Results for "A. K. Petukhov"

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Electron paramagnetic resonance detected via magnetization measurementsFeb 07 2005Presented are magnetization measurements on a crystal of Fe8 single-molecule magnets using a Hall probe magnetometer. Irradiation with microwaves at frequencies of 92 and 110-120 GHz leads to the observation of electron paramagnetic resonance (EPR) detected ... More
Comments on "Limits on possible new nucleon monopole-dipole interactions from the spin relaxation rate of polarized $^3$He gas"Mar 09 2011In the article "Limits on possible new nucleon monopole-dipole interactions from the spin relaxation rate of polarized $^3$He gas", new limits on short-range, Axion-like interactions are presented. In this comment it is shown that the theoretical treatement ... More
Polarized 3He as a probe for short-range spin-dependent interactionsSep 17 2010Oct 19 2010We have studied the relaxation of a spin-polarized gas in a magnetic field, in the presence of short-range spin-dependent interactions. As a main result we have established a link between the specific properties of the interaction and the dependence of ... More
Constraining short-range spin-dependent forces with polarized helium 3 at the Laue-Langevin InstituteOct 09 2015We have searched for a short-range spin-dependent interaction mediated by a hypothetical light scalar boson with CP-violating couplings to the neutron using the spin relaxation of hyperpolarized $^3$He. The walls of the $^3$He cell would generate a depolarizing ... More
Universality of spin-relaxation for spin 1/2 particles diffusing over magnetic field inhomogeneities in the adiabatic regimeMar 19 2014Jun 08 2014We present a theoretical analysis of spin relaxation, for a polarized gas of spin 1/2 particles undergoing restricted adiabatic diffusive motion within a container of arbitrary shape, due to magnetic field inhomogeneities of arbitrary form.
Observation of strong surface state effects in the nonlinear magneto-optical response of Ni(110)Jan 26 2000Spectroscopic magnetization induced optical Second Harmonic Generation (MSHG) measurements from a clean Ni(110) surface reveal strong resonance effects near 2.7 eV that can be attributed to the presence of an empty surface state. The good agreement with ... More
On the Mass Eigenstate Composition of the 8B Neutrinos from the SunAug 14 2006Apr 19 2007The present data of gallium experiments provide indirectly the only experimental limit on the fraction of $\nu_2$ mass eigenstate for the $^8$B neutrinos from the Sun. However, if to use the experimental data alone, the fraction of $\nu_2$ and, consequently, ... More
Homogeneous projective varieties with semi-continuous rank functionApr 11 2013Apr 06 2015Let $\mathbb X\subset\mathbb P(V)$ be a projective variety, which is not contained in a hyperplane. Then every vector $v$ in $V$ can be written as a sum of vectors from the affine cone $X$ over $\mathbb X$. The minimal number of summands in such a sum ... More
Neutrino fluxes from CNO cycle in the Sun in the non stationary case with mixingFeb 13 2009The computational analyses is presented of the non stationary case with mixing of the solar model when the neutrino flux $F_{13}$ from the decay of $^{13}N$ is higher than a standard solar model predicts
Prospects for studying the solar CNO cycle by means of a lithium neutrino detectorJun 03 2008Oct 09 2008Lithium detectors have a high sensitivity to CNO neutrinos from the Sun. The present experimental data and prospects for future experiments on the detection of CNO neutrinos are discussed. A nonstationary case is considered when the flux of 13N neutrinos ... More
Annihilators of highest weight $\frak{sl}(\infty)$-modulesOct 30 2014We give a criterion for the annihilator in U$(\frak{sl}(\infty))$ of a simple highest weight $\frak{sl}(\infty)$-module to be nonzero. As a consequence we show that, in contrast with the case of $\frak{sl}(n)$, the annihilator in U$(\frak{sl}(\infty))$ ... More
Neutrinos from CNO cycle at the present epoch of the solar neutrino researchOct 27 2009The importance of the study of solar neutrinos generated in CNO cycle is discussed in view of the presently obtained data. The emphasis is given to the precise detemination of the flux of low energy pp-neutrinos as a main topic of future experimental ... More
