Grigor Alaverdyan

Yerevan State University | YSU · Chair of Applied electrodynamics end modeling

The properties of isospin-asymmetric cold nuclear matter are studied in terms of the relativistic mean-field theory in which, besides the fields of σ, ω, and ρ mesons, and the isovector, Lorentz-scalar field of the δ-meson is also taken into account. The properties of purely nucleonic np matter are studied as a function of the baryon density nB and...

In this textbook, the author presents lectures that he delivered to first-year students of the Radio Physics Faculty of Yerevan State University on kinematics, the first section of the general physics course "Mechanics". A short mathematical introduction provides the mathematical concepts and relationships needed to teach the course at the universi...

ISOSPIN-ASYMMETRIC COLD NUCLEAR MATTER IN THE RELATIVISTIC MEAN-FIELD MODEL WITH A SCALAR-ISOVECTOR INTERACTION CHANNEL Within the framework of the relativistic mean field theory, in which, in addition to the fields of σ,ω,ρ mesons, the isovector Lorentz scalar field of the δ meson is also taken into account, the properties of isospin-asymmetric c...

We are researching how compact stars are affected by the sudden shift in their properties caused by the quark deconfinement phase transition. The hadronic phase is explained using the relativistic mean-field theory, which includes a scalar-isovector 𝛿-meson effective field. To describe the quark phase, we use the MIT bag model, which considers the...

We investigate the thermodynamic properties of the hot β-equilibrated hadronic matter, which consists of neutrons(n), protons(p), electrons(e), electron neutrinos(ν_e), muons(μ), and muon neutrinos(ν_e). To describe such matter, we use an improved version of the relativistic mean field theory (RMF) at a finite temperature, where, in addition to the...

The effect of neutrino oscillations on the thermodynamic characteristics of three-flavor hot quark matter in beta-equilibrium that is opaque for neutrinos is examined in terms of the local SU(3) Nambu-Jona- Lasinio (NJL) model which also accounts for the ‘t Hooft interaction that leads to quark flavor mixing. The thermodynamic characteristics of qu...

В рамках локальной SU(3) модели Намбу – Иона-Лазинио (NJL), в которой учтено также приводящего к смешиванию кварковых ароматов взаимодействие 'т Хоофта, исследуется влияние нейтринных осцилляций на термодинамические характеристики горячей β-равновесной трехароматной и непрозрачной для нейтрино кварковой материи. Для двух значений температуры T=[60...

Изучены свойства адрон-кварковых гибридных звезд, когда кварковая фаза описывается в рамках локальной SU(3) модели Намбу-Иона-Лазинио (НИЛ) с учетом вклада векторного и аксиально-векторного взаимодействия между кварками, а адронная фаза - в модели релятивистского среднего поля (РСП). Для разных значений константы векторной связи GV рассчитаны уравн...

The thermodynamic characteristics of hot $\beta$-equilibrium three-flavor quark matter with neutrino confinement are studied in terms of the local SU(3) Nambu-Jona-Lasinio (NJL) model, which also accounts for the 't Hooft interaction which leads to mixing of quark flavors. For different temperatures $T \in [20 \div 100]$ MeV and baryon number densi...

The properties of hadron-quark hybrid stars are studied when the quark phase is described in terms of a local SU(3) Nambu--Jona-Lasinio (NJL) model taking into account the contribution of the vector and axial-vector interaction between the quarks, and the hadronic phase, in the relativistic mean field (RMF) model. For different values of the vector...

The properties of hadron-quark hybrid stars are studied when the quark phase is described in terms of a local SU(3) Nambu--Jona-Lasinio (NJL) model taking into account the contribution of the vector and axial-vector interaction between the quarks, and the hadronic phase, in the relativistic mean field (RMF) model. For different values of the vector...

Within the local SU (3) Nambu-Iona-Lasinio (NJL) model, which also takes into account the 't Hooft interaction that leads to mixing of quark flavors, the thermodynamic characteristics of hot β-equilibrium three-flavor quark matter with neutrino confinement are investigated. For different values of temperature T∈ [20÷100] MeV and baryon charge densi...

В рамках локальной SU(3) модели Намбу - Иона-Лазинио (NJL), в которой учтено также взаимодействие Шт Хоофта, приводящее к смешиванию кварковых ароматов, исследуются термодинамические характеристики горячей  -равновесной трехароматной кварковой материи при удержании нейтрино. Для разных значений температуры T [20  100] МэВ и плотности барионного...

The thermodynamic characteristics of hot β -equilibrium electrically neutral three-flavor quark matter at neutrino confinement are investigated. For the thermodynamic description of such a quark-lepton system, the local SU (3) Nambu-Jona-Lasinio (NJL) model is used, in which also takes into account the 't Hooft interaction, leading to the quark fla...

