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B. Vlahovic

Publications and source records attributed to B. Vlahovic.

33 records · Page 2Linked to original sources
arXiv2011

Electron localizations in double concentric quantum ring

We investigate the electron localization in double concentric quantum rings (DCQRs) when a perpendicular magnetic field is applied. In weakly coupled DCQRs, the situation can occur when the single electron energy levels associated with different rings may be crossed. To avoid degeneracy, the anti-crossing of these levels has a place. We show that in this DCQR the electron spatial transition between the rings occurs due to the electron level anti-crossing. The anti-crossing of the levels with different radial quantum numbers provides the conditions for electron tunneling between rings. To study electronic structure of the semiconductor DCQR, the single sub-band effective mass approach with energy dependence was used. Results of numerical simulation for the electron transition are presented for DCQRs of geometry related to one fabricated in experiment.

quant-ph↗
arXiv2011

Electron Transfer between Weakly Coupled Concentric Quantum Rings

The electronic structure of the semiconductor double concentric quantum nano-ring (DCQR) is studied under the single sub-band effective mass approach. We show that in the weakly coupled DCQR, that has been placed in transverse magnetic field, the electron spatial transition between the rings can occur due to electron level anti-crossing. The anti-crossing of the levels with different radial quantum numbers provides the conditions when the electron tunneling between rings becomes possible. Results of numerical simulation for the electron transition are presented for DCQRs of different geometry. In particularly, the system of a QR with a QD located at center of this QR is considered.

cond-mat.mes-hall↗
arXiv2010

A study of nucleon-deuteron elastic scattering in configuration space

A new computational method for solving the nucleon-deuteron breakup scattering problem has been applied to study the elastic neutron- and proton-deuteron scattering on the basis of the configuration-space Faddeev-Noyes-Noble-Merkuriev equations. This method is based on the spline-decomposition in the angular variable and on a generalization of the Numerov method for the hyperradius. The Merkuriev-Gignoux-Laverne approach has been generalized for arbitrary nucleon-nucleon potentials and with an arbitrary number of partial waves. The nucleon-deuteron observables at the incident nucleon energy 3 MeV have been calculated using the charge-independent AV14 nucleon-nucleon potential including the Coulomb force for the proton-deuteron scattering. Results have been compared with those of other authors and with experimental proton-deuteron scattering data.

nucl-th↗
arXiv2009

Electronic and Level Statistics Properties of Si/SiO2 Quantum Dots

Spherical shaped Si quantum dots (QDs) embedded into the SiO2 substrate are considered in the single sub-band effective mass approach. Nonparabolicity of the Si conduction band is described by the energy dependence of electron effective mass. Calculations of low-lying single electron and hole energy levels are performed. For small sizes QD (diameter D<6nm) there is a strong confinement regime when the number of energy levels is restricted to several levels. The first order of the perturbation theory is used to calculate neutral exciton recombination energy taking into account the Coulomb force between electron and heavy hole. The PL exciton data are reproduced well by our model calculations. For weak confinement regime (size D>10 nm), when the number of confinement levels is limited by several hundred, we considered the statistical properties of the electron confinement. Distribution function for the electron energy levels is calculated and results are discussed.

cond-mat.mes-hall↗
arXiv2007

A Pair Polarimeter for Linearly Polarized High Energy Photons

A high quality beam of linearly polarized photons of several GeV will become available with the coherent bremsstrahlung technique at JLab. We have developed a polarimeter which requires about two meters of the beam line, has an analyzing power of 20% and an efficiency of 0.02%. The layout and first results of a polarimeter test on the laser back-scattering photon beam at SPring-8/LEPS are presented.

physics.ins-det↗
arXiv2006

Two-jet inclusive cross sections in heavy-ion collisions in the perturbative QCD

In the framework of perturbative QCD, double inclusive cross sections for high $p_t$ parton production in nucleus-nucleus collisions are computed with multiple rescattering taken into account. The induced long-range correlations between numbers of jets at forward and backward rapidities are found to reach $10÷20$% for light nuclei at $\sqrt{s}=200$ GeV/c and to be suppressed for heavy nuclei and LHC energies.

hep-ph↗
arXiv2006

Atomic States Entanglement in Carbon Nanotubes

The entanglement of two atoms (ions) doped into a carbon nanotube has been investigated theoretically. Based on the photon Green function formalism for quantizing electromagnetic field in the presence of carbon nanotubes, small-diameter metallic nanotubes are shown to result in a high degree of the two-qubit atomic entanglement for long times due to the strong atom-field coupling.

cond-mat.mes-hall↗
arXiv2006

Optical absorbtion by atomically doped carbon nanotubes

We analyze optical absorption by atomically doped carbon nanotubes with a special focus on the frequency range close to the atomic transition frequency. We derive the optical absorbtion line-shape function and, having analyzed particular achiral nanotubes of different diameters, predict the effect of absorbtion line splitting due to strong atom-vacuum-field coupling in small-diameter nanotubes. We expect this effect to stimulate relevant experimental efforts and thus to open a path to new device applications of atomically doped carbon nanotubes in modern nanotechnologies.

cond-mat.mes-hall↗
arXiv2003

Subthreshold photoproduction of charm

Charm photoproduction rates off nuclei below the nucleon threshold are estimated using the phenomenologically known structure functions both for x>1 and x<1. The rates rapidly fall below the threshold from values of the order 10 pb for Pb close to the threshold (at 7.5 GeV) down to values of the order 1 pb at 6 GeV.

hep-ph↗
arXiv2003

Leptoproduction of nucleons in the cumulative region

Leptoproduction of nucleons into the backward hemisphere on nuclear targets is studied at relativistic subasymptotic energies and momenta. The relativistic internucleon potential is extracted from appropriate photoproduction data. Different production mechanisms are found to work together and interfere. Whenever rescattering is kinematically possible, it gives the bulk of the contribution, except at very high Q^2. Comparison with the existing data at E=2.4 GeV shows a reasonable agreement.

hep-ph↗
arXiv2002

Estimates of the subthreshold production of charm

Charm photoproduction rates off nuclei below the nucleon threshold are estimated using the phenomenologically known structure functions both for $x<1$ and $x>1$. The rates rapidly fall from values of the order 1 nb at the threshold to values of the order 1 pb at 6 GeV for Pb target.

hep-ph↗
arXiv2002

Cumulative structure function in terms of nucleonic wave function of the nucleus

The structure function of the nucleus in the cumulative region $x>1$ is studied in terms of nucleon degrees of freedom. At high $Q^2$ the resulting expressions are presented as a sum of contributions from few-nucleon correlations. Two-nucleon correlations are studied in some detail. Spin variables are averaged out. In the region $1<x<2$ the structure functions are calculated for the relativistic interaction proposed by F.Gross {\it et al}. They are found to fall with $x$ faster than the exponential. For Carbon at $x=1.05$, where the method is not rigorously applicable, they turn out to be rougly twice larger than the experimental data.

nucl-th↗