Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1310.6127

A Couped-Qubit Tavis Cummings Scheme for Prolonging Quantum Coherence

Amrit De

Published Oct 23, 2013• 0 citations
arXivHTMLPDF

Abstract

Qubit-qubit interactions can significantly boost quantum coherence times for Bell states. The coherence-time-enhancements are however not monotonic and there exists a phase where further increasing the interaction is unhelpful. A resonator in a suggested circuit QED type implementation of the Tavis-Cummings(Dicke) model, is shown to shift this transition point depending on the number of loaded photons. This allows the resonator to amplify the coherence enhancements in certain regimes. The interactions also induce unusual collapse and revival type behavior for the entanglement dynamics. A new and exact open quantum systems formalism -- the quasi-Hamiltonians for the Dicke model thus reveals how a Bell state in a resonator can be protected against $1/f$ noise from randomly fluctuating two level systems. Simple circuit level details are given for flux qubits.

DOI
10.48550/arxiv.1310.6127

Related papers

Coupled-qubit Tavis-Cummings scheme for prolonging quantum coherence

Amrit De

Qubit-qubit interactions can significantly boost quantum coherence times for Bell states. The coherence-time enhancements are, however, not monotonic and there exists a phase where further increasing the interaction is unhelpful. A resonator in a suggested circuit QED-type implementation of the Tavis-Cummings (Dicke) model, is shown to shift this transition point depending on the number of loaded photons. This allows the resonator to amplify the coherence enhancements in certain regimes. The interactions also induce unusual collapse and revival-type behavior for the entanglement dynamics. An exact open quantum system's formalism--(quasi-Hamiltonians for the Dicke model) shows how a Bell state singlet-triplet qubit in a resonator can be protected against $1/f$ noise from randomly fluctuating two-level systems. Simple circuit level details are given for flux qubits.

Physical Review A•Jan 13, 2015•1 citation

Tavis-Cummings model beyond the rotating wave approximation: Quasidegenerate qubits

Shantanu Agarwal, Seyed Mohammad Hashemi Rafsanjani, Joseph H. Eberly

The Tavis-Cummings model for more than one qubit interacting with a common oscillator mode is extended beyond the rotating wave approximation (RWA). We explore the parameter regime in which the frequencies of the qubits are much smaller than the oscillator frequency and the coupling strength is allowed to be ultrastrong. The application of the adiabatic approximation introduced by Irish et al. [Phys. Rev. B 72, 195410 (2005)] for a single-qubit system is extended to the multiqubit case. For a two-qubit system, we identify three-state manifolds of close-lying dressed energy levels and obtain results for the dynamics of intramanifold transitions that are incompatible with results from the familiar regime of the RWA. We exhibit features of two-qubit dynamics that are different from the single-qubit case, including calculations of qubit-qubit entanglement. Both number state and coherent state preparations are considered, and we derive analytical formulas that simplify the interpretation of numerical calculations. Expressions for individual collapse and revival signals of both population and entanglement are derived.

arXiv:1201.2928•Physical Review A•Apr 10, 2012•94 citations

Nonlinearities in the strong coupling regime of the Tavis-Cummings model: from multi-photon resonances to bistability

András Dombi, András Vukics, P. Domokos

In the strong coupling regime of cavity QED where the characteristic damping rates are orders of magnitude below the coherent coupling, resolved multi-photon resonances can be observed for strong enough driving strength. In a certain frequency range, the external coherent drive field hits multi-photon resonances which correspond to very high order transitions that cannot be excited at the given power of the driving field. We found that in this range the cavity field evolves into a robust semiclassical solution which is the mixture of the vacuum and an excited quasi-classical state. The system is reminiscent of optical bistability, however, here a single atom produces a telegraph signal for the outgoing intensity by switching between two states with large photon number difference. We calculate this behavior also for the Tavis-Cummings model representing three qubits in an existing circuit QED experimental setting.

•Apr 30, 2014•0 citations

Magnetization-noise-induced collapse and revival of Rabi oscillations in circuit QED

Amrit De, Robert Joynt

We use a quasi-Hamiltonian formalism to describe the dissipative dynamics of a circuit-QED qubit that is affected by several fluctuating two-level systems with a $1/f$-noise power spectrum. The qubit-resonator interactions are described by the Jaynes-Cummings model. We argue that the presence of pure dephasing noise in such a qubit-resonator system will also induce an energy relaxation mechanism via a fluctuating dipole-coupling term. This random modulation of the coupling is seen to lead to rich physical behavior. For non-Markovian noise, the coupling can either worsen or alleviate decoherence, depending on the initial conditions. The magnetization noise leads to behavior resembling the collapse and revival of Rabi oscillations if the photons are in a coherent state. For a broad distribution of noise couplings, the frequency of these oscillations depends on the mean noise strength. We describe this behavior semianalytically and find it to be independent of the number of fluctuators. This phenomenon could be used as an in situ probe of the noise characteristics.

