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arXiv · 1212.4709

Mesoscopic mean-field theory for spin-boson chains in quantum optical systems

Pedro Nevado·Diego Porras
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Abstract

We present a theoretical description of a system of many spins strongly coupled to a bosonic chain. We rely on the use of a spin-wave theory describing the Gaussian fluctuations around the mean-field solution, and focus on spin-boson chains arising as a generalization of the Dicke Hamiltonian. Our model is motivated by experimental setups such as trapped ions, or atoms/qubits coupled to cavity arrays. This situation corresponds to the cooperative (E$\otimes$$\beta$) Jahn-Teller distortion studied in solid-state physics. However, the ability to tune the parameters of the model in quantum optical setups opens up a variety of novel intriguing situations. The main focus of this paper is to review the spin-wave theoretical description of this problem as well as to test the validity of mean-field theory. Our main result is that deviations from mean-field effects are determined by the interplay between magnetic order and mesoscopic cooperativity effects, being the latter strongly size-dependent.

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Pedro Nevado, Diego Porras. 2012-12-19. Mesoscopic mean-field theory for spin-boson chains in quantum optical systems. https://doi.org/10.1140/epjst%2Fe2013-01751-1

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