Mode Of Electromagnetic Field Research Articles

Application of the Jacobi functional equation and the ATS theorem in a quantum optical model

A new method is devised to study the atomic inversion in the model of a two-level atom interacting with a single quantized mode of the (initially coherent) electromagnetic field in an ideal resonant cavity. The method is based on number-theoretic results applied to the approximation of special series, specifically, on the functional equation for Jacobi theta functions and the ATS theorem. New asymptotic formulas are derived, with the help of which the behavior of the atomic inversion function on various time intervals can be determined in detail depending on the parameters of the system.

Strong Light–Matter Interaction in Quantum Emitter/Metal Hybrid Nanostructures

Surface plasmon polaritons (SPPs) are spatially confined electromagnetic field modes at a metal-dielectric interface capable of generating intense near-field optical forces on ultrafast time scales. Within the field of photonics, SPPs carry significant potential for guiding and manipulating light on the nanoscale. The intense SPP fields substantially enhance light–matter interactions with quantum emitters (QEs). Thus, hybrid systems comprised of SPP resonators and various types of QEs constitute key components of the modern photonics applications. Recent advances in nanotechnology have enabled fabrication of high quality QE/metal hybrid nanostructures, in which several aspects of light–matter interactions, including those in the quantum regime have been demonstrated and extensively studied. The present Perspective explores the central phenomenon in light–matter interaction in emitter/metal hybrid nanostructures, namely, the strong dipole coupling between QEs and SPPs, particularly between excitons (Xs) an...

Entanglement of Two Two-Level Atoms and Two Modes of Electromagnetic Field with Stark Shift

Entanglement of Two Two-Level Atoms and Two Modes of Electromagnetic Field with Stark Shift

Coupled modes locally interacting with qubits: Critical assessment of the rotating-wave approximation

The interaction of qubits with quantized modes of electromagnetic fields has been largely addressed in the quantum optics literature under the rotating wave approximation (RWA), where rapid oscillating terms in the qubit-mode interaction picture Hamiltonian can be neglected. At the same time, it is generally accepted that provided the interaction is sufficiently strong or for long times, the RWA tends to describe physical phenomena incorrectly. In this work, we extend the investigation of the validity of the RWA to a more involved setup where two qubit-mode subsystems are brought to interaction through their harmonic coordinates. Our treatment is all analytic thanks to a sequence of carefully chosen unitary transformations which allows us to diagonlize the Hamiltonian within and without the RWA. By also considering qubit dephasing, we find that the purity of the two-qubit state presents non-Markovian features which become more pronounced as the coupling between the modes gets stronger and the RWA loses its validity. In the same regime, there occurs fast generation of entanglement between the qubits which is also not correctly described under the RWA. The setup and results presented here clearly show the limitations of the RWA in a scenario amenable to exact description and free from numerical uncertainties. Consequently, it may be of interest for the community working with cavity or circuit quantum electrodynamic systems in the strong coupling regime.

Design of Balanced and Balun Filters Using Dual-Mode Cross-Shaped Dielectric Resonators

In this paper, a dual-mode cross-shaped dielectric resonator (DR) that consists of two identical rectangular DRs is investigated to design balanced and balun bandpass filters (BPFs) for the first time. According to the dominant TE $_{11\delta }$ -mode electromagnetic field of a single rectangular DR, the driven signals for the DR through two probes on the two sides of the DR should be antiphase. Equivalently, the extracted signals from the DR operating at TE $_{11\delta }$ mode are positively out-of-phase. Based on this, a four-port balanced TE $_{11\delta }$ -mode BPF using a single dual-mode DR cavity can be constructed. Furthermore, by converting the balanced BPF into a three-port device, a novel balun BPF using the same DR cavity is designed, showcasing excellent performance of amplitude balance and 180° phase difference. To validate the proposed idea, the balanced and balun BPFs are designed and implemented, respectively. Both of them have a miniaturized circuit size due to the adoption of the dual-mode DR. Good agreement can be obtained between their respective simulated and measured results.

