Jaynes-Cummings Model Research Articles

Jaynes-Cummings interaction between low-energy free electrons and cavity photons.

The Jaynes-Cummings Hamiltonian is at the core of cavity quantum electrodynamics; however, it relies on bound-electron emitters fundamentally limited by the binding Coulomb potential. In this work, we propose theoretically a new approach to realizing the Jaynes-Cummings model using low-energy free electrons coupled to dielectric microcavities and exemplify several quantum technologies made possible by this approach. Using quantum recoil, a large detuning inhibits the emission of multiple consecutive photons, effectively transforming the free electron into a few-level system coupled to the cavity mode. We show that this approach can be used for generation of single photons, photon pairs, and even a quantum SWAP gate between a photon and a free electron, with unity efficiency and high fidelity. Tunable by their kinetic energy, quantum free electrons are inherently versatile emitters with an engineerable emission wavelength. Hence, they pave the way toward new possibilities for quantum interconnects between photonic platforms at disparate spectral regimes.

Discrimination of coherent states via atom–field interaction without rotation wave approximation

Quantum state discrimination is an important part of quantum information processing. We investigate the discrimination of coherent states through a Jaynes–Cummings (JC) model interaction between the field and the ancilla without rotation wave approximation (RWA). We show that the minimum failure probability can be reduced as RWA is eliminated from the JC model and the non-RWA terms accompanied by the quantum effects of fields (e.g. the virtual-photon process in the JC model without RWA) can enhance the state discrimination. The JC model without RWA for unambiguous state discrimination is superior to ambiguous state discrimination, particularly when the number of sequential measurements increases. Unambiguous state discrimination implemented via the non-RWA JC model is beneficial to saving resource costs.

Jaynes-Cummings Model in Counter Propagating Waves Basis: Large Numbers of Excitations

Jaynes-Cummings Model in Counter Propagating Waves Basis: Large Numbers of Excitations

Signatures of Dissipation Driven Quantum Phase Transition in Rabi Model.

By using the worldline MonteCarlo technique, matrix product state, and a variational approach àla Feynman, we investigate the equilibrium properties and relaxation features of the dissipative quantum Rabi model, where a two level system is coupled to a linear harmonic oscillator embedded in a viscous fluid. We show that, in the Ohmic regime, a Beretzinski-Kosterlitz-Thouless quantum phase transition occurs by varying the coupling strength between the two level system and the oscillator. This is a nonperturbative result, occurring even for extremely low dissipation magnitude. By using state-of-the-art theoretical methods, we unveil the features of the relaxation towards the thermodynamic equilibrium, pointing out the signatures of quantum phase transition both in the time and frequency domains. We prove that, for low and moderate values of the dissipation, the quantum phase transition occurs in the deep strong coupling regime. We propose to realize this model by coupling a flux qubit and a damped LC oscillator.

Particle-Hole Ansatz in the Jaynes-Cummings-Hubbard Model

A recurrence relation ansatz between annihilation operators applied to the hopping interaction term of the Jaynes-Cummings-Hubbard model (JCHM) reduces the JCHM to that of the ordinary Jaynes-Cummings model (JCM), albeit, with a boson energy depending on the hopping strength. This allows us to calculate the phase diagram for the Mott-to-superfluid phase transition and the critical hopping strength as a function of the detuning.

Nodes and Spin Windings for Topological Transitions in Light–Matter Interactions

AbstractThe anisotropic quantum Rabi model (QRM) is the fundamental model of light–matter interactions with indispensable counter‐rotating terms in ultra‐strong couplings. By extracting different levels of topological information a new light is shed on the energy spectrum of the anisotropic QRM. Besides conventional topological transitions (TTs) at gap closing, abundant unconventional TTs are unveiled underlying level anticrossings without gap closing by tracking the wave‐function nodes, including a particular unconventional TT which turns out to be universal for different energy levels. On the other hand, it is found that the nodes have a correspondence to spin windings, which not only endows the nodes a more explicit topological character in supporting single‐qubit TTs but also turns the topological information physically detectable. Furthermore, hidden small‐spin‐knot transitions are exposed for the ground state, while more kinds of spin‐knot transitions emerge in excited states including unmatched node numbers and spin winding numbers. Based on node sorting, algebraic formulation is established to decode the topological information encoded geometrically in the wave functions and spin windings.

Supersymmetry as an Algebraic Approach to the Jaynes-Cumming Model with Stark Shift and Kerr-Like Medium

Supersymmetry as an Algebraic Approach to the Jaynes-Cumming Model with Stark Shift and Kerr-Like Medium

Multiple-photon bundle emission in the n-photon Jaynes-Cummings model.

