[en] The master equation for a regularly pumped laser with coherent injection has been numerically solved using quantum trajectories. The onset of quadrature squeezing of the intracavity light has been observed. The case where the injection is switched well after the pumping has been considered.

[en] Many interesting nonlinear effects are based on the strong interaction of motional degrees of freedom of atoms with an optical cavity field. Among them is the spatial self-organization of atoms in a pattern where the atoms group in either odd or even sites of the cavity-induced optical potential. An experimental observation of this effect can be simplified by using, along with the original cavity-induced feedback, an additional electronic feedback based on the detection of light leaking the cavity and the control of the optical potential for the atoms. Following our previous study, we show that this approach is more efficient from the laser power perspective than the original scheme without the electronic feedback

No abstract available

[en] We consider the problem of suppression of noise acting on atomic ensembles trapped in optical lattices in the low-energy limit. Noise affecting external degrees of freedom of each atom independently and noise influencing only the center-of-mass (c.m.) mode of the ensemble are addressed. Taking into account the quantum character of the atomic motion, we show that negative feedback loop acting on the c.m. coordinate of the atomic ensemble is able to partially compensate both noise sources mentioned above

[en] The Bloch equation in the Heisenberg–Weyl group is considered. A λ-representation of the Lie algebra of a Heisenberg–Weyl group of arbitrary dimensionality is constructed, and an expression for the statistical sum in the Heisenberg–Weyl group is obtained. Expressions for the statistical sum of the Heisenberg–Weyl group and other thermodynamic quantities are analyzed.

[en] Continuous center-of-mass position measurements performed on an interacting harmonically trapped Bose-gas are considered. Using both a semianalytical mean-field approach and a completely quantum numerical technique based on the positive P representation, it is demonstrated that the atomic delocalization due to the measurement backaction is smaller for a strongly interacting gas. The numerically calculated second-order correlation functions demonstrate the appearance of atomic bunching as a result of the center-of-mass measurement. Although rather small, the bunching is also present for a strongly interacting gas, which is in contrast with the case of an unperturbed gas. The performed analysis allows us to speculate that, for relatively strong interactions, the size of the atomic cloud determined with a single snapshot measurement can become smaller than the ground-state cloud size.

[en] A new approach to feedback cooling of many-particle ensembles is considered. The homodyne detection of counter-propagating probe beams is shown to provide enough information to realize an efficient ‘bang-bang’ cooling algorithm. The feasibility of the method is demonstrated via numerical Monte Carlo simulations of classical trajectories of the particles taking into account the spontaneous emission noise. The numerical analysis and approximate theoretical treatment predict the cooling rate as being inverse proportional to the square root of the number of particles in the ensemble. (paper)

[en] We propose and numerically analyze a new method of cooling for generic polarizable particles. It combines the ideas of cavity self-organization and feedback cooling. In particular, we propose to control the periodic potential for the atoms using the Bragg back-reflection of the probe light. The feedback loop is designed to maximize the reflection, which corresponds to tight localization of the atoms in the potential wells. The model, with realistic parameters, has been numerically simulated and found to demonstrate pronounced cooling and spatial localization effects. On the basis of the same numerical simulations, the time scale of the cooling process was shown to be comparable to the trapping time in conventional dipole traps. (paper)

[en] In this work, a new method of background subtraction in XPS is suggested considering multiple inelastic scattering in a multilayer inhomogeneous target. The method is based on solution of the problem of multiple inelastic photoelectron scattering in a multilayer plane-parallel target. For a overlayer/substrate system, formulae for subtraction of background generated by multiple inelastic photoelectron scattering are found. It is shown that backgroundы of a spectral line of photoelectrons emitted from the overlayer and emitted from the substrate and inelastically scattered in the overlayer differ significantly. (paper)

[en] The Department of General physics and nuclear fusion, National Research University “Moscow Power Engineering Institute”, developed a set of tests (over 1000 questions) for the current control of knowledge of students in the section “Electricity and magnetism” of the General physics course using the internet distance learning system “Prometheus” (fourth generation). Under this section of the proposed test tasks are divided into sections corresponding to the topics section. These tasks include quality issues, design tasks, tasks with a choice of answers (one of many, many of many), the job with the selection region in the figure, tasks with detailed answer. The variety of tasks allows the teacher not only to objectively assess the student acquired knowledge but also to develop his problem-solving skills, to learn to be fluent in theory. The results of testing conducted for several years, show the high interest of students in the repeated independent execution of tasks and correlate well with the results of intermediate certification (exams). (paper)