Quantum Features of the Thermal Two-Qubit Quantum Rabi Model in Ultra- and Deep-Strong Regimes
arXiv:2503.23654 · doi:10.1002/qute.202500250
Abstract
Quantum correlations and non-classical states are indispensable resources for advancing quantum technologies, and their resilience at finite temperatures is crucial for practical experimental implementations. The two-qubit quantum Rabi model (2QQRM), a natural extension of the quantum Rabi model, describes two qubits coupled to a single bosonic mode and has been extensively studied in cavity quantum electrodynamics, superconducting circuits, and quantum information science. In this work, we investigate the persistence of quantum correlations and non-classical states in the 2QQRM at thermal equilibrium, focusing on the ultrastrong and deep strong coupling regimes. Through a systematic analysis of quantumness quantifiers, we demonstrate the emergence of long-lived quantum correlations, even in the presence of thermal noise. Notably, we uncover striking phenomena arising from the interplay between detuning and deep strong-coupling: in the high-frequency limit, where the qubit energy exceeds the cavity-mode energy, quantum criticality emerges, leading to a high degree of photon squeezing. In contrast, the opposite regime is characterized by robust qubit-qubit quantum correlations. Importantly, we show that both dispersive regimes exhibit quantum features that are remarkably robust to parameter fluctuations, making them advantageous for maintaining quantum coherence. These results highlight the exceptional resilience of quantum resources in the 2QQRM and provide valuable insights for developing quantum technologies operating under realistic, finite-temperature conditions.
References in corpus (28)
- QuTiP 2: A Python framework for the dynamics of open quantum systems
- Beyond the Jaynes-Cummings model: circuit QED in the ultrastrong coupling regime
- Microwave photonics with superconducting quantum circuits
- Demonstration of Two-Qubit Algorithms with a Superconducting Quantum Processor
- Coherent quantum state storage and transfer between two phase qubits via a resonant cavity
- Dressed Collective Qubit States and the Tavis-Cummings Model in Circuit QED
- Some remarks on 'superradiant' phase transitions in light-matter systems
- Nonclassical Radiation from Thermal Cavities in the Ultrastrong Coupling Regime
- Excited-state quantum phase transition in the Rabi model
- Quantum metrology with boundary time crystals
- Role of quantum correlations in light-matter quantum heat engines
- Non-equilibrium many-body effects in driven nonlinear resonator arrays
- Nonadiabatic coherent evolution of two-level systems under spontaneous decay
- Symmetrized Liouvillian Gap in Markovian Open Quantum Systems
- Generalized rotating-wave approximation to the two-qubit and cavity coupling system
- Quantum Rabi dynamics of trapped atoms far in the deep strong coupling regime
- Decoherence Free Subspace and entanglement by interaction with a common squeezed bath
- One-photon Solutions to Multiqubit Multimode quantum Rabi model
- Probing of nonlinear hybrid optomechanical systems via partial accessibility
- Concise analytic solutions to the quantum Rabi model with two arbitrary qubits
- Detecting virtual photons in ultrastrongly coupled superconducting quantum circuits
- Steady entanglements in bosonic dissipative networks
- Steady many-body entanglements in dissipative systems
- Thermodynamic Limit in the Two-qubit Quantum Rabi Model with Spin-Spin Coupling
- Implication of giant photon bunching on quantum phase transition in the dissipative anisotropic quantum Rabi model
- Quantum thermalization and thermal entanglement in the open quantum Rabi model
- Deterministic single-photon source in the ultrastrong coupling regime
- Tripartite quantum Rabi model with trapped Rydberg ions