Centrifugal quantum states of neutronsJun 24 2008We propose a method for observation of the quasi-stationary states of neutrons, localized near the curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror Fermi-potential. This phenomenon is an example ... More
Reconstructions of diamond (100) and (111) surfaces: Accuracy of the Brenner potentialMar 14 2000We present a detailed comparison of the structural predictions of the effective many-body Brenner potential with those of ab-initio studies for known reconstructions of diamond (100) and (111) surfaces. These results suggest high reliability of the Brenner ... More
Scattering by Atomic Spins and Magnetoresistance in Dilute Magnetic SemiconductorsFeb 20 2007We studied electrical transport in magnetic semiconductors, which is determined by scattering of free carriers off localized magnetic moments. We calculated the scattering time and the mobility of the majority and minority-spin carriers with both the ... More
Low-Frequency Optical Properties of $β^{\prime\prime}$-(BEDO- TTF)$_5$[CsHg(SCN)$_4$]$_2$: Indications of Electronic Correlations in a 1/5-Filled Two-Dimensional ConductorSep 17 2003The polarized reflectivity of $\beta^{\prime\prime}$-(BEDO-TTF)$_5$[CsHg(SCN)$_4$]$_2$ is studied in the infrared range between 60 cm-1 and 6000 cm-1 from room temperature down to 10 K. Already at T=300 K a pseudogap in the optical conductivity is present ... More
Magnetization dynamics in the single-molecule magnet Fe8 under pulsed microwave irradiationJan 15 2007We present measurements on the single molecule magnet Fe8 in the presence of pulsed microwave radiation at 118 GHz. The spin dynamics is studied via time resolved magnetization experiments using a Hall probe magnetometer. We investigate the relaxation ... More
Advanced broad-band solid-state supermirror polarizers for cold neutronsJun 06 2016Jun 15 2016An ideal solid-state supermirror (SM) neutron polarizer assumes total reflection of neutrons from the SM coating for one spin-component and total absorption for the other, thus providing a perfectly polarized neutron beam at the exit. However, in practice, ... More
A project of advanced solid-state neutron polarizer for PF1B instrument at ILLJun 11 2019Among Super-Mirror (SM) polarizers, solid-state devices have many advantages. The most relevant is 5-10 times smaller length compared to air-gap polarizers allowing to apply stronger magnetic fields. An important condition for a good SM polarizer is the ... More
Quantum motion of a neutron in a wave-guide in the gravitational fieldDec 16 2005Feb 04 2006We study theoretically the quantum motion of a neutron in a horizontal wave-guide in the gravitational field of the Earth. The wave-guide in question is equipped with a mirror below and a rough absorber above. We show that such a system acts as a quantum ... More
A quantum mechanical description of the experiment on the observation of gravitationally bound statesFeb 10 2006Feb 20 2006Quantum states in the Earth's gravitational field were observed, when ultra-cold neutrons fall under gravity. The experimental results can be described by the quantum mechanical scattering model as it is presented here. We also discuss other geometries ... More
The number of master integrals is finiteApr 23 2010May 06 2010For a fixed Feynman graph one can consider Feynman integrals with all possible powers of propagators and try to reduce them, by linear relations, to a finite subset of integrals, the so-called master integrals. Up to now, there are numerous examples of ... More
A Search for Hidden Photon CDM in a Multi-Cathode Counter (MCC) dataJan 10 2016A search for hidden photon cold dark matter in a mass range from 5 to 500 eV in data collected during 60 days in November and December, 2015 by a Multi-Cathode Counter (MCC) is reported. From the analyses of this data we found no evidence for the existence ... More
Search for Hidden Photon Dark Matter Using a Multi-Cathode CounterDec 10 2018A search for hidden-photon (HP) dark matter using a multi-cathode counter is reported. The technique based on counting of single electrons emitted from outer cathode of the proportional counter by hidden-photons was used. The apparatus and the calibration ... More
