The study of low-dimensional electron systems in nanostructures, quantum dots, quantum wires and clusters is now one of the hottest fields of physics. On the one hand it is connected with the considerable promise of these systems for the use as elements of a new generation of micro- and nanoelectronic devices. On the other hand this field is very interesting for the basic science. For example, for an explanation of the Integer and Fractional Quantum Hall effect the standard methods of the many-particle theory had failed and therefore the introduction of new topological occurred to be were necessary. In 2D systems in magnetic fields not only the hierarchy of the incompressible quantum liquids connected with the quasiparticles with the fractional electric charge but also compressible phases of the composite fermions and phases that connected with the quantum crystallization of electrons were discovered. It is these regions of physics the Laboratory of nanostructure spectroscopy deals with. The head of the Laboratory is Prof. Yurii E.Lozovik. The Laboratory includes two scientific Groups (theory and computer simulation Group, the leader is Yu.E.Lozovik; experimental Group, the leader is senior scientific researcher S.P.Merkulova). The main fields of research in the Laboratory are theory computer simulations and experimental studies of nanostructures that are a base of future nanoelectronics and nanooptics. The basic theoretical problems such as the superfluidity of excitons, composite fermions, quantum clusters and crystals, quantum mechanics of particles with fractional statistics, quantum electrodynamical processes in optical microcavities etc. are also studied in the Laboratory.
Among the fields of investigations are also nanoptics, nanotechnology, photonic crystals spectroscopy of nanostructures, physics of ultrafast processes initiated by ultrashort laser pulses, physics of clusters and new cluster materials, nanomechanics and mesoscopic physics.
The general principle of the laboratory is the combination of analytical calculations based on modern possibilities of mathematical technique with computer simulations by molecular dynamics, quantum molecular dynamics, Monte-Carlo, part integral and diffusion quantum Monte-Carlo techniques . Ab initio simulation is used for study of complex systems in the cases where analytical calculations are impossible due to the the absence of small parameter. Computer simulations that are free, unlike physical experiments, from the influence of unimportant details, are exploited for verification of theoretical models and in search for optimum parameters for physical experiments on apertureless near field optics and nanotechnology in the Group of S.P.Merkulova. Our activity resulted in more than 400 published scientific works (including a number of reviews and collective monographs), and more than 30 Ph.D. theses (supervisor is Yu.E.Lozovik).
Some projects of the Lab were performed in the cooperation with the Laboratory of Spectroscopy of Ultrafast Processes and other laboratories of the Institute, Physical Department of Moscow State University (MGU), Institute of General Physics RAS , as well as with Technical University of Berlin, University of Goeteborg and Berkley University .
Nanooptics and Nanolithography
The plasmon surface optics with the femtosecond temporal resolution was proposed and experimentally realized in the Laboratory (in cooperation with MGU). The possibility to increase the signal of the surface plasmon was demonstrated. The proposed method was used for direct measurement of surface plasmon damping. Second harmonic at the interaction between femtosecond laser pulse and metal surface with periodic relief at conditions of ‘plasmon resonance' was studied. The noncollinear interaction between two surface plasmons was investigated for one-beam and two-beam regimes. The visualization of the surface plasmons by acoustic microscope was studied.
A new method of optical measurements which incorporates high temporal and spatial resolution was proposed in the Laboratory. This method uses the local enhancement of the light intensity in the vicinity of the tip of a scanning probe microscope, excited by a laser pulse. This enhancement is due to the “lighting rod” effect and excitation of local plasma resonances in the tip-substrate system. Eigenfrequencies and spatial distributions of optical fields near the tip were analyzed in detail. A new method of ultrahigh laser writing (λ/40 where λ is wavelength ), using the strong near field (see above), has been realized on different materials. Namely, the formation of the surface nanostructures at the nanolocal influence of femtosecond laser pulse were observed. The strong near field can be used also for investigations of linear and nonlinear optical properties of nanostructures with the sub wavelength (nanometer) spatial resolution.
Fig.1. Nanolithography: cross-like structure with line width < 10 3 Å, created by apertureless near field method (see [57] and references therein).
Other activities:
· The cavitational processes and self-organization under the laser action on material were also studied.
· The spectra of plasmons localized near the impurities and in different inhomogeneous systems were analyzed.
· The Raman scattering on the localized plasmons and the damping of these plasmons were calculated.
· The supertransmission of the metal film with nanoholes due to the local plasmons excitation was analyzed.
· The properties of photon crystals with metal elements were studied in detail. The anomalous suppression of the electromagnetic waves scattering from the system of particles with the magnetic covering (nonreflecting covering) was predicted. The theory of the scanned capacitive microscopy was developed.
· Light backscattering in disordered 2D media due to weak localization phenomena was studied.
Quantum electrodynamics of microcavity. Femtosecond spectroscopy of microcavity.
The control Lamb shift of an atom in a cavity was considered. The new effect, namely, photonless excitation of an atom in the nonstationary microcavity due to nonadiabatic modulation of Lamb shift by nonstationary zero-point oscillations of electromagnetic field we called this effect as -the dynamical Lamb effect- was predicted. The nonstationary Casimir effect, that is the generation of photons in a vacuum at the instant shift of the neutral walls was quantitatively calculated for the first time. The statistical properties of the irradiation in dynamical Casimir effect, their angular distribution and intensity were calculated. The realistic experimental scheme was proposed for the observation of the photon generation based on the use of the femtosecond laser pulses generating in femtosecond time scale electron-hole plasma in initially transparent semiconductor film, that plays the role of ‘instantly' arising cavity wall. The nature of the experimentally observed ultrafast switching of the microcavity modes in the system semiconductor film – metal was analyzed.
Optics of ultrafast processes in solids.
