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Dynamics of quasiperiodically driven spin systems

Ray, S and Sinha, S and Sen, D (2019) Dynamics of quasiperiodically driven spin systems. In: Physical Review E, 100 (5).

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Official URL: https://doi.org/10.1103/PhysRevE.100.052129


We study the stroboscopic dynamics of a spin-S object subjected to δ-function kicks in the transverse magnetic field which is generated following the Fibonacci sequence. The corresponding classical Hamiltonian map is constructed in the large spin limit, S→∞. On evolving such a map for large kicking strength and time period, the phase space appears to be chaotic; interestingly, however, the geodesic distance increases linearly with the stroboscopic time implying that the Lyapunov exponent is zero. We derive the Sutherland invariant for the underlying SO(3) matrix governing the dynamics of classical spin variables and study the orbits for weak kicking strength. For the quantum dynamics, we observe that although the phase coherence of a state is retained throughout the time evolution, the fluctuations in the mean values of the spin operators exhibit fractality which is also present in the Floquet eigenstates. Interestingly, the presence of an interaction with another spin results in an ergodic dynamics leading to infinite temperature thermalization.

Item Type: Journal Article
Publication: Physical Review E
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Delta functions; Dynamics; Lyapunov methods; Phase space methods; Quantum theory, Fibonacci sequences; Geodesic distances; Lyapunov exponent; Phase coherence; Quantum dynamics; Spin operators; Time evolutions; Transverse magnetic field, Spin fluctuations, article; human; magnetic field; orbit
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited: 11 Oct 2022 11:25
Last Modified: 11 Oct 2022 11:25
URI: https://eprints.iisc.ac.in/id/eprint/77413

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