Cavity Quantum Electrodynamics Model Research Articles

Non-Hermitian cavity quantum electrodynamics-configuration interaction singles approach for polaritonic structure with ab initio molecular Hamiltonians.

We combine ab initio molecular electronic Hamiltonians with a cavity quantum electrodynamics model for dissipative photonic modes and apply mean-field theories to the ground- and excited-states of resulting polaritonic systems. In particular, we develop a non-Hermitian configuration interaction singles theory for mean-field ground- and excited-states of the molecular system strongly interacting with a photonic mode and apply these methods to elucidating the phenomenology of paradigmatic polaritonic systems. We leverage the Psi4Numpy framework to yield open-source and accessible reference implementations of these methods.

Probing the spectrum of the Jaynes-Cummings-Rabi model by its isomorphism to an atom inside a parametric amplifier cavity

We show how the Jaynes--Cummings--Rabi model of cavity quantum electrodynamics can be realized via an isomorphism to the Hamiltonian of a qubit inside a parametric amplifier cavity. This realization clears the way to observe the full spectrum of the Rabi model via a probe applied to a parametric amplifier cavity containing a qubit and a parametric oscillator operating below threshold. An important outcome of the isomorphism is that the actual frequencies are replaced by detunings which make it feasible to reach the ultra-strong coupling regime. We find that inside this regime the probed spectrum displays a narrow resonance peak that is traced back to the transition between ground and first excited states. The exact form of these states is given at an energy crossing and then extended numerically. At the crossing, the eigenstates are entangled states of field and atom where the field is found inside squeezed cat states.

Time-resolved vacuum Rabi oscillations in a quantum-dot–nanocavity system

We report time-domain observation of vacuum Rabi oscillations in a single quantum dot strongly coupled to a nanocavity under incoherent optical carrier injection. We realize a photonic crystal nanocavity with a very high quality factor of >80,000 and employ it to clearly resolve the ultrafast vacuum Rabi oscillations by simple photoluminescence-based experiments. We found that the time-domain vacuum Rabi oscillations were largely modified when changing the pump wavelength and intensity, even when marginal changes were detected in the corresponding photoluminescence spectra. We analyze the measured time-domain oscillations by fitting to simulation curves obtained with a cavity quantum electrodynamics model. The observed modifications of the oscillation curves were mainly induced by the change in the carrier capture and dephasing dynamics in the quantum dot, as well as the change in bare-cavity emission. This result suggests that vacuum Rabi oscillations can be utilized as a highly sensitive probe for the quantum dot dynamics. Our work points out a powerful alternative to conventional spectral-domain measurements for a deeper understanding of the vacuum Rabi dynamics in quantum dot-based cavity quantum electrodynamics systems.

Photon statistics on the extreme entanglement.

The effects of photon bunching and antibunching correspond to the classical and quantum features of the electromagnetic field, respectively. No direct evidence suggests whether these effects can be potentially related to quantum entanglement. Here we design a cavity quantum electrodynamics model with two atoms trapped in to demonstrate the connections between the steady-state photon statistics and the two-atom entanglement. It is found that within the weak dissipations and to some good approximation, the local maximal two-atom entanglements perfectly correspond to not only the quantum feature of the electromagnetic field—the optimal photon antibunching, but also the classical feature—the optimal photon bunching. We also analyze the influence of strong dissipations and pure dephasing. An intuitive physical understanding is also given finally.

Optical nonlinearity in a quantum dot–microcavity system under an external magnetic field

We theoretically study the dynamics of a strongly coupled quantum dot–bimodal microcavity system under an external magnetic field, where the nondegenerate excitonic spin states caused by the Zeeman effect are coupled to both orthogonal cavity modes. We develop an effective cavity quantum electrodynamics model, demonstrate the polarization-related nonlinear response under a linearly polarized pulse excitation by calculating the time-resolved intracavity photon number, and investigate the dependence of system parameters on the nonlinearity. In addition, we show that, when driven by two pulses with perpendicular polarization and a relative time delay, the coupled system suppresses the delayed one, which can be applied to polarized optical switching at a single-photon level.