The understanding of basic processes in nanostructures in a femtosecond temporal scale is important for the elaboration of a new class of ultrafast devices and principally new basic elements for nano- and optoelectronics, for the development of principles of coherent control of excitations (e.g. excitons), for coherent control of chemical reactions (femtochemistry ) and etc. Moreover the spectroscopy with ultrahigh temporal resolution gives the unique information about ultrafast relaxation in solids in ‘real time' and allows do select a relaxation of different groups of charge carriers. The new method for study of the Fermi-liquid properties of the electron subsystem in metals and superconductors was developed in the Laboratory. The method is based on the analysis of the spectral dependence of the ultrafast photoinduced response relaxation time studied by femtosecond pump – supercontinuum probe spectroscopy. The behavior of the spectral dependence of the ultrafast photoinduced response relaxation time was predicted for a set of conducting materials. The method is based on the experimental study of the electron relaxation rate near the Fermi surface by pump-supercontinuum probe spectroscopy.
The relaxation time dramatically increases for optical transitions near the Fermi surface that gives the possibility for the direct determination of the Fermi level. The linear dependence of the electron relaxation rate observed for the underdoped oxide superconductor YBCO demonstrates the nonFermi behavior of carriers connected with strong electron correlation effects. These studies the manifestation of new type of spectroscopy, spectroscopy of relaxation times.
The electromagnetic response of superconductors for any ratio between coherence length and London penetration depth have been calculated. The theory for transitions from the valence band to the conductivity band in superconductors have been developed. The behavior of superconducting gap in this transition was analyzed. This theory was confirmed by means of the femtosecond laser spectroscopy. The new method for study of electron-phonon interaction parameters on femtosecond laser spectroscopy was proposed and experimentally realized.
The photoinduced processes in Ñ 60 were investigated at the femtosecond temporal scale for the wide spectral region. The processes and mechanisms of the ultrafast energy relaxation of charge carriers were studied in details that is important for the possible use of fullerenes in optoelectronics. The new method for determination of mobility edge in disordered materials by femtosecond pump-supercontinuum probe spectroscopy was proposed and experimentally realized. The method is based on the determination of the spectral dependence of a stretched exponential relaxation in a wide probing spectral range. The studies in this region are carried out in the cooperation with Technical University of Berlin, University of Goeteborg , Berkley University , Moscow State University , Institute of Chemical Physics RAS , and the Lab. of Spectroscopy of Ultrafast Processes of Institute of Spectroscopy.
Optics and electronic properties of nanostructures
Two-component systems. The spectra of excitons and biexcitons in coupled quantum wells and their behavior in strong magnetic fields have been studied. The dispersion engineering of interwell excitons and luminescence control by parallel magnetic field were proposed and experimentally realized. This gives the possibility to determine experimentally the exciton dispersion law (with the help of fluorescence) and the dependence of the exciton mass on the magnetic field. It was shown that in strong magnetic fields, in accordance with the theory developed in the Laboratory, the magnetoexciton effective mass is determined by the relation between center of mass motion and the internal structure of exciton and this effective mass in high magnetic fields is much greater than sum of the electron and hole band masses. The instant transformation of exciton in weak magnetic field with the increase of the exciton momentum was studied.
The different phases of the system of indirect excitons and magnetoexcitons in coupled quantum wells have been considered, in particular, the properties of superfluid and crystal phases have been predicted. The magnetic characteristics and Josephson-type effects (in the nonsuperconducting system !) in coupled quantum wells with spatially separated electrons and holes have been analyzed in detail. It has been discovered that in a magnetic field smaller than some critical, CQWs behaves as weak diamagnetic. In fields greater than the critical one, the vortexes of this field penetrate into the space between wells. These works and previous works performed in the Laboratory have opened up the new physics of interwell exciton system in quantum wells. Now the very interesting experimental results were obtained in this field of physics (V.B.Timofeev et al.; L.V.Butov, D.Chemla; D.Snoke etc. ). Our studies in this field carry out in the cooperation with the Berkley University and Institute of Solid State Physics RAS .
The problem of the exciton absorption in the quasi-two-dimensional nonuniform systems in the strong transverse magnetic field H have been considered. The photoabsorption for the random fields in single and coupled quantum wells was calculated. In the strong magnetic fields the absorption factor decreases as H increases in agreement with the experiment. The transport times and free path lengths for the magnetoexcitons in quantum wells have been calculated. The similar calculations have been performed also for the spatially direct and indirect magnetoexcitons in coupled quantum wells in the random field.
The weak localization of the direct and indirect excitons and magnetoexcitons in a the random potential have been studied for the first time.
The influence of the disorder on quasi-two-dimensional Bose-condensation and superfluidity of the exciton was considered. It is interesting that they are suppressed in different rates (so the possibility of the existence of superfluid without base-condensate is not excluded in the disordered exciton system!). The weak localization of Wannier-Mott excitons and plasmons in the disordered semiconductors was considered.
The dissociation and change of the ground state of the biexciton induced by magnetic field is predicted.
The theory for the two-dimensional (monolayer) electron-hole systems in the strong magnetic fields was developed. In the framework of the theory the detailed diagram analysis of the many-particle system with macroscopical degeneration was performed for the first time. The theory gives the unexpected (at first view!) result that due to the symmetry of the interaction the magnetoexciton system in the strong magnetic field limit at any Landau level filling is the Bose-condensate ideal gas of magnetic excitons. This result was demonstrated in the framework of two approaches, the mentioned diagram analysis and by operator algebra (that is new exact solution of many-particle quantum problem was obtained!). These works were confirmed later by set of theoretical and experimental studies. The spectrum, phase diagram, and thermodynamical properties of the system were studied in detail in strong and intermediate magnetic fields.
The theory of 2D electron-hole systems with spatially-separated electrons and holes in strong magnetic fields was developed. In particular in a small density system the problem can be reduced to a system of rarefied bosons in the absence of magnetic field but with masses and interactions depending on the field. A quantum phase transition gas-liquid has been investigated in the interwell exciton system with growth interlayer separation of D. The temperature of Kosterlitz-Thouless transition to the superfluid as function of D was calculated. The quantum Mott transition metal-dielectric has been considered for anisotropic electron-hole system in coupled quantum wells. The instability of the ground state of the system of interacting indirect excitons on a film of superlattice with intermitting layers of electrons and holes has been revealed. The stable system in the latter case occurs to be the system of indirect quasi-2D biexcitons consisting of indirect excitons with oppositely directed dipole momenta. The radius and energy of indirect exciton coupling we are calculated. The spectrum of collective modes of rarefied system of quasi-2D indirect biexcitons interacting as quadrupoles has been investigated. The density of superfluid component and the temperature of Kosterlitz-Thouless transition to the superfluid state have been analyzed in the system of indirect biexcitons.
