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S. A. Moiseev

Publications and source records attributed to S. A. Moiseev.

At least 37 records · Page 2Linked to original sources

Spectral-Topological Superefficient Quantum Memory

In this work we report about the fundamental correspondence between the high efficiency of the broadband quantum memory on multifrequency absorbers in the single-mode cavity and the topology of the observed frequency lines. We have found the spectral-topological matching condition by using the multiparametric optimization of the absorber characteristics which makes it possible to improve considerably the spectral efficiency of quantum memory under conditions of a real experiment. The elaborated approach opens the possibility for the creation of the broadband quantum interface consisting of a small number of the absorbers and characterized by the super-high quantum efficiency of more than 99.9%.

quant-ph↗

Broadband Multiresonator Quantum Memory

In this paper we present universal broadband multi-resonator quantum memory (MR-QM) based on the spatial-frequency combs of the microresonators coupled with a common waveguide. Here we found new Bragg-type impedance matching condition for the coupling of the microresonators with a waveguide field which provides an efficient broadband quantum storage. The obtained analytical solution for the microresonator fields enables sustainable parametric control of all the memory characteristics.

physics.optics↗

All-optical photon echo and memory on a chip

We demonstrate that a photon echo can be implemented by all-optical means using an array of on-chip high-finesse ring cavities whose parameters are chirped in such a way as to support equidistant spectra of cavity modes. When launched into such a system, a classical or quantum optical signal -- even a single-photon field -- becomes distributed between individual cavities, giving rise to prominent coherence echo revivals at well-defined delay times, controlled by the chirp of cavity parameters. This effect enables long storage times for high-throughput broadband optical delay and quantum memory.

quant-ph↗

Single photon transfer controlled by excitation phase in a two-atom cavity system

We investigate the quantum interference effects of single photon transfer in two-atom cavity system caused by external excitation phase. In the proposed system, two identical atoms (with different positions in the optical cavity) are firstly prepared into a timed state by an external single photon field. During the excitation, the atoms grasp different phases which depend on the spatial positions of the atoms in the cavity. Due to strong resonant interaction between two atoms and optical cavity mode the absorbed input photon can be efficiently transferred from the atoms to the resonant cavity mode. We show that the quantum transfer is highly sensitive to the external excitation phases of atoms and it leads to quantum interference effects on the cavity mode excitation. Besides, the quantum transfer is also influenced by the dipole-dipole interaction dependent to the atomic distance. In this system the atomic positions also determine the coupling constants between atoms and cavity mode which causes additional interference effects to the photon exchange between atoms and cavity. Based on the characteristics of excitation phase we find that it is a feasible scheme to generate long-lived dark state and it could be useful for storage and manipulation of single photon fields by controlling the excitation phase.

quant-ph↗

Thermalization and long-lived quantum memory in the multi-atomic ensembles

We have studied the role of thermalization in lifetime reduction of quantum memory based on multi-atomic ensembles. Herein, it is shown to be impossible to remove the thermaization-caused decoherence in such systems using the methods of dynamical decoupling. We have analyzed the existing models of the thermalization and have proposed a new understanding of the thermalization as a result of the internal processes which are not described in the unitary quantum dynamics formalism. The possible ways for reducing the negative influence of thermalization on the quantum memory lifetime are also discussed.

quant-ph↗

An analytical solution for light field modes in waveguides with nonideal cladding

We have obtained an analytical solution for the dispersion relation of the light field modes in the nanowaveguide structure. The solution has been analyzed for the planar waveguide with metamaterial claddings and dielectric core. The analytical solution is valid within the broadband spectral range and is confirmed by existing numerical calculations. The developed theoretical approach opens vast possibilities for the analytical investigations of the light fields in the various waveguides.

physics.optics↗

Short cycle pulse sequence for dynamical decoupling of local fields and dipole-dipole interactions

