Multiphoton excitation and high-harmonics generation in topological insulator.

Multiphoton interaction of coherent electromagnetic radiation with 2D metallic carriers confined on the surface of the 3D topological insulator is considered. A microscopic theory describing the nonlinear interaction of a strong wave and metallic carriers with many-body Coulomb interaction is developed. The set of integrodifferential equations for the interband polarization and carrier occupation distribution is solved numerically.

Microscopic nonlinear relativistic quantum theory of absorption of powerful x-ray radiation in plasma.

The microscopic quantum theory of plasma nonlinear interaction with the coherent shortwave electromagnetic radiation of arbitrary intensity is developed. The Liouville-von Neumann equation for the density matrix is solved analytically considering a wave field exactly and a scattering potential of plasma ions as a perturbation. With the help of this solution we calculate the nonlinear inverse-bremsstrahlung absorption rate for a grand canonical ensemble of electrons.

Self-amplified gamma-ray laser on positronium atoms from a Bose-Einstein condensate.

A scheme of an intense coherent gamma-ray source based on the spontaneous radiation of positronium atoms in a Bose-Einstein condensate (BEC) due to two-photon collective annihilation decay is investigated analytically arising from the second quantized formalism. It is shown that because of the intrinsic instability of annihilation decay of BEC, the spontaneously emitted entangled photon pairs are amplified, leading to an exponential buildup of a macroscopic population into end-fire modes at a certain shape of the elongated condensate. The considered scheme may also be applied to a BEC of atoms or quasiparticles as a laser mechanism with double coherence to create entangled photonic beams with a macroscopic number of photons.

[Markers of apoptotic dysfunction in schizophrenia].

According to modern concepts, alterations of the apoptosis processes and its genetic regulation are involved in etiopathogenesis of schizophrenia. This is observed on the levels of both the brain and peripheral blood. However, studies in this aspect are on initial stage of development, and molecular and cellular mechanisms of abnormalities of apoptosis in schizophrenia are not clear.

[The involvement of abnormal apoptosis in the disturbance of synaptic plasticity in posttraumatic stress disorder].

Authors determined the levels of marker proteins for apoptosis and synaptic plasticity - annexin-А5 and complexin-2, correspondingly, as well as the proinflammatory cytokine tumor necrosis factor-α (TNF-α) in the blood serum of patients with posttraumatic stress disorder (PTSD) in comparison to healthy controls using the enzyme-linked immunosorbent assay. An analysis of correlations between these parameters was performed. According to the results obtained, the levels of annexin-А5 and complexin-2 were significantly lower, and the levels of TNF-α were significantly higher in PTSD patients.