The BCS-type instability of a bilayer system of composite fermions (at half Landau filling fraction) has been considered. The influence of composite fermion marginality (the absence of weakly damping excitations near the Fermi surface) on coupling has been analyzed.
The system of interacting spatially-separated excitons and electrons, particularly in the presence of Bose-condensate of excitons has been examined. The kinetic properties of the connected system with electron-exciton drag effects – the interaction of excitations in a subsystem of excitons and electrons have been studied. The expressions for linear response coefficients of the electron subsystem to the quantities magnitudes determining nonequlibrium state in the subsystem of excitons have been obtained. Experimental observation of these drag effects can give new information about the phase state of excitons on the electric response in the electron layer and, moreover, give a new way of control of excitons with the use of electrons transport.
An unusual Raman scattering and two-photon emission of Bose-condensed excitons, caused by simultaneous recombination (or creation) of two excitons with opposite momenta. These effects leaving unchanged the number of above-condensate excitons are possible only in the presence of exciton Bose-condensate in the system and thus can be used as a new method of its detection.
The possibility of coolling excitons by the coherent radiation in the regime of occupation trapping has been considered.
The phonon spectroscopy of a coherent phase of excitons has been studied. The possible control coherent phase of interwell excitons with the use of transverse electric and parallel magnetic fields has been analyzed.
Quantum and non-linear optics of coherent phase of excitons has been studied. The presence of angular correlation of photons due to coherent recombination of two or several excitons from Bose-condesate which can be studied in experiments of Hanbury Brown-Twiss type has been predicted. The induced backscattering from coherent phase of excitons and anomalous light propagation has been predicted (Fig. 2). A number of new many-photon effects have been predicted. The observation of these effects can serve as experimental criteria of exciton phase coherence.
The quantum magnetic field initiated crystallization of 2D system of electrons in semiconductors and image forces influence on it has been predicted and studied in detail in microscopic and phenomenological approaches.
Quantum Hall effect has been considered in drift approach. The connection between quantized Hall conductance and geometric topological invariant in the system has been revealed. The drift resonance in 2D system of electrons in strong magnetic fields connected with resonance excitation of drift boundary currents along external and internal boundaries of the system. The consistent microscopic theory of collective excitations in quantum dos and arrays of quantum dots in strong magnetic fields has been developed.
The dynamic response of the system in the quantum Hall effect regime has been studied and it has been shown that it represents the properties of fractal contours of random potential. The phenomena of drift resonance in that system on the example of Fermi equipotentials has been predicted. The microscopic theory of boundary magnetoplasmons, based on the generalized random-phase approximation was developed.
The theory of composite fermions with attached two flux quanta in anisotropic system with the half Landau level filling was developed. It has been shown that shape of the Fermi-contour of composite fermions is the same as in the 2D system of electrons in the absence of magnetic field, but the dispersion laws are completely different.
The equation of state of a rarefied anions (quasiparticles with fractional statistics) system has been derived.
The spin polarization of composite fermions has been investigated. The theory is in good agreement with experiment.
In the frame of conform-invariant theory the classification of quasiparticles and gapless excitations of the system in the regime of fractional Hall effect has been introduced. The possibility of existence of a new non-Abelian type of statistics of excitations has been pointed out.
Mesoscopic clusters. Quantum dots, “molecules” and “crystal” of quantum dots
In works of laboratory for the first time mesoscopic electronic crystals and strongly-correlated states of electrons in quantum dots were investigated. Coulomb mesoscopic clusters as computer simulations and analytical calculations show in quasi-classical regime have crystalline shell structure reminiscent of hypothetic 3D or 2D Thomson atom with corresponding Periodic Table. With growth of temperature and/or ground-state oscillations (for example, with density variations) phase transitions take place in clusters. It is interesting to note that in mesoscopic 2D and 3D cluster melting occurs in several stages: at first mutual orientational melting of adjacent “crystalline” shells occurs (one or more shells remaining “crystalline” start to rotate relative to one another). Then, at appreciably greater values of control parameters, disappearance of shell structure and disappearance of “crystalline” order inside shells, i.e. the transition to Fermi-liquid take place. (See Fig.3 for illustration of such a quantum melting). This scenario is connected with smallness of barrier of relative rotation of shells relative to the barrier for the jump of particles between neighbor shells in its turn caused by incommensurability of shells of mesoscopic clusters and corresponding compensation of interactions of adjacent shells.
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Fig.3 Quantum orientational melting and radial melting of mesoscopic electronic clusters. Evolution of distribution N=19 electrons with variation of steepness of confining potential (the transition from Wigner “crystal” to Wigner “molecule”). [40]
The influence of mesoscopic effects (the number of electrons in quantum dot) on the phase diagram of the system has beenstudied in detail.
Strong magnetic fields for large electronic clusters suppress the amplitude of ground-state oscillations and induce crystallization by the same way as for extended systems. But for small clusters another effect becomes essential – the growth of effective steepness of confining potential in strong magnetic fields, leading to the growth of equilibrium density of electrons. As a result the influence of magnetic field on the crystallization of the system of several electrons in quantum dots becomes non-monotonous. Analogous effects – shell structure, many-staged melting – has been discovered also for mesoscopic clusters of different nature – dipole; mesoscopic system of vortices in a superconducting island etc.
A topological classification of spherical clusters has been developed.
For calculations of quantum Coulomb clusters such methods as imaginary time method, variational method, and also some non-perturbative methods – expansion on dimensionless quantum parameter or reciprocal number of dimensions.
The reorganization of spectrum accompanying the variation of parameters of the system has been analyzed. The “molecules” of quantum dots, vertically and horizontally coupled quantum dots have been calculated , their spectra, the spontaneous magnetization– the spin reorganization with variation of structure parameters has been predicted.
Excitons and trions in quantum dots have been calculated.
The microscopic theory of low-lying collective excitations of quantum dots in strong magnetic fields, considering infinite subsequence of diagram of Coulomb interaction of the same order on small dimensionless parameter of the problem has been developed.