Results from a Hidden Photon Dark Matter Search Using a Multi-Cathode CounterJan 25 2019Jun 20 2019Here we present measurements of the rates of emission of single electrons from the cathode of a proportional counter filled with a mixture of Ar + CH4 (10%) at 1 bar. We interpret the results as a possible photoelectric effect associated with hidden photons ... More
Spectral properties of correlation functions of fields with arbitrary position dependence in restricted geometries from the ballistic to the diffusive regimesAug 09 2011The transition between ballistic and diffusive motion poses difficult problems in several fields of physics. In this work we show how to calculate the spectra of the correlation functions between fields of arbitrary spatial dependence as seen by particles ... More
Self-compensation in manganese-doped ferromagnetic semiconductorsSep 13 2002We present a theory of interstitial Mn in Mn-doped ferromagnetic semiconductors. Using density-functional theory, we show that under the non-equilibrium conditions of growth, interstitial Mn is easily formed near the surface by a simple low-energy adsorption ... More
Magnetism in Closed-shell Quantum Dots: Emergence of Magnetic BipolaronsJun 12 2011Similar to atoms and nuclei, semiconductor quantum dots exhibit formation of shells. Predictions of magnetic behavior of the dots are often based on the shell occupancies. Thus, closed-shell quantum dots are assumed to be inherently nonmagnetic. Here, ... More
Results from a Hidden Photon Dark Matter Search Using a Multi-Cathode CounterJan 25 2019The results of measurements are presented as rates of single electrons emitted from a cathode of a proportional counter filled with an argon--methane mixture. The results are interpreted as a possible photoelectric effect associated to hidden photons ... More
Energy Level Lifetimes in the Single-Molecule Magnet Fe_8 : Experiments and SimulationsDec 06 2007We present pump-probe measurements on the single-molecule magnet Fe_8 with microwave pulses having a length of several nanoseconds. The microwave radiation in the experiments is located in the frequency range between 104 GHz and 118 GHz. The dynamics ... More
Search for a new short-range spin-dependent force with polarized Helium 3Jan 30 2015Feb 02 2015Measuring the depolarization rate of a $^3$He hyperpolarized gas is a sensitive method to probe hypothetical short-range spin-dependent forces. A dedicated experiment is being set up at the Institute Laue Langevin in Grenoble to improve the sensitivity. ... More
Scaling Behavior of the Longitudinal and Transverse Transport in Quasi One-Dimensional Organic ConductorsSep 13 2004We report on dc and microwave experiments of the low-dimensional organic conductors (TMTSF)$_2$PF$_6$ and (TMTSF)$_2$ClO$_4$ along the $a$, $b^{\prime}$, and $c^*$ directions. In the normal state of (TMTSF)$_2$PF$_6$ below T=70 K, the dc resistivity follows ... More
Pump-Probe Experiments on the Single-Molecule Magnet Fe8 : Measurement of Excited Level LifetimesAug 22 2007We present magnetization measurements on the single molecule magnet Fe8 in the presence of pulsed microwave radiation. A pump-probe technique is used with two microwave pulses with frequencies of 107 GHz and 118 GHz and pulse lengths of several nanoseconds ... More
Random walks with thermalizing collisions in bounded regions; physical applications valid from the ballistic to diffusive regimesMar 24 2016Mar 30 2016The behavior of a spin undergoing Larmor precession in the presence of fluctuating fields is of interest to workers in many fields. The fluctuating fields cause frequency shifts and relaxation which are related to their power spectrum, which can be determined ... More
Constraining short-range spin-dependent forces with polarized $^3$HeNov 22 2015We have searched for a short-range spin-dependent interaction using the spin relaxation of hyperpolarized $^3$He. Such a new interaction would be mediated by a hypothetical light scalar boson with \CP-violating couplings to the neutron. The walls of the ... More
Lithium Experiment on Solar Neutrinos to Weight the CNO CycleOct 14 2003Jan 20 2004The measurement of the flux of beryllium neutrinos with the accuracy of about 10% and CNO neutrinos with the accuracy 30% will enable to find the flux of pp-neutrinos in the source with the accuracy better than 1% using the luminosity constraint. The ... More