Hot Quark Matter

The thermodynamic characteristics of hot β-equilibrium, electrically neutral, three-flavor quark matter with neutrino confinement are studied. This kind of quark-lepton system is described thermodynamically using a local SU(3) Nambu - Jona-Lasinio (NJL) model that includes the ‘t Hooft interaction, leading to a mixing effect for the quark flavors....

ABSTRACT Hybrid Star Properties within the Nambu - Jona-Lasinio (NJL) Model for Quark Matter and Relativistic Mean Field (RMF) Model for Hadronic Matter. G.B. Alaverdyan Yerevan State University We study the properties of compact stars by taking into account the hadron-quark phase transition, as a result of which in the central part of the star i...

We study the hadron–quark hybrid equation of state (EOS) of compact-star matter. The Nambu–Jona-Lasinio (NJL) local SU (3) model with vector-type interaction is used to describe the quark matter phase, while the relativistic mean field (RMF) theory with the scalar-isovector δ-meson effective field is adopted to describe the hadronic matter phase. I...

We study the hadron-quark hybrid equation of state (EOS) of compact-star matter. The Nambu-Jona-Lasinio (NJL) local SU(3) model with vector-type interaction is used to describe the quark matter phase, while the relativistic mean field (RMF) theory with scalar-isovector $\delta$-meson effective field adopted to describe the hadronic matter phase. It...

The effect of model parameters in the equation of state for quark matter on the magnitude of the maximum mass of hybrid stars is examined. Quark matter is described in terms of the extended MIT bag model including corrections for one-gluon exchange. For nucleon matter in the range of densities corresponding to the phase transition, a relativistic e...

The integral parameters of neutron stars are studied taking into account the hadron-quark phase transition, which leads to the formation of a core of quark matter in the central part of a star. The quark matter is described using the local Nambu - Jona-Lasinio (NJL) model. The thermodynamic characteristics of the hadron matter are calculated in the...

The integral parameters of neutron stars are studied taking into account the hadron-quark phase transition, which leads to the formation of a core of quark matter in the central part of a star. The quark matter is described using the local Nambu-Jona-Lasinio (NJL) model. The thermodynamic characteristics of the hadron matter are calculated in the f...

The effect of model parameters in the equation of state for quark matter on the magnitude of the maximum mass of hybrid stars is examined. Quark matter is described in terms of the extended MIT bag model including corrections for one-gluon exchange. For nucleon matter in the range of densities corresponding to the phase transition, a relativistic e...

The article is devoted to some peculiarities of the propagation of sound wave emitted by a uniformly moving point source. We consider both subsonic and supersonic motions of the sound source. It is shown that in the case of subsonic motion, at each point inside the Mach cone, to a given moment of the sound receiving time two emission moments of tim...

We study the abrupt changes in the characteristics of compact stars due to the quark deconfinement phase transition. The hadronic phase is described within the relativistic mean-field theory, including a scalar-isovector δ-meson effective field. To describe the quark phase, we use the MIT bag model, in which the interactions between u, d and s quar...

We study the compact stars internal structure and observable characteristics alterations due to the quark deconfinement phase transition. To proceed with, we investigate the properties of isospin-asymmetric nuclear matter in the improved relativistic mean-field (RMF) theory, including a scalar-isovector \delta-meson effective field. In order to des...

The Maxwell and Glendenning construction scenarios of deconfinement phase transition in neutron star matter are investigated. The hadronic phase is described within the relativistic mean-field (RMF) theory, if also the scalar-isovector \delta-meson field is taken into account. The strange quark phase is described in the frame of MIT bag model, incl...

We study the compact stars internal structure and observable characteristics alterations due to the quark deconfinement phase transition. To proceed with, we investigate the properties of isospin- asymmetric nuclear matter in the improved relativistic mean-field (RMF) theory, including a scalar-isovector δ-meson effective field. In order to describ...

The deconfinement phase transition from hadronic matter to quark matter in the interior of compact stars is investigated. The hadronic phase is described in the framework of relativistic mean-field (RMF) theory, when also the scalar-isovector delta-meson effective field is taken into account. The MIT bag model for describing a quark phase is used....

The deconfinement phase transition from hadronic matter to quark matter in the interior of compact stars is investigated. The hadronic phase is described in the framework of relativ-istic mean-field (RMF) theory, when also the scalar-isovector δ-meson effective field is taken into account. The MIT bag model for describing a quark phase is used. The...

The Maxwell and Glendenning construction scenarios of deconfinement phase transition in neutron star matter are investigated. The hadronic phase is described within the relativistic mean-field (RMF) theory, if the scalar-isovector δ-meson field is also taken into account. The strange quark phase is described in the frame of MIT bag model, including...

The hadron-quark phase transition in the interior of compact stars is investigated, when the transition proceeds through a mixed phase. The hadronic phase is described in the framework of relativistic mean-field theory, when also the scalar-isovector delta-meson mean-field is taken into account. The changes of the parameters of phase transition cau...

