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arXiv · 2305.16964

Anisotropic signatures in the spin-boson model

Felix Hartmann·Stefano Scali·Janet Anders
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Abstract

Thermal equilibrium properties of nanoscale systems deviate from standard macroscopic predictions due to a non-negligible coupling to the environment. For anisotropic three-dimensional materials, we derive the mean force corrections to the equilibrium state of a classical spin vector. The result is valid at arbitrary coupling strength. Specifically, we consider cubic, orthorhombic, and monoclinic symmetries, and compare their spin expectation values as a function of temperature. We underpin the correctness of the mean force state by evidencing its match with the steady state of the simulated non-Markovian spin dynamics. The results show an explicit dependence on the symmetry of the confining material. In addition, some coupling symmetries show a spin alignment transition at zero temperature. Finally, we quantify the work extraction potential of the mean force-generated inhomogeneities in the energy shells. Such inhomogeneities constitute a classical equivalent to quantum coherences.

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BibTeXRIS

Felix Hartmann, Stefano Scali, Janet Anders. 2023-05-26. Anisotropic signatures in the spin-boson model. https://doi.org/10.1103/physrevb.108.184402

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