We study the multiple-photon bundle emission in the n-photon Jaynes-Cummings model composed of a two-level system coupled to a single-mode optical field via the n-photon exciting process. Here, the two-level system is strongly driven by a near-resonant monochromatic field, and hence the system can work in the Mollow regime, in which a super-Rabi oscillation between the zero-photon state and the n-photon state can take place under proper resonant conditions. We calculate the photon number populations and the standard equal-time high-order correlation functions, and find that the multiple-photon bundle emission can occur in this system. The multiple-photon bundle emission is also confirmed by investigating the quantum trajectories of the state populations and both the standard and generalized time-delay second-order correlation functions for multiple-photon bundle. Our work paves the way towards the study of multiple-photon quantum coherent devices, with potential application in quantum information sciences and technologies.

Cavity transmission in a QD-cavity system using Cluster Expansion: Beyond the mean-field approach

We theoretically study the temporal evolution of the mean number of photons in a strongly coupled cavity quantum dot system driven by a symmetric laser pulse using the Cluster Expansion method. The quantum dot is modeled as a two-level system that interacts with a single mode of the quantized electromagnetic field according to the Jaynes–Cummings model. We compare our results with those obtained through the Master Equation method and find that second-order Cluster Expansion is sufficient to reproduce the transmission spectrum without losing the fundamental physical processes and with a relatively low computational cost.

The interplay of symmetry with the Rabi oscillation in the non-Hermitian double Jaynes–Cummings model

We study the dynamical evolution and symmetry breaking of the non-Hermitian double Jaynes–Cummings model with symmetry. The results indicate that there exist symmetry maintained and breaking phase in this model, and the non-Hermitian terms lead to different behaviors in two phases. In the symmetry phase, there exists stable Rabi oscillation caused by the interaction between photons and atoms. At the exceptional point, the system shows critical property that the probabilities in each state over time tend to be equal. The system will undergo a transition from the symmetry phase to the symmetry breaking phase, as increasing the coupling constant. In the symmetry breaking phase, complex eigenvalues appear, and the probability in each state increases monotonically in an exponential form. This study can help us to understand the effect of symmetry on the interaction between photons and atoms in non-Hermitian systems.

Criticality-enhanced quantum sensing in the anisotropic quantum Rabi model

Quantum systems that undergo quantum phase transitions exhibit divergent susceptibility and can be exploited as probes to estimate physical parameters. We generalize the dynamic framework for criticality-enhanced quantum sensing by the quantum Rabi model (QRM) to its anisotropic counterpart and derive the correspondingly analytical expressions for the quantum Fisher information (QFI). We find that the contributions of the rotating-wave and counterrotating-wave interaction terms are symmetric at the limit of the infinite ratio of qubit frequency to field frequency, with the QFI reaching a maximum for the isotropic QRM. At finite frequency scaling, we analytically derive the inverted variance of higher-order correction and find that it is more affected by the rotating-wave coupling than by the counterrotating-wave coupling.

Quantum switching between nonclassical correlated single photons and two-photon bundles in a two-photon Jaynes-Cummings model.

We propose a scheme to realize a two-photon Jaynes-Cummings model for a single atom inside an optical cavity. It is shown that the interplay of a laser detuning and atom (cavity) pump (driven) field gives rise to the strong single photon blockade, two-photon bundles, and photon-induced tunneling. With the cavity driven field, strong photon blockade occurs in the weak coupling regime, and switching between single photon blockade and photon-induced tunneling at two-photon resonance are achievable via increasing the driven strength. By turning on the atom pump field, quantum switching between two-photon bundles and photon-induced tunneling at four-photon resonance are realized. More interestingly, the high-quality quantum switching between single photon blockade, two-photon bundles, and photon-induced tunneling at three-photon resonance is achieved with combining the atom pump and cavity driven fields simultaneously. In contrast to the standard two-level Jaynes-Cummings model, our scheme with generating a two-photon (multi-photon) Jaynes-Cummings model reveals a prominent strategy to engineer a series of special nonclassical quantum states, which may pave the way for investigating basic quantum devices to implement in quantum information processing and quantum networks.

Quantum speed limit of Jaynes-Cummings model with detuning for arbitrary initial states

The quantum speed limit (QSL) of the Jaynes-Cummings model with detuning for arbitrary initial states is investigated. We mainly focus on the influences of the detuning, width of Lorentzian spectral density, and coherence of the initial state on the non-Markovian speedup evolution in an open system. It is found that even in the Markovian regime, increasing the detuning parameter leads to quantum speedup. Moreover, we reveal that the QSL has an inverse relation with the population of the initial excited state. Notably, we show that the QSL depends on the quantum coherence of the system's initial state such that the maximal coherent state can saturate its bound.

QUANTUM TELEPORTATION OF ENTANGLED STATES VIA GENERALIZED PHOTON-ADDED PAIR COHERENT STATE

In this paper, we study the quantum teleportation of an unknown atomic state based on the two-photon Jaynes-Cummings model, consisting of an effective two-level atom with a two-mode field in the generalized photon-added pair coherent state (GPAPCS). By applying the detecting method, we use a scheme that includes two two-level atoms and a cavity field to teleport the unknown atomic state from a sender to a receiver. The results show that the number of photons added to the field and the intensity of the initial field influence the average fidelity and success probability of the teleportation process. The time-evolution dependence of the average fidelity is also considered and compared for the field in the pair coherent state and in the GPAPCS.