New results of the extreme multiplicity studiesNov 30 2009Extreme multiplicity studies at 50 GeV in pp interactions are discussed. Preliminary multiplicity distributions at U-70 (IHEP, Protvino) energy have been obtained for more than 20 charged particles. A new elaborated algorithm for the track reconstruction ... More
Electron Spin Polarization in Resonant Interband Tunneling DevicesNov 14 2002We study spin-dependent interband resonant tunneling in double-barrier InAs/AlSb/ GaMnSb heterostructures. We demonstrate that these structures can be used as spin filters utilizing spin-selective tunneling of electrons through the light-hole resonant ... More
A Lithium Experiment in the Program of Solar Neutrino ResearchJan 12 2006The experiments sensitive to pp-neutrinos from the Sun are very perspective for the precise measurement of a mixing angle $\theta_{12}$. A $\nu $e$^{-}$ scattering experiment (Xmass) and/or a charged-current experiment (the indium detector) can measure ... More
Spin ordering in magnetic quantum dots: From core-halo to Wigner moleculesOct 24 2012Dec 14 2012The interplay of confinement and Coulomb interactions in quantum dots can lead to strongly correlated phases differing qualitatively from the Fermi liquid behavior. We explore how the presence of magnetic impurities in quantum dots can provide additional ... More
Complete spin extraction from semiconductors near ferromagnet-semiconductor interfacesJun 24 2005We show that spin polarization of electrons in nonmagnetic semiconductors near specially tailored ferromagnet-semiconductor junctions can achieve 100%. This effect is realized even at moderate spin injection coefficients of the contact when these coefficients ... More
Quantum computing on long-lived donor states of Li in SiJul 27 2004Nov 23 2004We predict a gigantically long lifetime of the first excited state of an interstitial lithium donor in silicon. The nature of this effect roots in the anomalous level structure of the {\em 1s} Li manifold under external stress. Namely, the coupling between ... More
Frequency shifts and relaxation rates for spin 1/2 particles moving in electromagnetic fieldsSep 15 2015Nov 21 2015We discuss the behaviour of the Larmor frequency shift and the longitudinal relaxation rate due to non-uniform electromagnetic fields on an assembly of spin 1/2 particles, in adiabatic and nonadiabatic regimes. We also show some general relations between ... More
Variable-Range Hopping of Spin Polarons: Magnetoresistance in a Modified Mott RegimeNov 14 2002We analize electrical conductivity controlled by hopping of bound spin polarons in disordered solids with wide distributions of electron energies and polaron shifts (barriers). By means of percolation theory and Monte Carlo simulations we have shown that ... More
Spin-dependent resonant tunneling through semimetallic ErAs quantum wellsAug 02 1995Resonant tunneling through semimetallic ErAs quantum wells embedded in GaAs structures with AlAs barriers was recently found to exhibit an intriguing behavior in magnetic fields which is explained in terms of tunneling selection rules and the spin-polarized ... More
Looking for Hidden Photon's Cold Dark Matter By Multi-Cathode CounterApr 03 2018Apr 09 2018The dark rate of single-electrons emitted from a cathode of a multi-cathode counter may be interpreted as the effect from Hidden Photons (HPs) of Cold Dark Matter (CDM). As a tentative approach the measurements have been performed at different temperatures ... More
Experience of Using a Multi-Cathode Counter (MCC) in a Search for Hidden Photon CDMDec 15 2015We report on a new technique of a Multi-Cathode Counter (MCC) developed to search for hidden photon (HP) cold dark matter (CDM) with a mass from 5 to 500 eV. The method suggested in the assumption that hidden photons of the mass greater than a work function ... More
Comment on "Pressure dependence of wall relaxation in polarized He^3 gaseous cells." by W. Zheng, H. Gao, Q. Ye, and Y.ZhangOct 28 2011The authors have demonstrated a strong linear pressure dependence of the longitudinal relaxation time for He^3 at room and cryogenic temperatures in a given experimental setup. They offer a theoretical explanation of the effect based on diffusion theory ... More