Аттосекундные нанотехнологии: электронные механизмы формирования неравновесных квантовых супра-атомных наноструктур материалов

A theory of one- and two-electron nonequilibrium phenomena on time-spatial levels of quantum supra-atomic nanostructures in materials caused by deep-UV and soft X-ray attosecond pulses is well developed within the fundamental concept of thermal field dynamics. It is shown that time-base sweep of nonequilibrium processes of supra-atomic level formation caused by attosecond pulses starts with the local birth of coherent-entangled static x-gauge modes of two-electron fluctuation electromagnetic fields. The two-electron fluctuation energy accumulates as a quantum electromechanical energy of static x-gauge modes. It results in spontaneous appearance of static electromagnetic loggie 0.1-10 nm in size that include electron pairs and x-gauge modes. Boundaries of the static electromagnetic loggie have kink topological singularities of x-gauge modes in physical space. Finite loggie of coherent-entangled electron pairs enclose Fermi gas of electrons and nuclei and set a topological matrix of quantum electromechanical interfaces in a material. The quantum topology of loggie spatial carriers is a cover of a quantum topology of atoms and single-electron Fermi gas of condensed state.

Forward modeling for “earth-ionosphere” mode electromagnetic field

A fixed artificial source (greater than 200 kW) was used and the source location was selected at a high resistivity region to ensure high emission efficiency. Some publications used the “earth-ionosphere" mode in modeling the electromagnetic (EM) fields with the offset up to a thousand kilometer, and such EM fields still have a signal/noise ratio of 10–20 dB. This means that a new EM method with fixed source is feasible, but in their calculation, the displacement in air was neglected. In this work, some three-layer modeling results were presented to illustrate the basic EM fields’ characteristics in the near, far and waveguide areas under “earth-ionosphere” mode, and a standard is given to distinguish the boundary of near, far and waveguide areas. Due to the influence of the ionosphere and displacement current in the air, the “earth-ionosphere” mode EM fields have an extra waveguide zone, where the fields’ behavior is very different from that of the far field zone.

Quantum Phase and Field Purification for Quantum System in Coherent States Based on Generalized Heisenberg Algebra

In this paper, we consider the interaction between the two-level atom and the electromagnetic field modes initially prepared in coherent states associated with the generalized Heisenberg algebra (GHA). We investigate the dynamical behavior of the field purity, Pancharatnam phase, and atomic-population inversion. Based on the GHA, we study the statistical properties of the field state through the evolution of the Mandel parameter and examine the effects of the initial atomic state setting and the number of transiting photons. The results show that the GHA-coherent-state strength has the potential to affect the time evolution of the field purification, the Pancharatnam phase, and the Mandel parameter.

Compact Feeding Network for Array Radiations of Spoof Surface Plasmon Polaritons.

We propose a splitter feeding network for array radiations of spoof surface plasmon polaritons (SPPs), which are guided by ultrathin corrugated metallic strips. Based on the coupled mode theory, SPP fields along a single waveguide in a certain frequency range can be readily coupled into two adjacent branch waveguides with the same propagation constants. We propose to load U-shaped particles anti-symmetrically at the ends of such two branch waveguides, showing a high integration degree of the feeding network. By controlling linear phase modulations produced by the U-shaped particle chain, we demonstrate theoretically and experimentally that the SPP fields based on bound modes can be efficiently radiated to far fields in broadside direction. The proposed method shows that the symmetry of electromagnetic field modes can be exploited to the SPP transmission network, providing potential solutions to compact power dividers and combiners for microwave and optical devices and systems.

