научный журнал по физике Журнал экспериментальной и теоретической физики ISSN: 0044-4510

О научном журнале«Журнал экспериментальной и теоретической физики»

Журнал экспериментальной и теоретической физики издается с 1931 года как преемник физической части Журнала Русского физико-химического общества (ЖРФХО).

Журнал публикует статьи, представляющие собой результаты экспериментальных и теоретических исследований по фундаментальным вопросам физики: теории поля, астрофизике, атомной и молекулярной физике, физике плазмы, физике конденсированного состояния. Журнал выходит на русском языке и в переводе на английский язык.

Архив научных статейиз журнала «Журнал экспериментальной и теоретической физики»

  • A NOVEL APPROACH TO THE STUDY OF CONFORMALITY IN THE SU(3) THEORY WITH MULTIPLE FLAVORS

    BROWER, HASENFRATZ A., REBBI C., WEINBERG E., WITZEL O. — 2015 г.

    We investigate the transition between spontaneous chiral symmetry breaking and conformal behavior in the SU(3) theory with multiple fermion flavors. We propose a new strategy for studying this transition. Instead of changing the number of flavors, we lift the mass of a subset of the fermions, keeping the rest of the fermions near the massless chiral limit in order to probe the transition.

  • ACCURATE MEASUREMENT OF THE STICKING TIME AND STICKING PROBABILITY OF RB ATOMS ON A POLYDIMETHYLSILOXANE COATING

    ATUTOV S.N., PLEKHANOV A.I. — 2015 г.

    We present the results of a systematic study of Knudsen''s flow of Rb atoms in cylindrical capillary cells coated with a polydimethylsiloxane (PDMS) compound. The purpose of the investigation is to determine the characterization of the coating in terms of the sticking probability and sticking time of Rb on the two types of coating of high and medium viscosities. We report the measurement of the sticking probability of an Rb atom to the coating equal to 4.3 • 10 -5, which corresponds to the number of bounces 2.3 • 10 4 at room temperature. These parameters are the same for the two kinds of PDMS used. We find that at room temperature, the respective sticking times for high-viscosity and medium-viscosity PDMS are 22 ± 3 ps and 49 ± 6 μs. These sticking times are about million times larger than the sticking time derived from the surface Rb atom adsorption energy and temperature of the coating. A tentative explanation of this surprising result is proposed based on the bulk diffusion of the atoms that collide with the surface and penetrate inside the coating. The results can be important in many resonance cell experiments, such as the efficient magneto-optical trapping of rare elements or radioactive isotopes and in experiments on the light-induced drift effect.

  • BICEP2 IN CORPUSCULAR DESCRIPTION OF INFLATION

    DVALI G., GOMEZ C. — 2015 г.

    A corpuscular quantum description of inflation shows that there is no fundamental problem with trans-Planckian excursions of the inflaton field up to about 100 Planck masses, with the upper bound coming from the corpuscular quantum effects. In this description, the r parameter measures the ratio of occupation numbers of gravitons versus inflatons, which, according to BICEP2, was roughly a half at the time of 60 e-foldings prior to the end of inflation. We stress that in a non-Wilsonian UV self-completion of gravity, any trans-Planckian mode coupled to the inflaton is a black hole. Unlike the Wilsonian case, integrating them out gives an exponentially suppressed effect and is unable to prevent trans-Planckian excursions of the inflaton field.

  • CATHODOAND PHOTOLUMINESCENCE INCREASE IN AMORPHOUS HAFNIUM OXIDE UNDER ANNEALING IN OXYGEN

    ALIEV V. SH., GRITSENKO V.A., IVANOVA E.V., PUSTOVAROV V.A., YELISSEYEV A.P., ZAMORYANSKAYA M.V. — 2015 г.

    Cathodo- and photoluminescence of amorphous nonstoichiometric films of hafnium oxide are studied with the aim to verify the hypothesis that oxygen vacancies are responsible for the luminescence. To produce oxygen vacancies, hafnium oxide was enriched in surplus metal during synthesis. To reduce the oxygen concentration, the film was annealed in oxygen. A qualitative control of the oxygen concentration was carried out by the refractive index. In the initial, almost stoichiometric films we observed a 2.7-eV band in cathodoluminescence. Annealing in oxygen results in a considerable increase in its intensity, as well as in the appearance of new bands at 1.87, 2.14, 3.40, and 3.6 eV. The observed emission bands are supposed to be due to single oxygen vacancies and polyvacancies in hafnium oxide. The luminescence increase under annealing in an oxygen atmosphere may be a result of the emission quenching effect.

