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相互作用保护周期性驱动的时间晶体免受退相干影响,但会破坏多极驱动下的有序性

Interactions Protect Periodically Driven Time Crystals Against Dephasing but Destabilise Multipolar-Driven Order

Karthikeya Machiraju, Kaustav Bhowmick

arXiv 2609.33574首次发表:更新:

发表机构

PES University(PES大学)

机构由 AI 辅助整理,请以论文原文为准。

AI 中文总结

本研究通过精确对角化比较周期性驱动与多极驱动下的无序 kicked Ising 模型,发现相互作用可保护周期驱动时间晶体免受退相干,但破坏多极驱动有序性,且协调性影响超越总耦合强度。

AI 中文摘要

我们证明,更强的相互作用可以保护周期性驱动的时间晶体有序性免受退相干影响,但在随机多极驱动下会破坏有序性,并且协调性(coordination)的重要性超出了总相互作用强度。我们研究了包含 $N=12$ 和 $16$ 个自旋的无序 kicked Ising 模型,其中包含不完美的 $\pi$ 脉冲和每个位点的退相干,采用精确对角化方法,比较了周期性驱动、阶数 $n=0,1,2$ 的随机多极驱动以及 Thue-Morse 序列,并通过在相等总相互作用强度 $zJ$ 下比较网格(grid)和环(ring)来区分耦合强度与协调性。对于周期性驱动,相干时间近似按 $1/\gamma$ 标度,更强的耦合减少了退相干作用的横向倾斜(transverse tilt)。对于阶数 $n\ge1$ 的多极驱动,在环上加倍耦合将相干时间缩短至 $0.54$($n=1$)、$0.37$($n=2$)和 $0.44$(Thue-Morse)(在 $N=16$ 时),而随机符号($n=0$)不受影响。无序扫描支持一个 toggling-frame 图像,其中相互作用破坏了脉冲误差的块抵消(block cancellation)。在相等 $zJ$ 下,对于周期性驱动,网格的寿命比环长 $2.15$($N=12$)和 $2.78$($N=16$),尽管横向倾斜相同,这是一种超出该图像的协调效应。所有比率在三种相干时间定义下均成立。

英文摘要

We show that stronger interactions protect periodically driven time-crystal order against dephasing but destabilise order under random multipolar drives, and that coordination matters beyond the total interaction strength. We studied a disordered kicked Ising model of $N=12$ and $16$ spins with imperfect $π$ pulses and per-site dephasing by exact diagonalisation, comparing a periodic drive, random multipolar drives of order $n=0,1,2$ and the Thue-Morse sequence, and separated coupling strength from coordination by comparing a grid with a ring at equal total interaction strength $zJ$. For the periodic drive the coherence time scales approximately as $1/γ$, and stronger coupling reduces the transverse tilt on which dephasing acts. For multipolar drives of order $n\ge1$, doubling the coupling on a ring shortens the coherence time to $0.54$ ($n=1$), $0.37$ ($n=2$) and $0.44$ (Thue-Morse) at $N=16$, while random signs ($n=0$) are unaffected. A disorder scan supports a toggling-frame picture in which interactions spoil the block cancellation of the pulse error. At equal $zJ$ the grid outlives the ring by $2.15$ ($N=12$) and $2.78$ ($N=16$) for the periodic drive despite an identical transverse tilt, a coordination effect beyond this picture. All ratios hold under three definitions of the coherence time.

论文原文

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