arXiv subjects

A V Dodonov

Publications and source records attributed to A V Dodonov.

6 recordsLinked to original sources

arXiv2025

Comparison of Quantum and Semiclassical Rabi models near multiphoton resonances in the presence of parametric modulation

We compare the semiclassical and quantum predictions for the unitary dynamics of a two-level atom interacting with a single-mode electromagnetic field in the presence of parametric modulation of the atomic parameters, in the regime of multiphoton atom-field resonances. We derive approximate analytic solutions for the semiclassical Rabi model when the atomic transition frequency and the atom-field coupling strength undergo harmonic external modulations. These solutions are compared to the predictions of the quantum Rabi model, which is solved numerically for the initial coherent state with a large average photon number, of the order of $10^4$, in the regime of three-photon resonance. We show that for initial times and sufficiently intense coherent state the semiclassical dynamics agrees quite well with the quantum one, although for large times it inevitably fails due to the lack of the collapse-revival behavior. Furthermore, we describe how the field state is modified throughout the evolution, presenting numeric results for the average photon number, entropies (related to the atom-field entanglement) and other quantities that characterize the photon number statistics of the electromagnetic field.

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arXiv2022

Generation of photons from vacuum in cavity via time-modulation of a qubit invisible to the field

We propose a scheme for generation of photons from vacuum due to time-modulation of a quantum system coupled indirectly to the cavity field through some ancilla quantum subsystem. We consider the simplest case when the modulation is applied to an artificial 2-level atom (we call t-qubit), while the ancilla is a stationary qubit coupled via the dipole interaction both to the cavity and t-qubit. We find that tripartite entangled states with a small number of photons can be generated from the system ground state under resonant modulations, even when the t-qubit is far detuned from both the ancilla and the cavity, provided its bare and modulation frequencies are properly adjusted as function of other system parameters. We attest our approximate analytic results by numeric simulations and show that photon generation from vacuum persists in the presence of common dissipation mechanisms.

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arXiv2022

Dynamical Casimir effect via modulated Kerr or higher nonlinearities

We show two examples in which the dynamical Casimir effect can be achieved by modulating the Kerr or higher order nonlinearities. In the first case the cavity field is coupled to an arbitrary number of qubits or an harmonic oscillator via the dipole interaction. In the second case, the modulation of the nonlinearities is accompanied by the off-resonance modulation of the cavity frequency. We present the analytic description of the phenomenon and supplement it with numeric simulations, demonstrating that photons can be created from vacuum and the resulting hyper-Poissonian photon statistics is very different from the squeezed vacuum state.

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arXiv2019

Dynamical Casimir effect via four- and five-photon transitions using a strongly detuned atom

The scenario of a single-mode cavity with harmonically modulated frequency is revisited in the presence of strongly detuned qubit or cyclic qutrit. It is found that when the qubit frequency is close to $3ν$ there is a peak in the photon generation rate via four-photon transitions for the modulation frequency $4ν$, where $ν$ is the average cavity frequency. Effective five-photon processes can occur for the modulation frequency $5ν$ in the presence of a cyclic qutrit, and the corresponding transition rates exhibit series of peaks. Closed analytical description is derived for the unitary evolution, and numeric simulations indicate the feasibility of multi-photon dynamical Casimir effect under weak dissipation.

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arXiv2018

1- and 3-photon dynamical Casimir effects using nonstationary cyclic qutrit

We consider the nonstationary circuit QED setup in which a 3-level artificial atom in the $Δ$-configuration interacts with a single-mode cavity field of natural frequency $ω$. It is demonstrated that when some atomic energy level(s) undergoes a weak harmonic modulation, photons can be generated from vacuum via effective 1- and 3-photon transitions, while the atom remains approximately in the ground state. These phenomena occur in the dispersive regime when the modulation frequency is accurately tuned near $ω$ and $3ω$, respectively, and the generated field states exhibit strikingly different statistics from the squeezed vacuum state attained in standard cavity dynamical Casimir effect.

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arXiv2017

Speeding up antidynamical Casimir effect with nonstationary qutrits

The antidynamical Casimir effect (ADCE) is a term coined to designate the coherent annihilation of excitations due to resonant external perturbation of system parameters, allowing for extraction of quantum work from nonvacuum states of some field. Originally proposed for a two-level atom (qubit) coupled to a single cavity mode in the context of nonstationary quantum Rabi model, it suffered from very low transition rate and correspondingly narrow resonance linewidth. In this paper we show analytically and numerically that the ADCE rate can be increased by at least one order of magnitude by replacing the qubit by an artificial three-level atom (qutrit) in a properly chosen configuration. For the cavity thermal state we demonstrate that the dynamics of the average photon number and atomic excitation is completely different from the qubit's case, while the behavior of the total number of excitations is qualitatively similar yet significantly faster.

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