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S. G. Matinyan

Publications and source records attributed to S. G. Matinyan.

18 recordsLinked to original sources
arXiv2015

Theory of Confined States of Positronium in Spherical and Circular Quantum Dots with Kane's Dispersion Law

Confined states of a positronium (Ps) in the spherical and circular quantum dots (QDs) are theoretically investigated in two size-quantization regimes: strong and weak. Two-band approximation of Kane dispersion law and parabolic dispersion law of charge carriers are considered. It is shown that the electronpositron pair instability is a consequence of dimensionality reduction, not of the size quantization (SQ). The binding energies for the Ps in circular and spherical QDs are calculated. The Ps formation dependence on the QD radius is studied.

cond-mat.mes-hall↗
arXiv2012

Electron tunneling in chaotic InAs/GaAs quantum ring

Two dimensional InAs/GaAs quantum ring (QR) is considered using the effective potential approach. The symmetry of QR shape is violated as it is in the well-known Bohigas annular billiard. We calculate energy spectrum and studied the spatial localization of a single electron in such QR. For weak violation of the QR shape symmetry, the spectrum is presented as a set of quasi-doublets. Tunneling between quasi-doublet states is studied by the dependence on energy of the states. The dependence is changed with variation of the QR geometry that is related to the eccentricity of the QR. An interpretation of the experimental result obtained in [1] is proposed. We show that the "chaos-assisted tunneling" effect found in this paper can be explained by inter-band interactions occurred by anti-crossing of the levels with different "radial" quantum numbers.

cond-mat.mes-hall↗
arXiv2012

Quantum Mechanics of Semiconductor Quantum Dots and Rings

We consider the several phenomena which are taking place in Quantum Dots (QD) and Quantum Rings (QR): The connection of the Quantum Chaos (QC) with the reflection symmetry of the QD, Disappearance of the QC in the tunnel coupled chaotic QD, electron localization and transition between Double Concentric QR in the transverse magnetic field, transition of electron from QR to the QD located in the center of QR. Basis of this consideration is the effective Schrödinger equation for the corresponding systems.

cond-mat.mes-hall↗
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↗
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↗
arXiv2006

The Partition Function in the Wigner-Kirkwood expansion

We study the semiclassical Wigner-Kirkwood (WK) expansion of the partition function $Z(t)$ for arbitrary even homogeneous potentials, starting from the Bloch equation. As is well known, the phase-space kernel of $Z$ satisfies the so-called Uhlenbeck-Beth equation, which depends on the gradients of the potential. We perform a chain of transformations to obtain novel forms of this equation that invite analogies with various physical phenomena and formalisms, such as diffusion processes, the Fokker-Planck equation, and supersymmetric quantum mechanics.

quant-ph↗
arXiv2003

Beyond Quantum Field Theory: Chaotic Lattices?

We review the idea of chaotic quantization, based on the dynamics of classical lattice gauge systems as well as on non-abelian plasma physics in the infrared limit. The basic conjecture between Planck constant and properties of the five dimensional classical theory (h=aT) is demonstrated numerically for the U(1) lattice gauge group.

hep-lat↗
arXiv2003

The Partition Function and Level Density for Yang-Mills-Higgs Quantum Mechanics

We calculate the partition function $Z(t)$ and the asymptotic integrated level density $N(E)$ for Yang-Mills-Higgs Quantum Mechanics for two and three dimensions ($n = 2, 3$). Due to the infinite volume of the phase space $Γ$ on energy shell for $n= 2$, it is not possible to disentangle completely the coupled oscillators ($x^2 y^2$-model) from the Higgs sector. The situation is different for $n = 3$ for which $Γ$ is finite. The transition from order to chaos in these systems is expressed by the corresponding transitions in $Z(t)$ and $N(E)$, analogous to the transitions in adjacent level spacing distribution from Poisson distribution to Wigner-Dyson distribution. We also discuss a related system with quartic coupled oscillators and two dimensional quartic free oscillators for which, contrary to YMHQM, both coupling constants are dimensionless.

hep-th↗
arXiv2003

Chaotic Quantization: Maybe the Lord plays dice, after all?