We propose a new pulse sequence for dynamical averaging of the dipole-dipole interactions and inhomogeneities of the magnetic fields in the nuclear spin system. The sequence contains a short cycle of the periodic resonant pulse excitation that offers new possibilities for implementing the long-lived multi-qubit quantum memory on the condensed spin ensembles that are so important for construction of universal quantum computer and long-distance quantum communications.

quant-ph↗

Multi-qubit time-bin quantum RAM

We have proposed a scheme of multi-qubit \textit{quantum random access memory} (qRAM) based on the impedance matched photon echo quantum memory incorporated together with the control three-level atom in two coupled QED cavities. A set of matching conditions for basic physical parameters of the qRAM scheme that provides an efficient quantum control of the fast single photon storage and read-out has been found. In particular, it was found that the qRAM operation is determined by the properties of the photonic molecular realized in the qRAM dynamics. Herein, the maximal efficiency of the qRAM is achieved when the cooperativety parameter of the photonic molecular equals to unity that can be easily experimentally implemented. The quantum address of the stored photonic qubits can be put into practice when the address is encoded in photonic multi-time-bin state. We discuss the advantages of the qRAM in terms of working with multi-qubit states and the implementation by current quantum technologies in the optical and microwave domains.

quant-ph↗

Stationary and quasi-stationary light pulse in three-level cold atomic system

We have studied stationary and quasi-stationary signal light pulses in cold lambda-type atomic media driven by counterpropagating control laser fields at the condition of electromagnetically induced transparency. By deriving a dispersion relation we present spectral and temporal properties of the signal light pulse and a significant influence of atomic decoherence on the coupled stationary light pulses for spatial splitting. Finally we discuss quasi-stationary light pulse evolution characterized by frozen spatial spreading for a robust coherent control of slow light pulses.

physics.optics↗

Scalable time reversal of Raman echo quantum memory and quantum waveform conversion of light pulse

We have found a new hidden symmetry of time reversal light-atom interaction in the photon echo quantum memory with Raman atomic transition. The time-reversed quantum memory creates generalized conditions for ideal compression/decompression of time duration of the input light pulses and its wavelength. Based on a general analytical approach to this scheme, we have studied the optimal conditions for the light field compression/decompression in resonant atomic systems characterized by realistic spectral properties. The demonstrated necessary conditions for the effective quantum conversion of the light waveform and wavelength are also discussed for various possible realizations of the quantum memory scheme. The performed study promises new capabilities for fundamental study of the light-atom interaction and deterministic quantum manipulation of the light field, significant for quantum communication and quantum computing.

quant-ph↗

Off-resonant Raman echo quantum memory on atoms with natural inhomogeneous broadening in optical QED cavity

A new scheme of photon echo based quantum memory in the optimal optical QED cavity with off-resonant Raman atomic transition is proposed. The scheme employs the atomic ensembles characterized by an optically thin resonant transition and natural inhomogeneous broadening of the resonant line composed of the arbitrary narrow homogeneous spectral components. The scheme provides robust and quite simple coherent control of the light-atoms dynamics that can be implemented by using an existing optical technique and opens a practical way for realization of the efficient long-lived multi-mode optical quantum memory.

quant-ph↗

Quantum computer with atomic logical qubits encoded on macroscopic three-level systems in common quantum electrodynamic cavity

We propose an effective realization of the universal set of elementary quantum gates in solid state quantum computer based on macroscopic (or mesoscopic) resonance systems - multi-atomic coherent ensembles, squids or quantum dots in quantum electrodynamic cavity. We exploit an encoding of logical qubits by the pairs of the macroscopic two- or three-level atoms that is working in a Hilbert subspace of all states inherent to these atomic systems. In this subspace, logical single qubit gates are realized by the controlled reversible transfer of single atomic excitation in the pair via the exchange of virtual photons and by the frequency shift of one of the atomic ensembles in a pair. In the case of two-level systems, the logical two - qubit gates are performed by the controlling of Lamb shift magnitude in one atomic ensemble, allowing/blocking the excitation transfer in a pair, respectively, that is controlled by the third atomic system of another pair. When using three-level systems, we describe the NOT-gate in the atomic pair controlled by the transfer of working atomic excitation to the additional third level caused by direct impact of the control pair excitation. Finally, we discuss advantages of the proposed physical system for accelerated computation of some useful quantum gates.