Electronic Control and Readout of Qubit States in Solid State Quantum Computing SystemsJan 16 2006Jan 25 2006We demonstrate that an $n^+/i/n^+$ junction is the most suitable candidate for electronic control and readout of qubit states in quantum computing systems based on shallow impurities. The signature of this system is that the $n^+-$regions serve as metallic ... More
The Study of a Temperature Dependence of the Dark Rate of Single Electrons Emitted from a Cathode of a Multi-Cathode Counter as a Method to Search for Hidden Photons of CDMAug 22 2016The dark rate of single electrons emitted from a metal cathode of the counter depends upon a temperature. At cryogenic temperatures the dark rate measured with bi-alkaline cathodes of PMT has been found to increase by lowering the temperature of the detector. ... More
On a Search for Hidden Photon CDM by a Multi-Cathode CounterMar 29 2016Jun 09 2016We report on a new technique of a Multi-Cathode Counter (MCC) developed to search for hidden photon (HP) cold dark matter (CDM) with a mass from 5 to 500 eV. The method is suggested in the assumption that HP-photon mixing causes emission of single electrons ... More
Thermodynamics of carrier-mediated magnetism in semiconductorsMay 30 2007We propose a model of carrier-mediated ferromagnetism in semiconductors that accounts for the temperature dependence of the carriers. The model permits analysis of the thermodynamic stability of competing magnetic states, opening the door to the construction ... More
Complete spin polarization of electrons in semiconductor layers and quantum dotsJun 24 2005We demonstrate that non-equilibrium electrons in thin nonmagnetic semiconductor layers or quantum dots can be fully spin polarized by means of simultaneous electrical spin injection and extraction. The complete spin polarization is achieved if the thin ... More
Complete spin polarization of degenerate electrons in semiconductors near ferromagnetic contactsSep 22 2006We show that spin polarization of electron density in nonmagnetic degenerate semiconductors can achieve 100%. This effect is realized in ferromagnet-semiconductor $FM-n^{+}$-$n$ junctions even at moderate spin selectivity of the $FM-n^{+}$ contact when ... More
Work of a multi-cathode counter in a single electron counting modeFeb 21 2018Feb 24 2018We describe a work of a multi-cathode counter of the developed design in a single electron counting mode with a cathode made of aluminum alloy. The results of the calibration of the counter are presented. The coefficient of gas amplification was found ... More
Using a Multi-Cathode Counter (MCC) in the Search for Hidden Photon CDMSep 10 2015We report on a new technique of a Multi-Cathode Counter (MCC) developed to search for hidden photon (HP) cold dark matter (CDM) with a mass from 5 to 10 eV. The method suggested in the assumption that hidden photons of the mass greater than a work function ... More
Study of the neutron quantum states in the gravity fieldFeb 08 2005Feb 14 2005We have studied neutron quantum states in the potential well formed by the earth's gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in the two lowest quantum states correspond to expectations ... More
A geometric approach to (g, k)-modules of finite typeMay 25 2011Let $g$ be a semisimple Lie algebra over $\mathbb C$ and $k$ be a reductive in $g$ subalgebra. We say that a simple $g$-module $M$ is a $(g; k)$-module if as a $k$-module $M$ is a direct sum of finite-dimensional $k$-modules. We say that a simple $(g; ... More
Zigzag algebras and finite-dimensional representations of minimal nilpotent W-algebrasOct 11 2016Let $\frak g$ be a simple finite-dimensional Lie algebra over an algebraically closed field $\mathbb F$ of characteristic 0. We denote by $\operatorname{U}(\frak g)$ the universal enveloping algebra of $\frak g$. To any nilpotent element $e\in \frak g$ ... More
Geometric Description of Epimorphic SubgroupsJul 08 2010Oct 30 2010Let $G$ be an affine algebraic group over an algrebraically closed field $\mathbb K$ of characteristic 0 and $H$ be a subgroup of $G$. The stabilizer of all the set of all vector-functions of $\mathbb K[G]^H$ with respect to the right action of $H$ is ... More