arXiv:1211.4187•Physical Review A•Apr 29, 2013•8 citations

Influence of initial atomic coherence and direct coupling on qubits entanglement in two-qubit Tavis — Cummings model

A. Othman, A. R. Farhutdinova, Eugene K. Bashkirov

The exact dynamics of a model consisting of two identical qubits interacting non-resonantly with the electromagnetic field mode of an ideal resonator via single-photon transitions is found in the presence of direct Ising interaction of qubits. The exact solution is used to calculate the two-qubit negativity of qubits in the case of a coherent initial state of qubits and a thermal state of the resonator field. It is shown that in the case of resonant interaction of qubits with the field, the initial atomic coherence leads to a significant increase in the maximum degree of entanglement. The inclusion of direct Ising interaction of qubits can significantly enhance the entanglement of qubits in both coherent and non-coherent initial states of qubits. In the case of non-resonant interaction of qubits and the resonator field, the detuning leads to a weakening of the effect of atomic coherence on the dynamics of qubit entanglement.

Vestnik of Samara University Natural Science Series•Jun 19, 2025•0 citations

Persistent asymptotic entangled states in an interacting asymmetric Tavis-Cummings model

Omar Qisieh, Wiam Al-Dress, Gehad Sadiek

The rapid advancement in the field of quantum information processing sparked great interest in developing what are believed to be new promising qubits made of artificial atoms as well as customized natural ones. Those qubits enjoy mutual interaction with other qubits of the same type or different one in what is known as the hybrid quantum systems. In this work, an asymmetrical generalized version of the famous Tavis-Cummings model is used to prototype the behavior of such hybrid systems. The problem is explored in its full generality by analytically solving the model while upholding realistic conditions, namely two mutually interacting non-identical qubits coupled off-resonance to a radiation field, with non-linearity in both the cavity medium and the qubit-field interaction. The work focuses on studying the entanglement dynamics of the system and its asymptotic behavior, with special emphasis on entanglement sudden death (ESD) and birth (ESB). The system is found to exhibit typical death-revival pattern, which asymptotically approaches a pseudo-steady state that is considerably sensitive to the degree of asymmetry between the qubits, the initial state, and other system parameters. We show that for certain initial entangled states, the system parameters can be tuned to provide maximized persistent terminal entanglement values that are steady and free of any collapse-revival patterns or ESD. In contrary, the disentangled initial states asymptotically attain scattered entanglement maxima that lack any systematic behavior. This terminal entanglement behavior can be attained more rapidly by strengthening the mutual interaction between the qubits, a process that is now experimentally accessible with contemporary artificial qubit systems. These results pave the road for preparing strongly entangled qubits in long-life steady states that are crucially needed for performing efficient quantum information algorithms. These systems can be realized using typical qubits such as quantum dots, trapped ions, superconductors, and Rydberg atoms, in either cavity or circuit QED structures.