quant-ph↗

Magnon qubit on double Bose-Einstein condensate

We have proposed a magnon qubit based on coupled configuration of Bose-Einstein condensates (BEC) in two ferromagnetic samples placed closely to each other. We have evaluated the magnon BEC qubit realization in the double BEC scheme where we found a quantum synchronism condition providing an effective Hamiltonian of magnon qubit. It has the form of well-known superconducting Josephson qubit. The possibilities for coherent magnon BEC qubit rotation are analyzed. Implementations of the magnon BEC qubit are considered for small samples and thin ferromagnetic films. Advantages of the proposed macroscopic qubit realization are discussed.

quant-ph↗

Atomic Frequency Comb storage as a slow-light effect

Atomic Frequency Comb (AFC) protocol has been particularly successful recently to demonstrate the storage of quantum information in a solid medium (rare-earth doped crystals). The AFC is inspired by the photon-echo technique. We show in this paper that the AFC is actually closely related to the slow-light based storage protocols extensively used in atomic vapours. Experimental verifications are performed in thulium doped YAG (Tm3+:YAG). We clarify the interplay between absorption and dispersion and propose a classification of the existing protocols.

quant-ph↗

Trajectory-Wave Approach to Electron Dynamics in Hydrogen Atom

In this work we propose a new approach to the explanation of the nature of electron based on the corpuscular-wave monism using the further development of the optical-mechanical analogy to describe the physical reality. In this theory the motion of an electron is considered to occur along a trajectory the presence of which is a reflection of the existence of a particle, as well as it is assumed that any motion is defined by a wave V(x,t). It is assumed that there is an explicit relationship between the trajectory and wave equations of the electron, which are established on the basis of the local variational principle. In this approach, an electron wave propagating in free space takes along the electron trajectory. We used this theory to describe the electron motion in a hydrogen-like atom and found its stationary states. The energies of these states coincide with the known quantum mechanics solutions for the stationary energies of the hydrogen-like atom, however, in our approach the spatial trajectories of the electron have the form of the surfaces, which are formed in the region of nodes of the standing electron wave. These surfaces have the form of spheres for the spherical symmetrical electron states and the radii of these spheres coincide with the radii of the Bohr orbits of these states. Thus, in this approach the trajectory and wave measurements of the electron get a consistent spatial description that is inherent to the picture of the corpuscular-wave monism. We discuss the considerable correspondence of the proposed theory with the quantum mechanics results describing the stationary and non-stationary motions of the electron in the atom and their difference. We believe that measuring of the spatial configuration of the observed electron trajectory surfaces in an atom could be a deep examination of the standard quantum theory.

quant-ph↗

Temporal compression of quantum information-carrying photons using a photon-echo quantum memory approach

We study quantum compression and decompression of light pulses that carry quantum information using a photon-echo quantum memory technique with controllable inhomogeneous broadening of an isolated atomic absorption line. We investigate media with differently broadened absorption profiles, transverse and longitudinal, finding that the recall efficiency can be as large as unity and that the quantum information encoded into the photonic qubits can remain unperturbed. Our results provide new insight into reversible light-atom interaction, and are interesting in view of future quantum communication networks, where pulse compression and decompression may play an important role to increase the qubit rate, or to map quantum information from photonic carriers with large optical bandwidth into atomic memories with smaller bandwidth.

quant-ph↗

Multi mode nano scale Raman echo quantum memory

Low loss magnetic surface plasmon polariton (SPP) modes characterized by enhanced electrical field component and subwavelength confinement on the dielectric and negative-index metamaterial interface are presented. We demonstrate a possibility of storage and perfect retrieval of the low loss magnetic SPP fields by using a photon echo quantum memory on Raman atomic transition. We describe specific properties of the proposed technique which opens a possibility for efficient nano scale multi-mode quantum memory.

quant-ph↗