Bounded reductive subalgebras of sl(n)Jul 08 2010Mar 15 2011Let $\mathfrak g$ be a semisimple Lie algebra and $\mathfrak k\subset\mathfrak g$ be a reductive in $\mathfrak g$ subalgebra. A $(\mathfrak g, \mathfrak k)$-module is a $\mathfrak g$-module which after restriction to $\mathfrak k$ becomes a direct sum ... More
On Gelfand-Kirillov conjecture for some W-algebrasSep 21 2015Consider the W-algebra $W$ attached to the smallest nilpotent orbit in a simple Lie algebra $\frak g$ over an algebraically closed field of characteristic 0. We show that if an analogue of the Gelfand-Kirillov conjecture holds for such a W-algebra then ... More
Finite-dimensional representations of minimal nilpotent W-algebras and zigzag algebrasOct 11 2016Dec 24 2016Let $\frak g$ be a simple finite-dimensional Lie algebra over an algebraically closed field $\mathbb F$ of characteristic 0. We denote by $\operatorname{U}(\frak g)$ the universal enveloping algebra of $\frak g$. To any nilpotent element $e\in \frak g$ ... More
Evidence for the S=9 excited state in Mn12-bromoacetate measured by electron paramagnetic resonanceMar 17 2004We present high-frequency high-field electron paramagnetic resonance (EPR) measurements on the dodecanuclear manganese complex Mn12-bromoacetate (Mn12-BrAc). The crystal-field parameters are found to be identical to those of the original compound Mn12-acetate ... More
Anisotropy and Field-Dependence of the Spin-Density-Wave Dynamics in the Quasi One-Dimensional Conductor (TMTSF)_2PF_6Dec 08 2004The anisotropic and non-linear transport properties of the quasi one-dimensional organic conductor (TMTSF)_2PF_6 have been studied by dc, radiofrequency, and microwave methods. Microwave experiments along all three axes reveal that collective transport, ... More
The Nature of Heavy Quasiparticles in Magnetically Ordered Heavy FermionsJan 11 2002The optical conductivity of the heavy fermions UPd2Al3 and UPt3 has been measured in the frequency range from 10 GHz to 1.2 THz (0.04 meV to 5 meV) at temperatures 1 K < T < 300 K. In both compounds a well pronounced pseudogap of less than a meV develops ... More
(Meta-)stable reconstructions of the diamond(111) surface: interplay between diamond- and graphite-like bondingJan 27 2000Mar 18 2000Off-lattice Grand Canonical Monte Carlo simulations of the clean diamond (111) surface, based on the effective many-body Brenner potential, yield the $(2\times1)$ Pandey reconstruction in agreement with \emph{ab-initio} calculations and predict the existence ... More
Gaseous Detector with sub keV Threshold to Study Neutrino Scattering at Low Recoil EnergiesSep 17 2014Gaseous detector with a sub keV electron equivalent threshold is a very perspective tool for the precision measurement of the neutrino magnetic moment and to observe coherent scattering of neutrinos on nuclei. The progress in the development of low noise ... More
Size-independence of statistics for boundary collisions of random walks and its implications for spin-polarized gasesDec 20 2011Oct 24 2012A bounded random walk exhibits strong correlations between collisions with a boundary. For an one-dimensional walk, we obtain the full statistical distribution of the number of such collisions in a time t. In the large t limit, the fluctuations in the ... More
Correlated metals and the LDA+U methodJun 27 2002Dec 17 2002While LDA+U method is well established for strongly correlated materials with well localized orbitals, its application to weakly correlated metals is questionable. By extending the LDA Stoner approach onto LDA+U, we show that LDA+U enhances the Stoner ... More
Large Gaseous Detector of Ionizing Eradiation in Search for Coherent Neutrino-Nucleus ScatteringNov 26 2013Nov 28 2013We propose to search for coherent neutrino-nucleus scattering (CNNS)by means of a triple-sectioned low background proportional counter. As a working medium we plan to use argon and xenon at about 1 MPa. We have shown using bench-scale assembly, that pulse-shape ... More
A Lithium-Beryllium Method for the Detection of Solar NeutrinosOct 20 2009A method for the detection of solar neutrino has been developed using the laboratory bench installations. The efficiency of the extraction of beryllium from lithium as high as 96.4{%} has been achieved, and it was shown that lithium losses during the ... More
