensing in a quantum kicked top |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2510.26600 |