  • COMPLETING LORENTZ VIOLATING MASSIVE GRAVITY AT HIGH ENERGIES

    BIAS D., SIBIRYAKOV S. — 2015 г.

    Theories with massive gravitons are interesting for a variety of physical applications, ranging from cosmological phenomena to holographic modeling of condensed matter systems. To date, they have been formulated as effective field theories with a cutoff proportional to a positive power of the graviton mass m g and much smaller than that of the massless theory (Mp=10 19 GeV in the case of general relativity). In this paper, we present an ultraviolet completion for massive gravity valid up to a high energy scale independent of the graviton mass. The construction is based on the existence of a preferred time foliation combined with spontaneous condensation of vector fields. The perturbations of these fields are massive and below their mass, the theory reduces to a model of Lorentz violating massive gravity. The latter theory possesses instantaneous modes whose consistent quantization we discuss in detail. We briefly study some modifications to gravitational phenomenology at low-energies. The homogeneous cosmological solutions are the same as in the standard cosmology. The gravitational potential of point sources agrees with the Newtonian one at distances small with respect to m g -1. Interestingly, it becomes repulsive at larger distances.

  • DOUBLE HIGGS PRODUCTION AT LHC, SEE-SAW TYPE-II AND GEORGI-MACHACEK MODEL

    GODUNOV S.I., VYSOTSKY M.I., ZHEMCHUGOV E.V. — 2015 г.

    The double Higgs production in the models with isospin-triplet scalars is studied. It is shown that in the see-saw type-II model, the mode with an intermediate heavy scalar, pp → H + X → 2h + X, may have the cross section that is comparable with that in the Standard Model. In the Georgi-Machacek model, this cross section could be much larger than in the Standard Model because the vacuum expectation value of the triplet can be large.

  • DYNAMICS OF CHARGED PLANAR GEOMETRY IN TILTED AND NONTILTED FRAMES

    SHARIF M., ZAEEM UL HAQ BHATTI M. — 2015 г.

    We investigate the dynamics of charged planar symmetry with an anisotropic matter field subject to a radially moving observer called a tilted observer. The Einstein-Maxwell field equations are used to obtain a relation between nontilted and tilted frames and between kinematical and dynamical quantities. Using the Taub mass formalism and conservation laws, two evolution equations are developed to analyze the inhomogeneities in the tilted congruence. It is found that the radial velocity (due to the tilted observer) and the electric charge have a crucial effect on the inhomogeneity factor. Finally, we discuss the stability in the nontilted frame in the pure diffusion case and examine the effects of the electromagnetic field.

  • DYNAMICS OF EXCITED INSTANTONS IN THE SYSTEM OF FORCED GURSEY NONLINEAR DIFFERENTIAL EQUATIONS

    AYDOGMUS F. — 2015 г.

    Тhе Gиrsеу mоdеl is а 4D соnfоrmаllу invаriаnt риrе fеrmiоniс mоdеl with а nоnlinеаr sрinоr sеlf-соирlеd tеrm. Gиrsеу рrороsеd his mоdеl аs а роssiblе bаsis fоr а иnitаrу dеsсriрtiоn оf еlеmеntаrу раrtiсlеs fоllоwing thе “Неisеnbеrg drеаm". In this рареr, wе соnsidеr thе sуstеm оf Gиrsеу nоnlinеаr diffеrеntiаl еqиаtiоns (GNDЕs) fоrmеd bу иsing thе Неisеnbеrg аnsаtz. Wе иsе it tо иndеrstаnd hоw thе bеhаviоr оf sрinоr-tуре Gиrsеу instаntоns саn bе аffесtеd bу ехсitаtiоns. Fоr this, thе rеgиlаr аnd сhаоtiс nиmеriсаl sоlиtiоns оf fоrсеd GNDЕs in рhаsе sрасе. А hiеrаrсhiсаl сlиstеr аnаlуsis mеthоd аrе invеstigаtеd bу соnstrисting thеir Роinсаrе sесtiоns fоr invеstigаting thе fоrсеd GNDЕs is аlsо рrеsеntеd.

  • ESTIMATES OF Z BOSON AND J/ψ PRODUCTION CROSS SECTIONS AT THE LARGE HADRON COLLIDER

    ALEXOPOULOS T., LEONTSINIS S. — 2015 г.

    We calculate the leading-order cross section for the associated production off Z and J=/ψ Processes that include associated production of electroweak bosons and heavy quarkonium can give valuable insight into the production mechanism of quarkonia. We conclude that this process is accessible by the LHC statistics.