The deconfinement phase transition from hadronic matter to quark matter in the interior of compact stars is investigated. The hadronic phase is described in the framework of relativistic mean-field (RMF) theory, when also the scalar- isovector $\delta$-meson effective field is taken into account. To describe a quark phase the MIT bag model is used....

The equation of state of neutron star matter is examined in terms of the relativistic mean-field theory, including a scalar-isovector δ-meson effective field. The constants of the theory are determined numerically so that the empirically known characteristics of symmetric nuclear matter are reproduced at the saturation density. The thermodynamic ch...

Equation of state for superdense nuclear matter is considered in the framework of relativistic mean-field theory, when the scalar-isovector -meson effective field is taken into account, as well. Assuming that the transition to the strange quark matter is a usual first-order phase transition described by Maxwells construction, the changes of the par...

The deconfinement phase transition from hadronic matter to quark matter in the interior of compact stars is investigated. The hadronic phase is described in the framework of relativistic mean-field (RMF) theory, when also the scalar-isovector delta-meson effective field is taken into account. The MIT bag model for describing a quark phase is used....

In the framework of the relativistic mean field theory, we have considered the equation of state of superdense nuclear matter, taking into account an effective scalar-isovector δ meson field. The effect of the δ meson field on the characteristics of a Maxwell-type quark phase transition has been studied. The quark phase is described with the aid of...

Series of neutron star models with strange quark cores are constructed on the basis of an extensive set of calculated realistic equations of state of superdense matter with quark-hadron phase transition. For some models a new local maximum on the stable branch of the star mass -central pressure diagram is revealed. This maximum arises along with th...

A broad sample of computed realistic equations of state of superdense matter with a quark phase transition is used to construct a series of models of neutron stars with a strange quark core. The integral characteristics of the stellar configurations are obtained: gravitational mass, rest mass, radius, relativistic moment of inertia, and red shift f...

An extensive set of realistic equations of state for superdense matter with a quark phase transition is derived on the basis of the three equations of state for neutron matter and the eight variants of strange quark-gluon plasmas in the MIT quark bag model. The characteristics of the phase transitions are described and the calculated equations of s...

We consider an equation of state that leads to a first-order phase transition from the nucleon state to the quark state with a transition parameter λ>3/2 (λ=ρQ/(ρN+P 0/c 2)) in superdense nuclear matter. Our calculations of integrated parameters for superdense stars using this equation of state show that on the stable branch of the dependence of st...

An equation of state is considered that, in superdense nuclear matter, results in a phase transition of the first kind from the nucleon state to the quark state with a transition parameter > 3/2 ( = Q /( N + P 0/c 2)). A calculation of the integrated parameters of superdense stars on the basis of this equation of state shows that on the stable bra...

Neutron stars in which the presence of a pion condensate causes a phase transition of the first order are investigated. Calculations are made for two equations of state of the nucleon component. The model of the pion condensate is that of a developed condensate, in which the presence of degenerate electrons and µ- mesons is taken account. Calculati...

To check the existence of superdense nucleus-like self-confined cosmic objects (pion stars) in the case of a highly hard equation of state (∂P/∂ρ = 1) the authors have calculated the maximum values of their masses for various densities at the surface. For such configurations the values of the radius and the relativistic moment of inertia are also c...

A theoretical analysis is presented of the problem of nuclear matter under intensive pion condensation. The equation of state in the problem is calculated for several sets of nuclear constants such that a nuclear plasma can form in a bounded system. The equation is used to simulate the physical characteristics of celestial bodies which exist even w...

An analysis is made of nuclear matter that has undergone intensive pion condensation. The equation of state is calculated for sets of nuclear constants such that the nuclear plasma can form a bound system, and is employed to investigate superdense model celestial bodies which can exist even if self-gravitation were absent. Notable features of these...

The average multiplicity of secondary particles in hA interactions is studied in the framework of the theory of multiple scattering. It is shown that the predictions of the leading-particle cascade model are in satisfactory agreement with the experimental data if the uncertainties in the values of the inelasticity coefficients for hN interactions a...

Experimental data on the momentum spectra of protons from the pA..-->..pX reaction at 19.2 GeV/c are analyzed, and the reasons why other investigators who analyzed these same data seemed to have detected ''bare'' particle states are discussed.

Momentum spectra of protons emitted in the pp-, pd- and pC-collisions at initial momenta of 4.3, 6.3 and 8.9 GeV/c have been measured at an angle of 103 mrad using a single-arm magnetic spectrometer. The experimental data are satisfactory reproduced within the framework of the multiple scattering model. The sensitivity of the pd-spectra calculation...

The experimental data on the cross sections of the reaction pA..-->..pX at large values of the transverse momentum transfer (p/sub transverse/GeV/c) are analyzed within the framework of the theory of multiple scattering.