Excitation of the Classical Electromagnetic Field in a Cavity Containing a Thin Slab with a Time-Dependent Conductivity

We derive an exact infinite set of coupled ordinary differential equations describing the evolution of the modes of the classical electromagnetic field inside an ideal cavity containing a thin slab with the time-dependent conductivity σ(t) and dielectric permittivity e(t) for the dispersion-less media. We analyze this problem in connection with the attempts to simulate the so-called dynamical Casimir effect in three-dimensional electromagnetic cavities containing a thin semiconductor slab periodically illuminated by strong laser pulses. Therefore, we assume that functions σ(t) and δe(t) = e(t) − e(0) are different from zero during short time intervals (pulses) only. Our main goal here is to find the conditions under which the initial nonzero classical field could be amplified after a single pulse (or a series of pulses). We obtain approximate solutions to the dynamical equations in the cases of “small” and “big” maximal values of the functions σ(t) and δe(t). We show that the single-mode approximation used in the previous studies can be justified in the case of “small” perturbations, but the initially excited field mode cannot be amplified in this case if the laser pulses generate free carriers inside the slab. The amplification could be possible, in principle, for extremely high maximum values of conductivity and the concentration of free carries (the model of an “almost ideal conductor”) created inside the slab under the crucial condition providing the negativity of the function δe(t). This result follows from a simple approximate analytical solution confirmed by exact numerical calculations. However, the evaluation shows that the necessary energy of laser pulses must be, probably, unrealistically high.

Quantum metamaterials in the microwave and optical ranges

Quantum metamaterials generalize the concept of metamaterials (artificial optical media) to the case when their optical properties are determined by the interplay of quantum effects in the constituent 'artificial atoms' with the electromagnetic field modes in the system. The theoretical investigation of these structures demonstrated that a number of new effects (such as quantum birefringence, strongly nonclassical states of light, etc) are to be expected, prompting the efforts on their fabrication and experimental investigation. Here we provide a summary of the principal features of quantum metamaterials and review the current state of research in this quickly developing field, which bridges quantum optics, quantum condensed matter theory and quantum information processing.

DYNAMICS OF TWO-LEVEL ATOMS INTERACTING WITH THERMAL FIELD FOR ENTANGLED INITIAL ATOMIC STATES

In this paper the entanglement dynamics for system of two two-level atoms interacting with a mode of thermal electromagnetic field in lossless cavity has been investigated. Initial atomic states are the entangled Bell type states. Using the full set of eigenvectors of the Hamiltonian of the considered model we have derived the exact solution for the density matrix for the whole system. On its basis the reduced atomic density matrix and Peres - Horodetcki parameter have been calculated. Calculating of entanglement parameter shows the possibility of high degree of entanglement even for large intensity of thermal field. Thus there is a possibility of maintenance and control over the degree of entanglement.

Polychromatic phase diagram forn-level atoms interacting withℓmodes of an electromagnetic field

A system of $N_a$ atoms of $n$-levels interacting dipolarly with $\ell$ modes of electromagnetic field is considered. The energy surface of the system is constructed from the direct product of the coherent states of U$(n)$ in the totally symmetric representation for the matter times the $\ell$ coherent states of the electromagnetic field. A variational analysis shows that the collective region is divided into $\ell$ zones, inside each of which only one mode of the electromagnetic field contributes to the ground state. In consequence, the polychromatic phase diagram for the ground state naturally divides itself into monochromatic regions. For the case of $3$-level atoms in the $\Xi$-configuration in the presence of $2$ modes, the variational calculation is compared with the exact quantum solution showing that both are in agreement.

Nonclassical properties and quantum resources of hierarchical photonic superposition states

We motivate and introduce a class of "hierarchical" quantum superposition states of $N$ coupled quantum oscillators. Unlike other well-known multimode photonic Schr\"{o}dinger cat states such as entangled coherent states, the hierarchical superposition states are characterized as two-branch superpositions of tensor products of single-mode Schr\"{o}dinger cat states. In addition to analyzing the photon statistics and quasiprobability distributions of prominent examples of these nonclassical states, we consider their usefulness for high-precision quantum metrology of nonlinear optical Hamiltonians and quantify their mode entanglement. We propose two methods for generating hierarchical superpositions in $N=2$ coupled microwave cavities which exploit currently existing quantum optical technology for generating entanglement between spatially separated electromagnetic field modes.