  • EXACT SOLUTIONS FOR THE EVOLUTION OF A BUBBLE IN AN IDEAL LIQUID IN A UNIFORM EXTERNAL ELECTRIC FIELD

    ZUBAREV N.M., ZUBAREVA O.V. — 2015 г.

    The dynamics of a bubble in a dielectric liquid under the influence of a uniform external electric field are considered. It is shown that in the situation where the boundary motion is determined only by electrostatic forces, the special regime of fluid motion can be realized for which the velocity and electric field potentials are linearly related. In the two-dimensional case, the corresponding equations are reduced to an equation similar in structure to the well-known Laplacian growth equation, which, in turn, can be reduced to a finite number of ordinary differential equations. This allows us to obtain exact solutions for asymmetric bubble deformations resulting in the formation of a finite-time singularity (cusp).

  • EXPLORING THE SPECTRUM OF REGULARIZED BOSONIC STRING THEORY

    AMBJORN J., MAKEENKO Y. — 2015 г.

    We implement a UV regularization of the bosonic string by truncating its mode expansion and keeping the regularized theory “as diffeomorphism invariant as possible". We compute the regularized determinant of the 2d Laplacian for the closed string winding around a compact dimension, obtaining the effective action in this way. The minimization of the effective action reliably determines the energy of the string ground state for a long string and/or for a large number of space-time dimensions. We discuss the possibility of a scaling limit when the cutoff is taken to infinity.

  • EXPLORING VARIATIONS IN THE GAUGE SECTOR OF A SIX-DIMENSIONAL FLAVOUR MODEL

    FRERE J.-M., LIBANOV M., MOLLET S., TROITSKY S. — 2015 г.

    In the context of extra-dimensional models which describe three families of fermions, including their masses and mixings in terms of a single б-dimensional family, we explore possible variations, including in the geometry of the extra dimensions, and argue that the apparent plethora of variants does not lead to drastic changes in the expected phenomenology.

  • FLUX TUBE SPECTRA FROM APPROXIMATE INTEGRABILITY AT LOW ENERGIES

    DUBOVSKY S., FLAUGER R., GORBENKO V. — 2015 г.

    We provide a detailed introduction to a method we recently proposed for calculating the spectrum of excitations of effective strings such as QCD flux tubes. The method relies on the approximate integrability of the low-energy effective theory describing the flux tube excitations and is based on the thermodynamic Bethe ansatz. The approximate integrability is a consequence of the Lorentz symmetry of QCD. For excited states, the convergence of the thermodynamic Bethe ansatz technique is significantly better than that of the traditional perturbative approach. We apply the new technique to the lattice spectra for fundamental flux tubes in gluodynamics in D = 3 + 1 and D = 2 + 1, and to fc-strings in gluodynamics in D = 2 + 1. We identify a massive pseudoscalar resonance on the worldsheet of the confining strings in SU{3) gluodynamics in D = 3 + 1, and massive scalar resonances on the worldsheet of к = 2.3 strings in SU{6) gluodynamics in D = 2 + 1.

  • FULL SKY HARMONIC ANALYSIS HINTS AT LARGE ULTRA-HIGH ENERGY COSMIC RAY DEFLECTIONS

    TINYAKOV P.G., URBAN F.R. — 2015 г.

    The full-sky multipole coefficients of the ultra-high energy cosmic ray (UHECR) flux have been measured for the first time by the Pierre Auger and Telescope Array collaborations using a joint data set with E > 10 EeV. We calculate these harmonic coefficients in the model where UHECR are protons and sources trace the local matter distribution, and compare our results with observations. We find that the expected power for low multipoles (dipole and quadrupole, in particular) is sytematically higher than in the data: the observed flux is too isotropic. We then investigate to which degree our predictions are influenced by UHECR deflections in the regular Galactic magnetic field. It turns out that the UHECR power spectrum coefficients Ct are quite insensitive to the effects of the Galactic magnetic field, so it is unlikely that the discordance can be reconciled by tuning the Galactic magnetic field model. On the contrary, a sizeable fraction of uniformly distributed flux (representing for instance an admixture of heavy nuclei with considerably larger deflections) can bring simulations and observations to an accord.

  • HOLOGRAPHIC THERMALIZATION IN A QUARK CONFINING BACKGROUND

    AGEEV D.S., AREF’EVA I. YA. — 2015 г.