Superfluidity, Superconductivity and magnetism of mesoscopic particles and arrays of mesoscopic particles
· The system of mesoscopic traps with Bose-condensate of atoms (or excitons) was considered in detail. We proposed a new model describing the quantum fluctuations of the order parameter phases in the arrays of mesoscopic superfluid and superconducting structures, and their influence on the ordered state destruction. The model employs a consistent definition of the quantum mechanical ‘phase operator'. Developed theory allows studying the arrays of small traps, with very low average number of particles in a trap. In this case, the standard approach using the operators of phase and number of particles as conjugates, is not applicable. We discovered the essential difference between the phase diagrams of arrays of macroscopic and mesoscopic particles. Analogous results were obtained with the help of Bose-Hubbard model.
· The influence of weak localization of the quasiparticles in the disordered superconductor on its heat conductivity was studied.
· Transition into the superconducting state in layered systems was investigated.
· Anomalous dia- and paramagnetism of the mesoscopic particles was predicted. We have studied the properties of superconducting particles of nanometer size.
· We studied the formation and distribution of the nanometer size clusters in the dense media. The essential role of the Coulomb interaction in nanometer ballistic contacts and semiconductors was analyzed.
Nanomechanics. Nanotubes. New cluster materials
The recent progress in nanotechnology has enabled researchers to construct the nanomechanisms and nanoelectromechanical devices, in particular, using the nanotubes. In multi-walled carbon nanotubes, as the calculations show, energy barriers for the relative interlayer motion are low, and so one can use them as moving parts of nanomechanisms, that was experimentally realized recently. In this connection we proposed the classification of the multi-walled nanotubes' structures, calculated their potential relieves in detail, and analyzed the energy barriers for the relative motion. We studied the double-walled nanotubes with the potential relieves corresponding to screw-nut threading. Various types of motion were analyzed in microscopic approach. The new nanodevices with the motion of screw-nut type were proposed.
The mechanisms of formation of new carbon nanostructures (fullerenes, nanoparticles, nanotubes and cones) were analyzed in detail. Effect of mutual orientational melting of the shells in multi-shell carbon nanoparticle (‘onion') was predicted. Potential barriers for the relative shells rotation in the carbon nanoparticle were calculated. We estimated the temperature of orientational melting of the nanoparticle. In light of the possible application utilization of the fullerites in optoelectronics we studied in detail the ultrafast processes in these materials.
We have developed the microscopical theory of crystal oscillation spectra, that consistently takes into account all lattice anharmonicities of the same order in the small (up to the melting point) dimensionless parameter: the ratio of the mean squared atom's displacement from the lattice sites to its period (generalized Lindemann parameter ). Summation of the infinite set of the diagrams of the same order in mentioned parameter gives the closed system of equations for the oscillation frequencies. Numerical solution of this equation shows that the phonons soften with the increase of controlling parameter (temperature density of particles, etc.). The spectrum softening is linear in the beginning at the small temperature, then it is sharper, and, at last, at some value of the controlling parameter, the real solution for the frequency of transversal oscillations disappears. This is the manifestation of instability connected with the disappearance of the shear modulus (or transverse long wavelength phonons). Thus one can find the melting point from the first principles, for given potentials of interaction between the particles. The calculations are in good agreement with the physical and numerical experiments. In addition, we explained the universality of the Lindemann parameter and other values.
. Convincing evidence in favor of this theory (in addition to the adequate analysis of the skeleton diagrams in anharmonicities in the perturbation theory) is the very good agreement of the theory conclusion with the results of physical and numerical experiments for a set of two-dimensional crystals. Empirical melting criterion, particularly Lindemann criterium was generalized and proved for the two-dimensional systems (usual Lindemann criterion is of no use for two dimensions, because the mean squared displacement of a particle from the site diverges in thermodynamical limit ).
New methods for the phonon laser creation were studied. Weak localization of excitons, plasmons and quasiparticles with random masses in disordered system was investigated.
The phase transitions in a set of three-dimensional physical models, described by the XY-model, were studied. We described the phase transition spiral-ball for the vortices and discovered the connection between the fractal dimensionality of the essential topological excitations and critical exponents of the phase transitions.
In a wide region of magnetic fields we studied the spectra, oscillator forces and other characteristics of few and many-electron atoms, ions and molecules. The sharp change of structure of an atom moving in the strong magnetic field with the increase of its magnetic momentum was studied in detail. Velocity of an atom in the magnetic field is the non-monotonous function of its momentum. We have calculated the maximum possible transverse velocity of an atom in the given magnetic field. The atom mass dependence on the magnetic field was analyzed in detail. We also considered the paramagnetism of many electron atoms, and the molecular dissociation and reconstruction of the bond type in the ultrastrong magnetic fields.
By means of the expansion in the inverse space dimensionality we analytically calculated the approximate dependencies of three atom binding energy versus the interaction parameters, obtained the condition of the cluster formation from several particles and its spectrum, and determined with the high accuracy (up to ten signs!) the constants of the van der Waals interaction (including the non-adiabatic corrections).
The toroidal atomic moment, connected with the parity nonconservation, was predicted and calculated for the first time. The methods of its measurement were analyzed.
The Bose-condensation of atoms and strong-correlation Tonks regime in the quasi-one-dimensional traps was considered. The drag effects in two vertically coupled traps with Bose-condensed atoms were studied.
We developed new methods for the computer simulation of the quantum systems dynamics (Quantum Molecular Dynamics) based on the Wigner approach in the quantum mechanics and quantum tomography. The latter approach seems to be quite promising, because in its framework quantum mechanics is formulated through the introduction of the nonnegative function, in contrast to other approaches. This, in principle, allows to overcome the difficulties with the sign “problem” in Fermi-systems simulations.
By means of these methods we stimulated the tunneling of the wave packets, calculated the tunneling time, studied the influence of the interaction on the tunneling time, and also weak localization of electrons in disordered systems.
With the help of the Diffusion Monte Carlo we calculated the influence of the disorder on the Bose-condensation and the regime of strong correlation in the one-dimensional Bose system.
By means of the Path Integral Monte Carlo we investigated the coherent and strong-correlation states in a number of Fermi and Bose systems, particularly, in mesoscopic systems of electrons, atoms with induced dipoles or dipole excitons etc.