The influence of the classical homogenous gravitational field on interaction of a three-level atom with a single mode cavity field

We study the interaction between a single mode electromagnetic field and a three-level [Formula: see text]-type atom in the presence of a classical homogenous gravitational field when the atom is prepared initially in the momentum eigenstate. The model includes the detuning parameters and the classical homogenous gravitational field. The wave function is calculated by using the Schrödinger equation for a coherent electromagnetic field and an atom is in its excited state. The influence of the detuning parameter and the classical homogenous gravitational field on the temporal behavior of the mean photon number, the normalized second-order correlation function and the normal squeezing is analyzed. The results show that the presence of these parameters has an important effect on these phenomena. The conclusion is reached and some features are given.

Quantum marginal problems

The quantum marginal problem asks the question if elements of a given set of quantum states can be reduced states of some joint quantum state. In this paper we present various versions of the quantum marginal problem along with their solutions in the order in which they were published. The review begins with simple finite-dimensional composite systems and ends with results of the Gaussian quantum marginal problem that apply to systems of harmonic oscillators (e.g. modes of the quantum electromagnetic field).

Classical and quantum correlations in the system of interacting electromagnetic modes

The evolution of Gaussian states of two interacting oscillators corresponding to electromagnetic field modes is studied in the classical and quantum regions. The consideration is performed both in the state representation byWigner functions and in the tomographic probabilistic representation of quantummechanics.Correlations in the two-mode system, in particular, entangled mode states in the quantum region, are considered using the tomographic approach. In the classical region, the states of two modes are described by the density operator which can have negative eigenvalues in this case.

Modeling of Whispering Gallery Modes for Rare Earth Spectroscopic Characterization

A refined model of a mid-IR amplifier, constituted by a tapered chalcogenide fiber coupled to an erbium-doped chalcogenide microsphere, is integrated with a global solution search procedure based on particle swarm optimization approach. It is implemented in a computer code in order to obtain an inversion algorithm useful to evaluate the spectroscopic parameters of rare-earth-doped glass microspheres. The rare earth parameters can be recovered by means of the optical gain measurement. The error in evaluation of the erbium lifetime τ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">41</sub> is <;3.5%. It is <;0.5% for the other lifetimes and ion-ion interaction parameters. These excellent results are obtained since whispering gallery mode electromagnetic field interacts with rare earth for long effective distances.

Estimating the macroanisotropy of a horizontally layered section from controlled-source radiomagnetotelluric soundings

The possibilities of estimating the macroanisotropic parameters of the earth by radiomagnetotelluric soundings with a controlled source in the form of a horizontal electric dipole (a cable with a finite length) are studied in the case of the measurements in the transition zone of the source, where the galvanic and induction modes of the excited electromagnetic field are both important. The forward problem for the considered high frequency band (up to 1000 kHz) is solved with allowance for the displacement currents in the ground and air. The algorithm of anisotropic 1D inversion of the sounding data is presented. The resolution parameters are estimated from the derivatives of the electromagnetic field components with respect to the model parameters. Based on the synthetic examples, it is shown that joint inversion of the impedance and tipper data in the transition zone of the source constrains the space of equivalent models and makes it possible to determine the macroanisotropy coefficient of the section.

Surface lattice resonances and magneto-optical response in magnetic nanoparticle arrays.

Structuring metallic and magnetic materials on subwavelength scales allows for extreme confinement and a versatile design of electromagnetic field modes. This may be used, for example, to enhance magneto-optical responses, to control plasmonic systems using a magnetic field, or to tailor magneto-optical properties of individual nanostructures. Here we show that periodic rectangular arrays of magnetic nanoparticles display surface plasmon modes in which the two directions of the lattice are coupled by the magnetic field-controllable spin–orbit coupling in the nanoparticles. When breaking the symmetry of the lattice, we find that the optical response shows Fano-type surface lattice resonances whose frequency is determined by the periodicity orthogonal to the polarization of the incident field. In striking contrast, the magneto-optical Kerr response is controlled by the period in the parallel direction. The spectral separation of the response for longitudinal and orthogonal excitations provides versatile tuning of narrow and intense magneto-optical resonances.