We argue that the quantized non-Abelian gauge theory can be obtained as the infrared limit of the corresponding classical gauge theory in a higher dimension. We show how the transformation from classical to quantum field theory emerges, and calculate Planck's constant from quantities defined in the underlying classical gauge theory.

hep-th↗
arXiv2001

Chaotic Quantization of Classical Gauge Fields

We argue that the quantized non-Abelian gauge theory can be obtained as the infrared limit of the corresponding classical gauge theory in a higher dimension. We show how the transformation from classical to quantum field theory emerges and calculate Planck's constant from quantities defined in the underlying classical gauge theory.

hep-th↗
arXiv2001

Quantum Dynamics from Classical Dissipative Systems

We argue that the quantized non-Abelian gauge theory can be obtained as the infrared limit of the corresponding classical gauge theory in a higher dimension. We show how the transformation from classical to quantum dynamics emerges and calculate Planck's constant from quantities defined in the underlying classical field theory.

hep-th↗
arXiv2000

Chaotic Quantization of Classical Gauge Fields

We argue that higher dimensional classical, nonabelian gauge theory may lead to a lower dimensional quantum field theory due to its inherent chaotic dynamics which acts like stohastic quantization. The dimensional reduction is based upon magnetic screening effects analagous to that in nonabelian plasmas.

hep-th↗
arXiv1998

Multiplicity Distribution and Mechanisms of the High-Energy Hadron Collisions

We discuss the multiplicity distribution for highest accessible energies of $pp$- and $\bar pp$- interactions from the point of view of the multiparton collisions. The inelastic cross sections for the single, $σ_1$, and multiple (double and, presumably, triple, $σ_{2+3}$) parton collisions are extracted from the analysis of the experimental data on the multiplicity distribution up to the Tevatron energies. It follows that $σ_1$ becomes energy independent while $σ_{2+3}$ increases with $\sqrt{s}$ for $\sqrt{s}\ge$ 200 GeV. The observed growth of $ $ with multiplicity is attributed to the increasing role of multiparton collisions for the high energy $\bar pp(pp)$- inelastic interactions.

hep-ph↗
arXiv1997

Classical Gluon Radiation in Ultrarelativistic Nuclear Collisions: Space-Time Structure, Instabilities, and Thermalization

We investigate the space-time structure of the classical gluon field produced in an ultrarelativistic collision between color charges. The classical solution which was computed previously in a perturbative approach is shown to become unstable on account of the non-Abelian self-interaction neglected in the perturbative solution scheme. The time scale for growth of the instabilities is found to be of the order of the distance between the colliding color charges. We argue that these instabilities will eventually lead to thermalization of gluons produced in an ultrarelativistic collision between heavy nuclei. The rate of thermalization is estimated to be of order $g^2 μ$, where $g$ is the strong coupling constant and $μ^2$ the transverse color charge density of an ultrarelativistic nucleus.

nucl-th↗
arXiv1995

Wave Packet Collisions in Yang-Mills-Higgs Theory

We present numerical simulations of colliding wave packets in spontaneously broken SU(2) Yang-Mills-Higgs theory. Compared with pure Yang-Mills theory, introducing the Higgs field leads to new aspects in the dynamics of the system. The evolution of the gauge field and the Higgs field is investigated as a function of the amplitude of the wave packets and of the mass ratio of the Higgs and the gauge boson. We find regions in our parameter space in which initial wave packets scatter into final configurations with dramatically different momentum distributions.

hep-ph↗
arXiv1995

Chaos Driven by Soft-Hard Mode Coupling in Thermal Yang-Mills Theory

We argue on a basis of a simple few mode model of SU(2) Yang-Mills theory that the color off-diagonal coupling of the soft plasmon to hard thermal excitations of the gauge field drives the collective plasma oscillations into chaotic motion despite the presence of the plasmon mass.

hep-ph↗
arXiv1993

Branching Processes and Multi-Particle Production

The general theory of the branching processes is used for establishing the relation between the parameters $k$ and $\bar n$ of the negative binomial distribution. This relation gives the possibility to describe the overall data on multiplicity distributions in $pp (p\bar p)$-collisions for energies up to 900 GeV and to make several interesting predictions for higher energies. This general approach is free from ambiguities associated with the extrapolation of the parameter $k$ to unity.

hep-ph↗