Using computer simulations we calculated the spectra, thermodynamic and structure properties, as well as the melting, of a set of infinite two-dimensional systems with Coulomb, dipole-dipole and van der Waals interactions.
By means of the computer simulations we investigated the nature of melting of the two-dimensional crystals and for the first time discovered the earlier predicted theoretically gexatic (liquid crystal) phase in two-dimensional electronic system. We also demonstrated that the melting of the electronic crystal indeed takes place in two stages. Anharmonic structure of the spectra of crystals were investigated using the computer simulation. Its results show that with the increase of temperature the softening of the transversal phonons and hardening of the longitudinal phonons take place.
The mesoscopic electronic crystals and strongly correlation electronic states in quantum dots were investigated for the first time.
The general analysis of the phase transitions in the two-dimensional systems was performed using the conform field theory. We developed in detail the non-perturbative (by the interparticle interactions) method for the calculation of the bound states in quantum systems, that employs the e -expansion near the space dimension d=2, as well as the 1/d-expansion, where d is the space dimensionality.
The equation of state for the quasiparticles with the fractional statistics (anyons) was analyzed.
The mechanism of quarks confinement, based on the stochastic behavior of the gluon fields and Anderson localization in the corresponding random static effective potential, was proposed.
1 Yu.E. Lozovik, A.V. Filinov, A.S. Arkhipov, Simulation of wave packet tunneling of interacting identical particles, Phys. Rev., E 67, No2, 026707 (2003).
2 Yu.E. Lozovik, S.Y. Volkov , Motion of a 3D exciton in a magnetic field: Exciton-magnetoexciton "phase" transition, J. Exp. Theor. Phys., 96, N3, 564-571 (2003).
3 Yu.E. Lozovik, A.V.Minogin, A.M.Popov, Nanomachines Based on Carbon Nanotubes, Phys. Lett. A 313, No1-2, 112 – 121(2003).
4 A.V.Filinov, M. Bonitz, and Yu.E. Lozovik, Excitonic clusters in coupled quantum dots, J. Phys. A: Math. Gen., 36, No.22, 5899-5904, (2003).
5 J.Bereiter-Hahn, C.Blase, Yu.E. Lozovik YE, et. al., Study of surface plasmons with a scanning acoustic microscope, Quantum Electronics., 33, No.5, 451-455 (2003).
6 A.S. Arkhipov, Yu.E. Lozovik, New method of quantum dynamics simulation based on the quantum tomography, Phys. Lett. A 319, No.3-4, 217-224 (2003). A.S. Arkhipov, Yu.E. Lozovik, Phys.Rev.A (in print).
7 P.Ludwig, A.V. Filinov, M. Bonitz, Yu.E. Lozovik, Ground state and structural transitions in mesoscopic electron hole bilayers, Contributions to plasma physics, 43, No.5-6, 285-289 (2003).
8 A.V. Klyuchnik, S.Y. Kurganov, Yu.E. Lozovik, Plasma optics of nanostructures , Phys. Sol. State , 45, No.7, 1327-1331 (2003).
9 A.V. Klyuchnik, S.Y. Kurganov, Yu.E. Lozovik, Plasmons at a hole in a screen, Phys. Sol. State , 45, No.9, 1793-1797 (2003).
10 Yu.E. Lozovik, V.D. Mur, N.B. Narozhnyi, 1/Q expansion for the energy spectrum of quantum dots, J. Exp. Theor. Phys., 96, No. 5, 932-939 (2003).
11 Yu.E. Lozovik, A.V. Minogin, A.M. Popov, Possible nanomachines: Nanotube walls as movable elements, JETP Lett., 77, No.11, 631-635 (2003).
12 Yu.E. Lozovik, I.L. Kurbakov, I.V. Ovchinnikov, Nonlinear optical phenomena in coherent phase of 2D exciton system, Sol. State . Comm., 126, No 5, 269-273 (2003).
13 Yu.E. Lozovik , A.M. Popov, A.V.Belikov, Classification of two-shell nanotubes with commensurate structures of shells, Phys. Sol. State, 45, No.7, 1396-1402 (2003).
14 N.B. Narozhny, A.M. Fedotov, Yu.E. Lozovik, Dynamical Casimir and Lamb effects and entangled photon states, Laser Phys, 13, No2, 298-304 (2003).
15 A.S. Arkhipov, Yu.E. Lozovik , V.I. Man'ko, Tomography for several particles with one random variable, Journal of Russian Laser Research, 24,No.3, 237-255 (2003).
16 Yu.E. Lozovik , V.A. Sharapov, Excitation of coherent acoustic phonons by a femtosecond pulse, Phys. Sol. State , 45, No.5, 969-971(2003).
17 Yu.E. Lozovik, S.Yu. Volkov, M. Willander, Crystallization and quantum melting of few electron system in a spherical quantum dot: quantum Monte Carlo simulation, Sol. State . Comm., 125, No2, 127-131(2003).
18 Livshits AM, Lozovik YE, Unwinding algorithm for numerical generation and writing of fullerenes, Phys. Sol. State , 45, No.7, 1403-1407 (2003).
19 Yu.E.Lozovik, I.V.Ovchinnikov, S.Yu.Volkov, L.V.Butov and D.S.Chemla, Quasi-two-dimensional excitons in finite magnetic fields, Phys.Rev.B 65, 235304 (2002).
20 Yu. E. Lozovik, O.L.Berman, M.Willander , Superfluidity of indirect excitons and biexcitons in coupled quantum wells and superlattices , J. Phys.: Condensed Matter, v.14, 12457-12475 (2002)
21 M.V.Demin, Yu.E.Lozovik, V.A.Sharapov, Drag effect of Bose –condensate in the system of two coupled traps, Pis'ma ZhETF 76, N3, 166-170 (2002).
22 P.A. Sundqvist, S.Yu.Volkov, Yu.E.Lozovik, M.Willander, Phase transitions of a few electron system in a spherical quantum dot, Phys.Rev. B 66, N7, 07 5335(2002).
