An analytical variational method for the biased quantum Rabi model in the ultra-strong coupling regime

Abstract

An analytical variational method for the ground state of the biased quantum Rabi model in the ultra-strong coupling regime is presented. This analytical variational method can be obtained by a unitary transformation or alternatively by assuming the form of ground state wave function. The key point of the method is to introduce a variational parameter $\lambda$, which can be determined by minimizing the energy functional. Using this method, we calculate physical observables with high accuracy in comparison with the numerical exact one. Our method evidently improves the results from the widely used general rotating-wave approximation (GRWA) in both qualitative and quantitative ways.

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Cited by in corpus (5)

• Hidden symmetry and tunnelling dynamics in asymmetric quantum Rabi models
• Attempt to find the hidden symmetry in the asymmetric quantum Rabi model
• Generalized adiabatic approximation to the asymmetric quantum Rabi model: conical intersections and geometric phases
• Non-orthogonal qubit states expansion for the asymmetric quantum Rabi model
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