Unitary decoupling treatment of a quadratic bimodal cavity quantum electrodynamics model

We consider a two-photon quantum model of radiation–matter interaction between a single two-level atom and a degenerate bimodal high-Q cavity field. Within this tripartite system, the explicit construction of two collective radiation modes, one of which is freely evolving and the other one quadratically coupled to the matter subsystem, is reported. The meaning and advantages of such a decoupling treatment are carefully discussed.

Drude Weight, Cyclotron Resonance, and the Dicke Model of Graphene Cavity QED

The unique optoelectronic properties of graphene make this two-dimensional material an ideal platform for fundamental studies of cavity quantum electrodynamics in the strong-coupling regime. The celebrated Dicke model of cavity quantum electrodynamics can be approximately realized in this material when the cyclotron transition of its 2D massless Dirac fermion carriers is nearly resonant with a cavity photon mode. We develop the theory of strong matter-photon coupling in this circumstance, emphasizing the essential role of a dynamically generated matter energy term that is quadratic in the photon field and absent in graphene's low-energy Dirac model.

Vacuum-Induced Abelian and Non-Abelian Gauge Potentials in Cavity Quantum Electrodynamics

Gauge potential plays an important role in exploring exotic phenomena in the single- and many-body quantum systems. In this paper, we propose a scheme to create both new Abelian and non-Abelian gauge potentials by adiabatically controlling the degenerate Dicke model in cavity quantum electrodynamics. It is shown that a non-Abelian gauge potential is achieved only for a single atom, whereas an Abelianizen diagonal gauge potential is realized for the atomic ensemble. More importantly, two interesting quantum phenomena such as the geometric phase and the magnetic monopole induced by our created gauge potentials are also predicted. The possible physical realization is presented in the macroscopic circuit quantum electrodynamics with the Cooper pair boxes, which act as the artificial two-level atoms controlled by the gate voltage and the external magnetic flux.

Solid state multi-ensemble quantum computer in cavity quantum electrodynamics model

The first realization of solid state quantum computer was demonstrated recently by using artificial atoms — transmons in superconducting resonator. Here, we propose a novel quantum computer based on quantum electrodynamic cavity coupling many quantum nodes of controlled atomic ensembles. The quantum computer contains quantum memory and processing nodes. For the first time, we find the optimal practically attainable parameters of the atoms and optical scheme of the computer for realization of the multimode quantum memory for the photonic qubits with efficiency close to 100%. Then we reveal self modes for reversible transfer of the qubits between the quantum memory node and the processing nodes. Also, we find a realization of iSWAP gate via direct coupling of two processing nodes with an operation rate accelerated proportionally to the number of atoms in the nodes. Collective dynamic and static blockade mechanisms are proposed for realization of $\sqrt {iSWAP} $ quantum gate in multi atomic ensembles. A large number of the two-qubit gates can be simultaneously realized that opens a possibility for parallel quantum processing in the proposed quantum computer.

Entanglement, fidelity, and quantum-classical correlations with an atom moving in a quantized cavity field

Stability and instability of quantum evolution are studied in the interaction between a two-level atom with photon recoil and a quantized field mode in an ideal cavity, the basic model of cavity quantum electrodynamics (QED). It is shown that the Jaynes-Cummings dynamics can be unstable in the regime of chaotic walking of the atomic center-of-mass in the quantized field of a standing wave in the absence of any kind of interaction with environment. This kind of quantum instability manifests itself in strong variations of reduced quantum purity and entropy, correlating with the respective classical Lyapunov exponent, and in exponential sensitivity of fidelity of quantum states to small variations in the atom-field detuning. The connection between quantum entanglement and fidelity and the center-of-mass motion is clarified analytically and numerically for a few regimes of that motion. The results are illustrated with two specific initial field states: the Fock and coherent ones. Numerical experiments demonstrate various manifestations of the quantum-classical correspondence, including dynamical chaos and fractals, which can be, in principle, observed in real experiments with atoms and photons in high finesse cavities.