23 Yu.E.Lozovik and I.V.Ovchinnikov, Many-photon coherence of Bose-condensed excitons: luminescence and related nonlinear optical phenomena, Phys.Rev.B66, 075124 (2002).
24 N.E. Kaputkina, Yu.E.Lozovik, Two-dimensional exciton with spatially-separated carriers in coupled quantum wells in external magnetic field, Physica E12, 323-326(2002).
25 Yu.E.Lozovik and I.V.Ovchinnikov, Stimulated multiphoton emission from exciton Bose-condensate, JETP Lett. 75, 10, 705 (2002).
26 D.V.Kulakovskii, S.I.Gubarev, Yu.E.Lozovik, Properties of the excitonic states in quantum wells GaAs/AlGaAs in the presence of quasi two-dimensional electron gas, JETP, 94 , N4, 785-793 (2002).
27 Yu.E.Lozovik, N.B. Narozhny, A.M.Fedotov, Dynamical Lamb effect versus dynamical Casimir effect, Proc. SPIE (2002).
28 Yu. E. Lozovik , V. A. Sharapov, Excitation of atom by image forces , Phys. Lett., A 293, N3-4, 191-194(2002).
29 Yu.E. Lozovik , A.L. Dobryakov, S.A. Kovalenko, S.P.Merkulova, S. Yu. Volkov, M.Willander, Study of Localization of Carriers in Disordered Semiconductors by Femtosecond Spectroscopy, Laser Physics , 12, N4, 802(2002).
30 M.Bonitz, V. Golubichniy, A.V.Filinov, Yu.E.Lozovik, Single-electron control of Wigner crystallization, Microelectronic Engineering 63, N1-3, 141-145(2002).
31 Yu.E. Lozovik, S.P. Merkulova, M.M. Nazarov, A.P. Shkurinov, and P.Masselin, Time resolved nonlinear surface plasmon optics, Pis'ma ZhETF, 75, N9, 551-554 (2002).
32 Y u.E.Lozovik, Controlling Bose-condensation of excitons and phonon laser, Uspekhi Fiz. Nauk 171, N12, 1373-1376(2001).
33 N.B.Narozhny, A.M.Fedotov and Yu.E.Lozovik, Dynamical Lamb effect versus dynamical Casimir effect, Phys. Rev. A.64, 053807 (2001).
34 Yu.E. Lozovik , I.V. Ovchinnikov, Light backscattering from exciton Bose-condensate, Pis'ma v ZhETF 74, 318-322 (2001).
35 A.L. Dobryakov, S.A. Kovalenko, Yu.E. Lozovik et al., Femtosecond spectroscopy of relaxation processes in metals and High-T-c superconductors , J. Exp. Theor. Phys., 92, N2, 267-276 (2001).
36 Yu.E. Lozovik , I.V. Ovchinnikov, Controlling spatially indirect exciton condensate in coupled quantum wells by external fields and phonon laser , Sol. St. Comm. , 118, N5, 251-255(2001).
37 Yu.E. Lozovik , S.P. Merkulova, I.V. Ovchinnikov, Sasers: resonant transitions in narrow-gap semiconductors and in exciton system in coupled quantum wells, Phys. Lett. A 282, N6, 407-414(2001).
38 Yu.E. Lozovik , I.V. Ovchinnikov I.V. , Cooling of excitons by coherent phonon radiation, JETP Lett, 73, N10, 524-528(2001).
39 D.V. Kulakovskii, S.I. Gubarev, Yu.E. Lozovik , Screening of exciton states by quasi-two-dimensional electron gas in quantum wells, JETP Lett., 74, N 2, 118-121 (2001).
40 L.V. Butov, C.W. Lai, D.S. Chemla, Yu.E. Lozovik, K.L. Campman, and A.C. Gossard, Observation of magnetically-induced effective mass enhancement of quasi 2D-excitons , Phys.Rev.Lett.87, No. 21, 216804 (2001).
41 A.V. Filinov, M. Bonitz, Yu.E. Lozovik , Wigner crystallization in mesoscopic 2D electron systems, Phys. Rev. Lett., 86, N17, 3851-3854(2001).
42 A.L.Dobryakov, S.A.Kovalenko, V.M.Farztdinov, S.P.Merkulova, N.P.Ernsting, Yu.E.Lozovik, Ultrafast relaxation in YBa2Cu307-δ on the femtosecond scale: Luttinger or two-dimensional Fermi liquid?", Sol.St.Comms.116, 439 (2000).
43 Yu.E.Lozovik, A.M.Popov, Orientational melting of two-shell nanoparticles: molecular dynamics study, Chem. Phys. Lett. 328, 355-362 (2000).
44 Yu.E.Lozovik, S.P.Merkulova, M.M.Nazarov, A.P.Shkurinov, From two-beam surface plasmon interaction to femtosecond surface optics and spectroscopy, Phys. Lett.A. A.276, N1-4, 127-132 (2000).
45 Yu.E.Lozovik, M.Willander, Excitons and magnetoexcitons in coupled quantum nanostructures: the role of a dirty environment, Appl. Phys., A 71, 379-390 (2000).
46 Yu.E.Lozovik, N.B.Narozhny, A.M.Fedotov, Excitation of atom in nonstationary cavity, Pis'ma v ZhETF 72, 344-349 (2000).
47 Yu.E.Lozovik, I.V. Ovchinnikov, Phonon laser and indirect exciton dispersion engeneering, Pis'ma v ZhETF 72, N 8, 617 (2000).
48 S.V.Lavrischev, S.P.Merkulova, A.L.Leonov, A.L.Merkulov, Yu.E.Lozovik, Electronic micromirror, Physica Scripta, 61, 187-191(2000).
49 D.B.Balagurov, A.V.Klyuchnik, Yu.E.Lozovik, Theory of scanning capacitance microscopy, Physics of Solid State, 42, N2, 371-376(2000); Transl. from: Fiz.Tverd.Tela, 42, N2, 361-366(2000).
50 S.A.Verzakov, Yu.E.Lozovik, Investigation of array of mesoscopic grains in the framework of quantum cosine model, Physics of Solid State, 42, N3, 409-414(2000); Transl. from Fiz.Tverd.Tela 42, N3, 400-406(2000).