Donor Spin Qubits in Ge-based Phononic CrystalsSep 22 2014We propose qubits based on shallow donor electron spins in germanium. Spin-orbit interaction for donor spins in germanium is in many orders of magnitude stronger than in silicon. In a uniform bulk material it leads to very short spin lifetimes. However ... More
Large Stark Effect for Li Donor Spins in SiOct 30 2012We study the effect of a static electric field on lithium donor spins in silicon. The anisotropy of the effective mass leads to the anisotropy of the quadratic Stark susceptibility, which we determined using the Dalgarno-Lewis exact summation method. ... More
Backflow Effect on Spin Diffusion Near Ferromagnet-Superconductor InterfaceJan 21 2019The behavior of spin propagation in metals in various measurement schemes is shown to be qualitatively different than a simple exponential decay - due to the backflow effect on spin diffusion in the presence of interfaces. To probe this effect we utilize ... More
Reentrant Formation of Magnetic Polarons in Quantum DotsOct 03 2012We propose a model of magnetic polaron formation in semiconductor quantum dots doped with magnetic ions. A wetting layer serves as a reservoir of photo-generated holes, which can be trapped by the adjacent quantum dots. For certain hole densities, the ... More
GRANIT project: a trap for gravitational quantum states of UCNAug 19 2007Previous studies of gravitationally bound states of ultracold neutrons showed the quantization of energy levels, and confirmed quantum mechanical predictions for the average size of the two lowest energy states wave functions. Improvements in position-like ... More
Hall resistivity correlations in disordered electron-doped Nd$_{2-x}$Ce$_x$CuO$_{4+δ}$ filmsNov 23 2016The resistivity tensor correlations $\rho_{xy}$($B$)$\sim$ $[\rho_{xx}(B)]^\beta$ for the mixed state magnetic field dependencies of the resistivity tensor of electron-doped Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$/SrTiO$_3$ single crystal films near the antiferromagnetic ... More
Metal-insulator transition and giant anisotropic magnetoresistance in ultra thin (Ga,Mn)AsJun 16 2008MBE-grown, 5 nm-thick annealed Ga0.95Mn0.05As films with Tc~90K demonstrate transition from metallic to insulating state below To~10K, where sheet resistances Rsh~h/e2 and both longitudinal Rxx and transverse Rxy components become comparable. Below metal-insulator ... More
Magnetic ordering in quantum dots: Open vs. closed shellsSep 16 2015In magnetically-doped quantum dots changing the carrier occupancy, from open to closed shells, leads to qualitatively different forms of carrier-mediated magnetic ordering. While it is common to study such nanoscale magnets within a mean field approximation, ... More
Magnetic anisotropies of quantum dotsFeb 14 2012Magnetic anisotropies in quantum dots (QDs) doped with magnetic ions are discussed in terms of two frameworks: anisotropic $g$-factors and magnetocrystalline anisotropy energy. It is shown that even a simple model of zinc-blende p-doped QDs displays a ... More
Chiral Symmetry and Electron Spin Relaxation of Lithium Donors in SiliconJul 24 2008We report theoretical and experimental studies of the longitudinal electron spin and orbital relaxation time of interstitial Li donors in $^{28}$Si. We predict that despite the near-degeneracy of the ground-state manifold the spin relaxation times are ... More
Primitive ideals of $\operatorname{U}(\frak{sl}(\infty))$Aug 31 2016We provide an explicit description of the primitive ideals of the enveloping algebra $\operatorname{U}(\frak{sl}(\infty))$ of the infinite-dimensional finitary Lie algebra $\frak{sl}(\infty)$ over an uncountable algebraically closed field of characteristic ... More
Support varieties of $(\frak g, \frak k)$-modules of finite typeJan 03 2011Let $\frak g$ be a reductive Lie algebra over an algebraically closed field of characteristic 0 and $\frak k$ be a reductive in $\frak g$-subalgebra. Let $M$ be a finitely generated (possibly, infinite-dimensional) $\frak g$-module. We say that $M$ is ... More
Affinity criterion for the quotient of an algebraic group by a one-dimensional subgroupSep 30 2007In this work we show that the homogeneous space of an affine algebraic group $G$ by a one-dimensional unipotent subgroup $H$ is affine if and only if the subgroup is not contained in any reductive subgroup of $G$.