    We study holographic thermalization of a strongly coupled theory inspired by two colliding shock waves in a vacuum confining background. Holographic thermalization means a black hole formation, in fact, a trapped surface formation. As the vacuum confining background, we considered the well-know bottom-up AdS/QCD model that provides the Cornell potential and reproduces the QCD β-function. We perturb the vacuum background by colliding domain shock waves that are assumed to be holographically dual to heavy ions collisions. Our main physical assumption is that we can make a restriction on the time of trapped surface formation, which results in a natural limitation on the size of the domain where the trapped surface is produced. This limits the intermediate domain where the main part of the entropy is produced. In this domain, we can use an intermediate vacuum background as an approximation to the full confining background. We find that the dependence of the multiplicity on energy for the intermediate background has an asymptotic expansion whose first term depends on energy as Е 1/3, which is very similar to the experimental dependence of particle multiplicities on the colliding ion energy obtained from the RHIC and LHC. However, this first term, at the energies where the approximation of the confining metric by the intermediate background works, does not saturate the exact answer, and we have to take the nonleading terms into account.

  • HOLOGRAPHY BEYOND CONFORMAL INVARIANCE AND ADS ISOMETRY?

    BARVINSKY A.O. — 2015 г.

    We suggest that the principle of holographic duality can be extended beyond conformal invariance and AdS isometry. Such an extension is based on a special relation between functional determinants of the operators acting in the bulk and on its boundary, provided that the boundary operator represents the inverse propagators of the theory induced on the boundary by the Dirichlet boundary value problem in the bulk spacetime. This relation holds for operators of a general spin-tensor structure on generic manifolds with boundaries irrespective of their background geometry and conformal invariance, and it apparently underlies numerous 0(N o) tests of the AdS/CFT correspondence, based on direct calculation of the bulk and boundary partition functions, Casimir energies, and conformal anomalies. The generalized holographic duality is discussed within the concept of the “double-trace" deformation of the boundary theory, which is responsible in the case of large-N CFT coupled to the tower of higher-spin gauge fields for the renormalization group flow between infrared and ultraviolet fixed points. Potential extension of this method beyond the one-loop order is also briefly discussed.

  • LONG STRING DYNAMICS IN PURE GRAVITY ON A0IS3

    KIM J., PORRATI M. — 2015 г.

    We study the classiccal dynamics of a completion of pure AdS 3 gravity, whose only degrees of freedom are boundary gravitons and long strings. We argue that the best regime for describing pure gravity is that of heavy-strings, for which back-reaction e ffects on the metric must be taken into a ccount. We show that oncce back-reaction is properly a ccounted for, regular nite-energy states are produced by heavy strings even in the in nite-tension limit. Such a process is similar to, but di erent from, nucleation of space out of a bubble of nothing-

  • MODELING THE EVOLUTION OF GALACTIC MAGNETIC FIELDS

    YAR-MUKHAMEDOV D. — 2015 г.

    An analytic model for evolution of galactic magnetic fields in hierarchical galaxy formation frameworks is introduced. Its major innovative components include explicit and detailed treatment of the physics of merger events, mass gains and losses, gravitational energy sources and delays associated with formation of large-scale magnetic fields. This paper describes the model, its implementation, and core results obtained by its means.

  • NEUTRINOS IN ICECUBE FROM ACTIVE GALACTIC NUCLEI

    KALASHEV O., SEMIKOZ D., TKACHEV I. — 2015 г.

    Recently, the IceCube collaboration reported first evidence for the astrophysical neutrinos. Observation corresponds to the total astrophysical neutrino flux of the order of 3 • 10 -8 GeV • cm -2 • s -1 • sr -1 in a PeV energy range [1]. Active galactic nuclei (AGN) are natural candidate sources for such neutrinos. To model the neutrino creation in AGNs, we study photopion production processes on the radiation field of the Shakura-Sunyaev accretion discs in the black hole vicinity. We show that this model can explain the detected neutrino flux and at the same time avoids the existing constraints from the gamma-ray and cosmic-ray observations.

  • ON A CHIRAL ANALOG OF THE EINSTEIN-DE HAAS EFFECT

    ZAKHAROV V.I. — 2015 г.

    The Einstein de Haas e ffect reveals a transfer of anguar momentum from microscopi constituents (electrons) to a macroscopic body, but in the case of massless fermions, one could expect the transfer of the chirality of constituents to macroscopi helical motion. For such a picture to be consistent, the macroscopi helicity is to be conserved classically, to echo the conservation of the angular momentum of a rotating body. The cheliity conservation would in turn imposec on hydrodynamics of chiral liquids (whose constituents are massless fermions). Essentially, the hiral liquids are dissipation-free, on the classical level. Reservations and alternatives to this scenario are discussed.