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Dynamics of a large spin with weak dissipation

T. Vorrath·T. Brandes·B. Kramer
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Abstract

We investigate the generalization of the spin-boson model to arbitrary spin size. The Born-Markov approximation is employed to derive a master equation in the regime of small coupling strengths to the environment. For spin one half, the master equation transforms into a set of Bloch equations, the solution of which is in good agreement with results of the spin-boson model for weak ohmic dissipation. For larger spins, we find a superradiance-like behavior known from the Dicke model. The influence of the nonresonant bosons of the dissipative environment can lead to the formation of a beat pattern in the dynamics of the $z$-component of the spin. The beat frequency is approximately proportional to the cutoff $ω_c$ of the spectral function.

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T. Vorrath, T. Brandes, B. Kramer. 2003-12-16. Dynamics of a large spin with weak dissipation. https://doi.org/10.1016/j.chemphys.2003.08.030

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