Branching rules related to spherical actions on flag varietiesNov 27 2017Feb 06 2019Let $G$ be a connected semisimple algebraic group and let $H \subset G$ be a connected reductive subgroup. Given a flag variety $X$ of $G$, a result of Vinberg and Kimelfeld asserts that $H$ acts spherically on $X$ if and only if for every irreducible ... More
The Sensitivity of a Lithium Experiment on Solar Neutrinos to the Mixing Angle theta_{12}Aug 01 2003A lithium-based radiochemical detector is aimed primarily to detect neutrinos from CNO cycle what will provide a direct proof of its existence and will be a stringent test of the theory of stellar evolution. Another task which can be solved by this experiment ... More
Lithium Experiment in the Interplay of Solar and Neutrino PhysicsJun 17 2003In a future study of solar neutrinos a special emphasis should be given to the measurement of the fluxes of neutrinos generated in CNO cycle, because this is a direct way to measure with record uncertainty - less than 1% the contribution to the solar ... More
Seasonal Variations of the Effect from Solar Neutrinos in Lithium DetectorJan 08 2002Dec 02 2002The presence of two monochromatic lines of approximately equal intensity: $^{7}$Be- and pep-neutrinos in the sensitivity plot of lithium detector makes the pattern of the seasonal variations of the effect from solar neutrinos very characteristic in case ... More
On ideals in the enveloping algebra of a locally simple Lie algebraOct 01 2012We study (two-sided) ideals $I$ in the enveloping algebra $\U(\frak g_\infty)$ of an infinite-dimensional Lie algebra $\frak g_\infty$ obtained as the union (equivalently, direct limit) of an arbitrary chain of embeddings of simple finite-dimensional ... More
Primitive ideals of $\operatorname{U}(\frak{sl}(\infty))$Aug 31 2016Oct 23 2016We provide an explicit description of the primitive ideals of the enveloping algebra $\operatorname{U}(\frak{sl}(\infty))$ of the infinite-dimensional finitary Lie algebra $\frak{sl}(\infty)$ over an uncountable algebraically closed field of characteristic ... More
Fast greedy algorithm for subspace clustering from corrupted and incomplete dataJun 07 2013We describe the Fast Greedy Sparse Subspace Clustering (FGSSC) algorithm providing an efficient method for clustering data belonging to a few low-dimensional linear or affine subspaces. The main difference of our algorithm from predecessors is its ability ... More
Greedy Approach for Low-Rank Matrix RecoveryApr 15 2013We describe the Simple Greedy Matrix Completion Algorithm providing an efficient method for restoration of low-rank matrices from incomplete corrupted entries. We provide numerical evidences that, even in the simplest implementation, the greedy approach ... More
Correlation gap in the heavy-fermion antiferromagnet UPd_2Al_3Mar 14 2002Mar 21 2002The optical properties of the heavy-fermion compound UPd$_2$Al$_3$ have been measured in the frequency range from 0.04 meV to 5 meV (0.3 to 40 cm$^{-1}$) at temperatures $2 {\rm K}<T< 300$ K. Below the coherence temperature $T^*\approx 50$ K, the hybridization ... More
A Lithium Experiment as the Stringent Test of the Theory of Stellar EvolutionJan 04 2003Jan 20 2003We show that a lithium experiment has a potential to confirm or reject the value 1.5% of the solar luminosity attributed to a CNO-cycle by the SSM and to prove that the difference between total energy release of the Sun and what is produced in a hydrogen ... More
Spherical actions on isotropic flag varieties and related branching rulesDec 03 2018Let $G$ be a symplectic or special orthogonal group, let $H$ be a connected reductive subgroup of $G$, and let $X$ be a flag variety of $G$. We classify all triples $(G,H,X)$ such that the natural action of $H$ on $X$ is spherical. For each of these triples, ... More
Greedy Approach for Subspace Clustering from Corrupted and Incomplete DataApr 15 2013We describe the Greedy Sparse Subspace Clustering (GSSC) algorithm providing an efficient method for clustering data belonging to a few low-dimensional linear or affine subspaces from incomplete corrupted and noisy data. We provide numerical evidences ... More
Spherical actions on flag varietiesJan 08 2014Sep 22 2014For every finite-dimensional vector space V and every V-flag variety X we list all connected reductive subgroups in GL(V) acting spherically on X.
Spherical actions on isotropic flag varieties and related branching rulesDec 03 2018Feb 18 2019Let $G$ be a symplectic or special orthogonal group, let $H$ be a connected reductive subgroup of $G$, and let $X$ be a flag variety of $G$. We classify all triples $(G,H,X)$ such that the natural action of $H$ on $X$ is spherical. For each of these triples, ... More
The pseudomorphic to bulk fcc phase transition of thin Ni films on Pd(100)Jan 13 2004We have measured the transformation of pseudomorphic Ni films on Pd(100) into their bulk fcc phase as a function of the film thickness. We made use of x-ray diffraction and x-ray induced photoemission to study the evolution of the Ni film and its interface ... More