Observation of topological pumping of a defect state in a Fock photonic lattice

Topological pumping connects the topological features of a modulated system with its transport behavior. It provides a powerful means for robust topological transport between distant nodes even in a one-dimensional chain, which may find applications in wave manipulation and quantum information processing. Here, we experimentally demonstrate an adiabatic pumping scheme, topological pumping of a defect state, by introducing a Fock photonic lattice, which is a classical analog of the Fock-state lattice of the two-mode Jaynes-Cummings model. Since this pumping is always protected by an energy gap even for a large-size system, its pumping efficiency can be enhanced considerably compared with the conventional topological pumping schemes. Moreover, a topologically protected beam splitter is also realized by designing the pumping channels of a defect state. The experimental results agree well with theoretical simulations. Our scheme provides a different route to study topological transport and implement novel photonic devices.

Dynamics of quantum coherence in the Jaynes–Cummings model with quenched disorder

We have applied the quantum coherence theory to the Jaynes–Cummings model for three types of quenched disorder distribution: uniform, Gaussian, and Cauchy-Lorentz. Under certain conditions, we have observed a beat-damping behavior on the dynamics of the l1-norm of coherence. This phenomenon is more evident for the uniform disorder distribution.

A study of the effective Hamiltonian method for decay dynamics* *Project supported by the National Natural Science Foundation of China (11964010, 11564013 and 11464014), the Natural Science Foundation of Hunan Province (2020JJ4495), the Scientific Research Fund of Hunan Provincial Education Department (22A0377 and 21A0333), and the Jishou University Innovation Foundation for Postgraduate (Jdy20038).

The decay dynamic of an excited quantum emitter (QE) is one of the most important contents in quantum optics. It has been widely applied in the field of quantum computing and quantum state manipulation. When the electromagnetic environment is described by several pseudomodes, the effective Hamiltonian method based on the multi-mode Jaynes–Cummings model provides a clear physical picture and a simple and convenient way to solve the decay dynamics. However, in previous studies, only the resonant modes are taken into account, while the non-resonant contributions are ignored. In this work, we study the applicability and accuracy of the effective Hamiltonian method for the decay dynamics. We consider different coupling strengths between a two-level QE and a gold nanosphere. The results for dynamics by the resolvent operator technique are used as a reference. Numerical results show that the effective Hamiltonian method provides accurate results when the two-level QE is resonant with the plasmon. However, when the detuning is large, the effective Hamiltonian method is not accurate. In addition, the effective Hamiltonian method cannot be applied when there is a bound state between the QE and the plasmon. These results are of great significance to the study of the decay dynamics in micro-nano structures described by quasi-normal modes.

Lossy Micromaser Battery: Almost Pure States in the Jaynes-Cummings Regime.

We consider a micromaser model of a quantum battery, where the battery is a single mode of the electromagnetic field in a cavity, charged via repeated interactions with a stream of qubits, all prepared in the same non-equilibrium state, either incoherent or coherent, with the matter-field interaction modeled by the Jaynes-Cummings model. We show that the coherent protocol is superior to the incoherent one, in that an effective pure steady state is achieved for generic values of the model parameters. Finally, we supplement the above collision model with cavity losses, described by a Lindblad master equation. We show that battery performances, in terms of stored energy, charging power, and steady-state purity, are slightly degraded up to moderated dissipation rate. Our results show that micromasers are robust and reliable quantum batteries, thus making them a promising model for experimental implementations.

Quantum Rabi dynamics of trapped atoms far in the deep strong coupling regime

The coupling of a two-level system with an electromagnetic field, whose fully quantized version is the quantum Rabi model, is among the central topics of quantum physics. When the coupling strength becomes large enough that the field mode frequency is reached, the deep strong coupling regime is approached, and excitations can be created from the vacuum. Here we demonstrate a periodic variant of the quantum Rabi model in which the two-level system is encoded in the Bloch band structure of cold rubidium atoms in optical potentials. With this method we achieve a Rabi coupling strength of 6.5 times the field mode frequency, which is far in the deep strong coupling regime, and observe a subcycle timescale raise in bosonic field mode excitations. In a measurement recorded in the basis of the coupling term of the quantum Rabi Hamiltonian, a freezing of dynamics is revealed for small frequency splittings of the two-level system, as expected when the coupling term dominates over all other energy scales, and a revival for larger splittings. Our work demonstrates a route to realize quantum-engineering applications in yet unexplored parameter regimes.

First-order quantum phase transition and entanglement in the Jaynes–Cummings model with a squeezed light

We study the quantum phase transition and entanglement in the Jaynes–Cummings model with squeezed light, utilize a special transformation method to obtain the analytical ground state of the model within the near-resonance regime, and numerically verify the validity of the analytical ground state. It is found that the ground state exhibits a first-order quantum phase transition at the critical point linearly induced by squeezed light, and the ground state entanglement reaches its maximum when the qubit-field coupling strength is large enough at the critical point.