Adiabatic approximation for three qubits ultrastrongly coupled to a harmonic oscillator

2013/11/30 by Li-Tuo Shen, Rong-Xin Chen, Rongxin Chen +4 · 4 citations
Computer Science · Physics and Astronomy · #Adiabatic process #Charge qubit #Flux qubit #Ground state #Harmonic oscillator #Phase qubit #Physics #Quantum #Quantum Information and Cryptography #Quantum electrodynamics #Quantum entanglement #Quantum harmonic oscillator #Quantum mechanics #Qubit #Spectroscopy and Quantum Chemical Studies #Strong Light-Matter Interactions #Vackář oscillator #Voltage-controlled oscillator #quant-ph

paper · pdf · doi:10.1103/physreva.89.023810

published in Physical Review A 89(2) (American Physical Society) · 12 pages, 9 figures, accepted by Phys. Rev. A

arxiv created 2014/01/29 · openalex publication_date 2014/02/10 · arxiv updated 2014/02/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We study the system involving mutual interaction between three qubits and an oscillator within the ultrastrong coupling regime. We apply the adiabatic approximation approach to explore two extreme regimes: (i) the oscillator's frequency is far larger than each qubit's frequency and (ii) the qubit's frequency is far larger than the oscillator's frequency, and analyze the energy-level spectrum and the ground-state property of the qubit-oscillator system under the conditions of various system parameters. For the energy-level spectrum, we concentrate on studying the degeneracy in low-energy levels. For the ground state, we focus on its nonclassical properties that are necessary for preparing the nonclassical states. We show that the minimum qubit-oscillator coupling strength needed for generating the nonclassical states of the Schr"odinger-cat type in the oscillator is just one half of that in the Rabi model. We find that the qubit-qubit entanglement in the ground state vanishes if the qubit-oscillator coupling strength is strong enough, for which the entropy of three qubits remains larger than 1. We also observe the phase-transition-like behavior in the regime where the qubit's frequency is far larger than the oscillator's frequency.

Citations

• Comparison of quantum and semiclassical radiation theories with application to the beam maser
• Entanglement of Formation of an Arbitrary State of Two Qubits
• A qubit strongly coupled to a resonant cavity: asymmetry of the spontaneous emission spectrum beyond the rotating wave approximation
• Quantum interference structures in trapped-ion dynamics beyond the Lamb-Dicke and rotating wave approximations
• Dissipative dynamics of quantum correlations in the strong-coupling regime
• Manipulating quantum entanglement with atoms and photons in a cavity
• Input-output theory of cavities in the ultrastrong coupling regime: The case of time-independent cavity parameters
• Circuit QED scheme for the realization of the Lipkin-Meshkov-Glick model
• On the Process of Space Quantization
• Qubit-oscillator dynamics in the dispersive regime: Analytical theory beyond the rotating-wave approximation
• Fully connected network of superconducting qubits in a cavity
• Observation of the Bloch-Siegert Shift in a Qubit-Oscillator System in the Ultrastrong Coupling Regime
• Quantum measurement of a coupled nanomechanical resonator–Cooper-pair box system
• Photon Blockade in the Ultrastrong Coupling Regime