The photodetection process under the conditions of an imperfect measurement device

There may be a link between the quantum properties of the vacuum and the parameters describing the properties of light propagation, culminating in a sum over all types of elementary particles existing in Nature weighted only by their squared charges and independent of their masses. The estimate for that sum is of the order of 100.     

Resonance Properties of a Low-Pressure Dielectric Barrier Discharge

Technical Physics - The electrical characteristics of a dielectric barrier discharge (DBD) symmetrical actuator at low pressures gave been investigated. A power source–actuator–DBD...     

Semiclassical Trajectory-Coherent Approximations of Hartree-Type Equations

We use the concept of the complex WKB–Maslov method to construct semiclassically concentrated solutions for Hartree-type equations. Formal solutions of the Cauchy problem for this equation that are asymptotic (with respect to a small parameter , 0) are constructed with the power-law accuracy O(^N/2), where N3 is a positive integer. The system of Hamilton–Ehrenfest equations (for averaged and centered moments) derived in this paper plays a significant role in constructing semiclassically concentrated solutions. In the class of semiclassically concentrated solutions of Hartree-type equations, we construct an approximate Green's function and state a nonlinear superposition principle.     

Nonlinear optical properties of a medium with <Emphasis Type="Italic">M</Emphasis>-configuration of atomic levels

Nonlinear effects related to the resonant interaction of electromagnetic fields that act on four transitions of a five-level M scheme of atomic levels in the stationary limit are studied. Eight stationary solutions that depend on the state of circular polarizations of three operating classical modes of the field are found for the atomic density matrix. To decrease the absorption of the fields on the atomic transitions, the regime of electromagnetically induced transparency is used. The conditions under which the M scheme is close in its optical properties to two- or three-level schemes are found. Based on the obtained eight solutions, the total accumulated phase shifts of the working waves are calculated. It is shown that the M scheme can perform the operation of double controlled phase shift. Alternatively to the method proposed, this operation also can be carried out using five two-qubit operations, which reduces its noise immunity.     

Coupled dielectric waveguides with photonic crystal properties

A system of planar waveguides coupled through a periodic set of small windows is considered. It is shown that the weak periodic coupling of the waveguides leads to an additional eigenvalue band separated by a gap from the threshold of a continuous spectrum branch. Thus, the system has photonic crystal properties, which can be used to construct optical fiber devices. This system can also play the role of a SCISSOR device for reducing the group velocity of light, in optical delay lines, etc.     

Controlled hysteresis in optical systems surrounded by two feedback loops

The absorptive bistability in a nonlinear optical system surrounded by two feedback loops is studied. The role of the nonlinear element is played by a cell with Λ-type atom vapors placed in a unidirectional ring cavity. The feedback includes two electromagnetic fields interacting with two atomic transitions. A two-dimensional domain of stability was found in the coordinates of field intensities at the input. The dependence of its shape on the values of different parameters of the optical system is studied. The input-output curves corresponding to different trajectories in the domain of stability are obtained.     

Possible implementation of CNOT and CCNOT gates

The quantum optical gate CCNOT based on five level atomic scheme is discussed. The qubits are encoded in polarization properties of three optical beams. The nonlinear cross Kerr effect is used for getting nonlinear phase shifts in these beams. A way of CNOT implementation using coupled double quantum wells is suggested. The device is described in the framework of the model based on the operator extensions theory.