Optics Express•Apr 14, 2026•0 citations
Qubit-qubit interactions can significantly boost quantum coherence times for Bell states. The coherence-time-enhancements are however not monotonic and there exists a phase where further increasing the interaction is unhelpful. A resonator in a suggested circuit QED type implementation of the Tavis-Cummings(Dicke) model, is shown to shift this transition point depending on the number of loaded photons. This allows the resonator to amplify the coherence enhancements in certain regimes. The interactions also induce unusual collapse and revival type behavior for the entanglement dynamics. A new and exact open quantum systems formalism -- the quasi-Hamiltonians for the Dicke model thus reveals how a Bell state in a resonator can be protected against 1/f1/f1/f noise from randomly fluctuating two level systems. Simple circuit level details are given for flux qubits.
Qubit-qubit interactions can significantly boost quantum coherence times for Bell states. The coherence-time enhancements are, however, not monotonic and there exists a phase where further increasing the interaction is unhelpful. A resonator in a suggested circuit QED-type implementation of the Tavis-Cummings (Dicke) model, is shown to shift this transition point depending on the number of loaded photons. This allows the resonator to amplify the coherence enhancements in certain regimes. The interactions also induce unusual collapse and revival-type behavior for the entanglement dynamics. An exact open quantum system's formalism--(quasi-Hamiltonians for the Dicke model) shows how a Bell state singlet-triplet qubit in a resonator can be protected against 1/f1/f1/f noise from randomly fluctuating two-level systems. Simple circuit level details are given for flux qubits.
The Tavis-Cummings model for more than one qubit interacting with a common oscillator mode is extended beyond the rotating wave approximation (RWA). We explore the parameter regime in which the frequencies of the qubits are much smaller than the oscillator frequency and the coupling strength is allowed to be ultrastrong. The application of the adiabatic approximation introduced by Irish et al. [Phys. Rev. B 72, 195410 (2005)] for a single-qubit system is extended to the multiqubit case. For a two-qubit system, we identify three-state manifolds of close-lying dressed energy levels and obtain results for the dynamics of intramanifold transitions that are incompatible with results from the familiar regime of the RWA. We exhibit features of two-qubit dynamics that are different from the single-qubit case, including calculations of qubit-qubit entanglement. Both number state and coherent state preparations are considered, and we derive analytical formulas that simplify the interpretation of numerical calculations. Expressions for individual collapse and revival signals of both population and entanglement are derived.
In the strong coupling regime of cavity QED where the characteristic damping rates are orders of magnitude below the coherent coupling, resolved multi-photon resonances can be observed for strong enough driving strength. In a certain frequency range, the external coherent drive field hits multi-photon resonances which correspond to very high order transitions that cannot be excited at the given power of the driving field. We found that in this range the cavity field evolves into a robust semiclassical solution which is the mixture of the vacuum and an excited quasi-classical state. The system is reminiscent of optical bistability, however, here a single atom produces a telegraph signal for the outgoing intensity by switching between two states with large photon number difference. We calculate this behavior also for the Tavis-Cummings model representing three qubits in an existing circuit QED experimental setting.
We use a quasi-Hamiltonian formalism to describe the dissipative dynamics of a circuit-QED qubit that is affected by several fluctuating two-level systems with a 1/f1/f1/f-noise power spectrum. The qubit-resonator interactions are described by the Jaynes-Cummings model. We argue that the presence of pure dephasing noise in such a qubit-resonator system will also induce an energy relaxation mechanism via a fluctuating dipole-coupling term. This random modulation of the coupling is seen to lead to rich physical behavior. For non-Markovian noise, the coupling can either worsen or alleviate decoherence, depending on the initial conditions. The magnetization noise leads to behavior resembling the collapse and revival of Rabi oscillations if the photons are in a coherent state. For a broad distribution of noise couplings, the frequency of these oscillations depends on the mean noise strength. We describe this behavior semianalytically and find it to be independent of the number of fluctuators. This phenomenon could be used as an in situ probe of the noise characteristics.
The exact dynamics of a model consisting of two identical qubits interacting non-resonantly with the electromagnetic field mode of an ideal resonator via single-photon transitions is found in the presence of direct Ising interaction of qubits. The exact solution is used to calculate the two-qubit negativity of qubits in the case of a coherent initial state of qubits and a thermal state of the resonator field. It is shown that in the case of resonant interaction of qubits with the field, the initial atomic coherence leads to a significant increase in the maximum degree of entanglement. The inclusion of direct Ising interaction of qubits can significantly enhance the entanglement of qubits in both coherent and non-coherent initial states of qubits. In the case of non-resonant interaction of qubits and the resonator field, the detuning leads to a weakening of the effect of atomic coherence on the dynamics of qubit entanglement.
The rapid advancement in the field of quantum information processing sparked great interest in developing what are believed to be new promising qubits made of artificial atoms as well as customized natural ones. Those qubits enjoy mutual interaction with other qubits of the same type or different one in what is known as the hybrid quantum systems. In this work, an asymmetrical generalized version of the famous Tavis-Cummings model is used to prototype the behavior of such hybrid systems. The problem is explored in its full generality by analytically solving the model while upholding realistic conditions, namely two mutually interacting non-identical qubits coupled off-resonance to a radiation field, with non-linearity in both the cavity medium and the qubit-field interaction. The work focuses on studying the entanglement dynamics of the system and its asymptotic behavior, with special emphasis on entanglement sudden death (ESD) and birth (ESB). The system is found to exhibit typical death-revival pattern, which asymptotically approaches a pseudo-steady state that is considerably sensitive to the degree of asymmetry between the qubits, the initial state, and other system parameters. We show that for certain initial entangled states, the system parameters can be tuned to provide maximized persistent terminal entanglement values that are steady and free of any collapse-revival patterns or ESD. In contrary, the disentangled initial states asymptotically attain scattered entanglement maxima that lack any systematic behavior. This terminal entanglement behavior can be attained more rapidly by strengthening the mutual interaction between the qubits, a process that is now experimentally accessible with contemporary artificial qubit systems. These results pave the road for preparing strongly entangled qubits in long-life steady states that are crucially needed for performing efficient quantum information algorithms. These systems can be realized using typical qubits such as quantum dots, trapped ions, superconductors, and Rydberg atoms, in either cavity or circuit QED structures.