Variational study of a two-level system coupled to a harmonic oscillator in a ultrastrong coupling regime

Abstract

The nonclassical behaviors of a two-level system coupled to a harmonic oscillator is investigated in the ultrastrong coupling regime. We revisit the variational solution of the ground state and find that the existing solution do not account accurately for nonclassical effects such squeezing. We suggest a new trial wave function and demonstrate that it has an excellent accuracy on the quantum correlation effects as well as on energy.

4 pages; 3 figures; to appear in Phys. Rev. A

References in corpus (4)

• Generalized rotating-wave approximation for arbitrarily large coupling
• Ultrastrong coupling regime of cavity QED with phase-biased flux qubits
• Phonon Squeezing in a Superconducting Molecular Transistor
• Superconducting Qubits Coupled to Torsional Resonators

Cited by in corpus (7)

• Microwave photonics with superconducting quantum circuits
• Deep Strong Coupling Regime of the Jaynes-Cummings model
• Probing the Dynamics of Superradiant Quantum Phase Transition in a Single Trapped-Ion
• Excited-state quantum phase transition in the Rabi model
• Fate of photon blockade in the deep strong coupling regime
• Metastability in the driven-dissipative Rabi model
• The asymmetric quantum Rabi model in the polaron picture