51 A.L.Dobryakov, V.A.Karavinskii, S.A.Kovalenko, S.P.Merkulova, Yu.E.Lozovik, Observation of coherent phonon states in porous silicon fields, JETP Lett. 71, N7, 298-302 (2000) (Transl. from Pis'ma ZhETF 71, N7, 430-436 (2000)).
52 A.I.Belousov, Yu.E.Lozovik, Mesoscopic and macroscopic dipole clusters: structure and phase transitions, Eur. Phys. D 8, 251-264(2000).
53 D.B. Balagurov, Yu.E.Lozovik, Fermi surface of composite fermions and one-particle excitations at V=1/2: effect of band-mass anisotropy, Phys. Rev B 61, 1481-1484 (2000).
54 L.V.Butov, A.V.Mintsev, Yu.E.Lozovik, K.L.Campman, A.C.Gossard, From spatially indirect excitons to momentum - space indirect excitons by an in-plane magnetic field, Phys. Rev B 62, N3, 1548-1551(2000).
55 S.A. Kovalenko, A.L. Dobryakov, V.A.Karavanskii, D.V.Lisin, S.P.Merkulova, Yu.E. Lozovik, Femtosecond spectroscopy of porous silica, Physica Scripta 60, N6, 589-593(1999).
56 A.L.Dobryakov, V.M.Farztdinov, Yu.E. Lozovik, Linear electromagnetic responce of the nonlocal superconductor: explicit analytical results, Physica Scripta 60, (1999).
57 V.M.Farztdinov, A.L.Dobryakov, S.A. Kovalenko, D.V.Lisin, S.P.Merkulova, F.Pudonin, Yu.E. Lozovik, Ultrafast phenomena in copper films, Physica Scripta 60, N6, 579-584(1999).
58 A.L.Dobryakov, V.M.Farztdinov, Yu.E.Lozovik, G.Marowsky, Laser-induced nonequilibrium electron distribution in metals on a femtosecond time scale, Phys.Scripta, 60, N6, 572-579(1999).
59 S.P.Merkulova, A.L.Merkulov, S.V.Lavrishcev, Yu.E.Lozovik, Cavitation processes in solids induced by laser pulses, Physica Scripta 60, N6, 547-549(1999).
60 I.V.Kukushkin, K.von Klitzing, K.G.Levchenko, Yu.E.Lozovik, Temperature dependence of the spin polarization of composite fermion, JETP Lett. 70, N11, 722-726(1999).
61 E.A.Vinogradov, A.L.Dobryakov, V.M.Farztdinov, Yu.E.Lozovik, Yu.A.Matveets and S.A.Kovalenko, Femtosecond dynamics of semiconductor microcavity polaritons, Proceed. SPIE 3735, 105-112(1999).
62 Lozovik Yu.E., Merkulova S.P., The outlook for nanolocal femtosecond spectroscopy and nanolithography, Uspekhi Fiz.Nauk 169, N3, 348-350(1999). (transl.:Physics-Uspekhi 42, N3 (1999)).
63 Yu.E.Lozovik, D.V.Lisin, V.O.Kompanets, S.P.Merkulova, et.al., Femtosecond laser pulse nanolithography using STM tip, in "Fundamental Aspects of Laser-Matter Interaction", ed.K.N.Drobovich, Proc.SPIE, 3734, 424-431(1999).
64 Yu.E.Lozovik, S.A.Verzakov, M.Willander, Superfluidity of indirect excitons in a quantum dot, Phys.Lett.A 260 400-405(1999).
65 Yu.E.Lozovik, E.A.Rakoch, Characteristic features of the melting of two-dimensional mesoscopic Wigner clusters, Phys.Solid State 41, N8, 1373-1377(1999).
66 Yu.E. Lozovik, Lisin D.V., Ivanov A.I., Kompanets V.O., Yu.A.Matveets, Chekalin S.V., Merkulova S.P., Femtosecond laser pulse nanolithography using on STM tip, Laser Phys. 9, N2, 564-569(1999).
67 Lozovik Y.E., Klyuchnik A.V., Merkulova S.P., Nanolocal optical study and nanolithography using scanning probe microscope, Laser Phys. 9, N2, 552-556(1999).
68 Yu.E.Lozovik, Klyuchnik A.V., Balagurov D.B., Local capacitance spectroscopy, Phys.Scripta, 59, No.4, 319-322(1999).
69 Yu.E.Lozovik, M.M.Nazarov, A.P.Shkurinov, Effect of edge plasmon excitation at metal grating on the second harmonic generation of light, Physica Scripta 60 N1, 60-62(1999).
70 Yu.E.Lozovik, À .V.Filinov, Transmission time of wave packets through tunnelling barriers, JETP 88 N5, 1026-1035(1999).
71 G.E.Astrakharchik, A.I.Belousov, Yu.E.Lozovik, Properties of two-dimensional dusty plasma clusters, Phys.Lett.A 258, N2-3, 123-130(1999); G.E.Astrakharchik, A.I.Belousov, Yu.E.Lozovik, Two-dimensional mesoscopic dusty plasma clusters: structure and phase transitions, J. Exp. Theor. Phys, 89, No.4, 696-703 (1999).
72 Yu.E.Lozovik, M.V.Nikitkov, Kinetic properties of the spatially-separated excitons system and electrons with the Bose-exciton condensation, JETP, 116, N4 (10), 1440(1999).
73 Yu.E.Lozovik, E.A.Rakoch, Structure, melting and potential barriers in mesoscopic clusters of repulsing particles, J. Exp. Theor. Phys., 89, N6, 1089-1102 (1999).
74 Yu.E. Lozovik, O.L.Berman, M.Willander, Superfluidity of indirect biexcitons in superlattices, Europhys.Lett. 48 N3, 299-305(1999).
75 A.L.Dobryakov, Yu.E.Lozovik, The new optical method of the parameter measurement of electron-phonon interaction across the spectrum dependence of a relaxation rate, JETP Lett., 70, N5, 329-332(1999).
76 Yu.E.Lozovik, O.L.Berman, A.M.Ruvinskii, Superfluidity of "dirty" excitons, JETP Lett., 69, N8, 616-622(1999).
77 Lozovik Y.E., Berman O.L., Tsvetus V.G., Phase transitions of electron -hole and unbalanced electron systems in coupled quantum wells in high magnetic fields, Phys.Rev.B, 59, No.8, 5627-5636(1999).
