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arXiv · 1007.2857

Dynamics, Synchronization and Quantum Phase Transitions of Two Dissipative Spins

Peter P. Orth·David Roosen·Walter Hofstetter·Karyn Le Hur
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Abstract

We analyze the static and dynamical properties of two Ising-coupled quantum spins embedded in a common bosonic bath as an archetype of dissipative quantum mechanics. First, we elucidate the ground state phase diagram for an ohmic and a subohmic bath using a combination of bosonic numerical renormalization group (NRG), analytical techniques and intuitive arguments. Second, employing the time-dependent NRG we investigate the system's rich dynamical behavior arising from the complex interplay between spin-spin and spin-bath interactions. Interestingly, spin oscillations can synchronize due to the proximity of the common non-Markovian bath and the system displays highly entangled steady states for certain nonequilibrium initial preparations. We complement our non-perturbative numerical results by exact analytical solutions when available and provide quantitative limits on the applicability of the perturbative Bloch-Redfield approach at weak coupling.

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Peter P. Orth, David Roosen, Walter Hofstetter, Karyn Le Hur. 2010-12-01. Dynamics, Synchronization and Quantum Phase Transitions of Two Dissipative Spins. https://doi.org/10.1103/physrevb.82.144423

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