Atomic fractals in cavity quantum electrodynamics

Fractal-like structures are found in the basic model in cavity quantum electrodynamics describing nonlinear motion of a two-level atom with recoil strongly coupled to a single-mode quantized field in a standing-wave microcavity.

The standard model in cavity quantum electrodynamics. II. Coupling constants and atom field integration

The standard model in cavity quantum electrodynamics. II. Coupling constants and atom field integration

The standard model in cavity quantum electrodynamics. II. Coupling constants and atom field interaction

The standard model in cavity quantum electrodynamics. II. Coupling constants and atom field interaction

The standard model in cavity quantum electrodynamics. I. General features of mode functions for a Fabry-Perot cavity

The standard model in cavity quantum electrodynamics. I. General features of mode functions for a Fabry-Perot cavity

The standard model in cavity quantum electrodynamics. II. Coupling constants and atom field interaction

Specific forms of the travelling and trapped vector mode functions for a three-dimensional Fabry-Perot cavity are developed from the general results of the preceding paper, with parameters describing the output cavity mirror chosen for a typical high Q cavity case. Cavity and external quasi-mode functions associated with the quasi-mode theory of macroscopic canonical quantization are then obtained via an idealized choice of output mirror parameters. The coupling constants describing photon exchange processes between the single cavity quasi-mode associated with each Fabry-Perot resonance and various external quasi-modes are calculated, and their slow dependence on the external quasi-mode frequency shows that the conditions for irreversible Markovian damping of the cavity quasi-mode are satisfied. For radiative atoms placed in the cavity the coupling constants for energy exchange processes with sideways travelling external quasi-modes also vary slowely, so that Markovian spontaneous emission damping occurs for the radiative atoms. However, their coupling with the isolated cavity quasi-modes is associated with reversible photon exchanges as represented via one photon Rabi frequencies. The standard model in cavity quantum electrodynamics, in which the basic processes are described by a cavity damping rate, a radiative atom spontaneous decay rate and an atom-cavity mode coupling constant has now been justified in terms of the quasi-mode theory of macroscopic canonical quantization.

The standard model in cavity quantum electrodynamics. I. General features of mode functions for a Fabry-Perot cavity

In the present and the accompanying paper a justification of the standard model of cavity quantum electrodynamics is given in terms of a quasi-mode theory of macroscopic canonical quantization. The coupling of the cavity quasi-mode to external quasi-modes is treated for the representative case of the three-dimensional Fabry-Perot cavity. The general form of the travelling and trapped mode functions for this cavity are derived in this paper and the mode-mode coupling constants are calculated in the accompanying paper. The slow dependence of the coupling constants with the mode frequency difference demonstrates that the conditions for Markovian damping of the cavity quasimode are satisfied. As also discussed in the accompanying paper, the interaction of radiative atoms with cavity quasi-modes is associated with reversible energy exchanges between atom and cavity and represented by Rabi coupling constants. The interaction of radiative atoms located within the cavity with sideways travelling external quasi-modes involves slowly varying coupling constants and is associated with irreversible spontaneous emission dampling. The basic processes represented in the standard cavity quantum electrodynamics model and the associated coupling constant and decay rates thereby follow from the quasi-mode theory.

CAVITY QUANTUM ELECTRODYNAMICS OF COMPETING ONE AND TWO PHOTON PROCESSES

We consider a new model of cavity quantum electrodynamics consisting of the interaction of a single mode of electromagnetic field with two non-identical two-level atoms undergoing one and two photon transition respectively in an ideal cavity. The exact analytic results for the vacuum Rabi splitting and the dynamical evolution of the model are given.