On the Teleportation of Continuous Variable

The measurement procedures used in quantum teleportation are analyzed from the viewpoint of the general theory of quantum-mechanical measurements. It is shown that to find the teleported state one should only know the identity resolution (positive operator-valued measure) generated by the corresponding instrument (quantum operation describing the system state change caused by the measurement) rather than the instrument itself. A quantum teleportation protocol based on a measurement associated with a non-orthogonal identity resolution is proposed for a system with non-degenerate continuous spectrum.Comment: 13 pages, no figures. To be published in JET

Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are incompatible with the theory of ion acoustic waves. The estimate for the pressure in a strongly coupled Coulomb system and a scaling law for the complex plasma make it possible to derive an evaluation for the speed of sound, which is in a reasonable agreement with the experiments in complex plasmas.Comment: 5 pages, 2 figures, 1 tabl

Resonant electron transfer between quantum dots

An interaction of electromagnetic field with a nanostructure composed of two quantum dots is studied theoretically. An effect of a resonant electron transfer between the localized low-lying states of quantum dots is predicted. A necessary condition for such an effect is the existence of an excited bound state whose energy lies close to the top of the barrier separating the quantum dots. This effect may be used to realize the reversible quantum logic gate NOT if the superposition of electron states in different quantum dots is viewed as the superposition of bits 0 and 1.Comment: 8 pages, 1 EPS-figure, submitted to Phys. Rev.

Nuclear magnetic resonance spectrum of 31P donors in silicon quantum computer

The influence of the electric field created by a gate potential of the silicon quantum computer on the hyperfine interaction constant (HIC) is obtained. The errors due to technological inaccuracy of location of donor atoms under a gate are evaluated. The energy spectra of electron-nuclear spin system of two interacting donor atoms with various values of HIC are calculated. The presence of two pairs of anticrossing levels in the ground electronic state is shown. Parameters of the structure at which errors rate can be greatly minimized are found.Comment: 12 pages,, 3 figure

Auto parts market in the context of legalization of parallel imports

The article assesses the share of counterfeit products on the Russian domestic market highlighting the most counterfeited product categories. On the basis of the analysis of key indicators of the automotive parts market, preconditions for the presence of large volumes of counterfeit products in the segment have been identified. Correlation of parallel imports and the counterfeit auto parts number increase has been established. The paper presents recommendations for combating the importation of counterfeit products in the context of parallel imports. The most significant of them are the extension of digital labeling to a wide category of automotive components, establishment of domestic production of spare parts and components, stimulation of Russian manufacturers by providing targeted loans and tax incentives