78 Yu. E. Lozovik, A. V. Poushnov, Manifestation of exciton Bose condensation in induced two-phonon emission and Raman scattering, Phys.Rev. B 58, N10, 6608-6621(1998).
79 Yu.E.Lozovik, A.M.Ruvinsky, Transport of magnetoexcitons in single and coupled quantum wells, Physica Scripta 58, N1, 90-96(1998).
80 Yu.E.Lozovik, A.M.Ruvinsky, Magnetoexciton light absorption in inhomogeneous quasi- two- dimensional systems, JETP 87, N4, 788-795(1998).
81 Yu.E.Lozovik, O.L.Berman, The quantum crystallization of indirect excitons in coupled quantum wells, Physica Scripta 58, N1, 86-89(1998).
82 V.S.Filinov, S.Bonella, A.V.Filinov, Yu.E.Lozovik, Quantum molecular dynamics using Wigner representation, in: “Classical and Quantum Dynamics in Condensed Phase Simulations”, World Scientific Publishing, Singapore , 671-691(1998).
83 Yu.E.Lozovik, A.M. Popov, Theory, simulation and nanotechnological applications of adsorption on a surface with defects, Surface Science 414, N1-2 57-67(1998).
84 Yu.E.Lozovik, E.A.Rakoch, Energy barriers, structure and two stage melting of vortexes, Phys. Rev. B 57, N2, 1214-1225 (1998).
85 A.I.Belousov, Yu.E.Lozovik, Quantum orientational melting and the phase diagram of a mesoscopic system, JETP Lett. 68, N11, 858-863(1998).
86 A.I.Belousov, Yu.E.Lozovik, The new model system of mesoscopic Josephson junctions, JETP Lett. 66, N10, 649-654(1998).
87 A.I.Belousov, S.A.Verzakov, Yu.E.Lozovik, Josephson array of mesoscopic objects. Modulation of system properties through the chemical potential, JETP 114(2), 322-328(1998).
88 A.I.Belousov, S.A.Verzakov, Yu.E.Lozovik, Phase diagram of 2D array of mesoscopic granules, J. Phys. C 10, N5, 1079-1089(1998).
89 Yu.E.Lozovik, E.A.Rakoch, Coulomb clusters: melting and potential barriers, Phys.Lett.A 240, 311(1998).
90 Yu.E.Lozovik, A.V.Poushnov, Magnetism and Josephson effect in the coupled quantum well electron-hole system, Phys. Lett. A 228, 399-407(1997).
91 Zh.S.Gevorkyan, Yu.E.Lozovik, Light backscattering in a two-dimensional random system, Phys.Scripta 56, No.2, 208-211(1997).
92 Yu.E.Lozovik, O.L.Berman, V.G.Tsvetus, Superfluidity of indirect magnetoexcitons in coupled quantum wells, JETP Lett. 66, N 5, 332-337(1997).
93 Yu.E.Lozovik, O.L.Berman, Metal-insulator transition in a two-layered electron-hole system, Solid State Phys. 39, N9, 1476-1478(1997).
94 Yu.E.Lozovik, O.L.Berman, Phase transitions in the system of spatially separated electrons and holes, JETP 84, N 5, 1027-1035(1997).
95 N.K.Kultanov, Yu.E.Lozovik, The vortex-loop phase transition in the anisotropic 3D X-Y model, the role of screening and the polymer physics approach, Physica Scripta 56, N2, 129-136(1997).
96 V.M.Farztdinov, A.L.Dobryakov, V.S.Letokhov, S.A.Kovalenko, Yu.E.Lozovik, Yu.A.Matveets, N.P.Ernsting, Spectral dependence of femtosecond relaxation and coherent phonons excitation in C 60 films, Phys. Rev. B 56(7), 4176-4185(1997).
97 Yu.E.Lozovik, M.V.Nikitkov, Drag effects in a two-layer system of spatially separated electrons and excitons, JETP 84, No.3, 612-618(1997).
98 Yu.E. Lozovik, O.L.Berman, Phase transitions in the system of two coupled quantum wells, JETP Lett. 64, No.8, 573 (1996).
99 Yu.E.Lozovik, Clusters in confined potentials, Izvestiya RAN, Phys. 60, No.9, 85-91(1996).
100 N.K.Kultanov, Yu.E.Lozovik, The critical behavior of the 3D X-Y model and its relation with fractal properties of the vortex excitations, Phys.Lett.A 223, N3, 189-194 (1996).
101 Yu.E.Lozovik, Ion and electron clusters, Uspekhi Fiz.Nauk, 153, N2, 356-358(1987).
102 Yu.E.Lozovik, A.V.Klyuchnik, The dielectric function and collective oscillations in inhomogeneous systems, in: The Dielectric Function of Condensed Systems, edited by L.V.Keldysh, D.A.Kirzhnitz and A.A.Maradudin, Elsevier Science Publisher B.V., Chapter, 1987.
103 Yu.E. Lozovik, A.M. Popov, Formation and growth carbon nanostructures-fullerenes, nanoparticles, nanotubes and cones, Uspekhi Fiz.Nauk 61(9), 1711-1719(1997).
104 Yu.E.Lozovik, A.M.Ruvinskii, Magnetoexciton absorption in coupled quantum wells, JETP, 85, No.5 , 981-988(1997).
105 Yu.E.Lozovik, A.M.Popov, Formation of fulerenes, onions, and other nanometer size carbon clusters, in: Physics of Clusters, eds. G.N.Chuev,V.D.Lakhno, World Scientific Publishing, Singapore , 1-55(1998).
106 N.K.Kultanov, Yu.E.Lozovik, The critical behavior of the 3D X-Y model and its relation with fractal properties of the vortex excitations, Phys.Lett.A 223, N3, 189-194(1996).
107 Yu.E.Lozovik, S.P.Merkulova, A.L.Merkulov, Pulsed laser radiation used for multiple-spot welding, in: Laser Applications Engineering , Proc.SPIE, 3091, 13-15(1997).