Searcharxiv⌕ Search

arXiv subjects

S. A. Smolyansky

Publications and source records attributed to S. A. Smolyansky.

At least 37 records · Page 2Linked to original sources
arXiv2010

Role of vacuum polarization for the annihilation channel in a strong laser field

We consider vacuum polarization effects in the one-photon annihilation channel within a kinetic description of the e+ e- plasma produced from the vacuum in the focal spot of counter-propagating laser beams. This entails essential changes in the structure of the photon kinetic equation. We investigate the domain of large adiabaticity parameters gamma >> 1 where the photon radiation turns out to be very small. A more thorough examination of the domain gamma < 1 needs separate investigation. However, an exploratory study has shown that the one-photon annihilation channel can lead for some domains of laser field parameters (e.g., for the XFEL) to contributions accessible for observation.

physics.plasm-ph↗
arXiv2010

On the kinetic equation approach to pair production by time-dependent electric field

We investigate the quantum kinetic approach to pair production from vacuum by time-dependent electric field. Equivalence between this approach and the more familiar S-matrix approach is explicitly established for both scalar and fermion cases. For the particular case of a constant electric field exact solution for kinetic equations is provided and the accuracy of low-density approximation is estimated.

hep-ph↗
arXiv2010

Kinetics of Photon Radiation off an e-e+ Plasma created from the Vacuum in a Strong Laser Field

We consider the one-photon annihilation mechanism in a electron - positron quasiparticle plasma (EPP) created from the vacuum in a strong subcritical laser field due to the dynamical Schwinger mechanism. On the basis of a kinetic theory approach we show that the secondary photons have a radiation spectrum proportional to 1/k (flicker noise). This effect is very small for EPP excitations in the optical spectrum but can reach quite observable values in the gamma - ray region.

physics.plasm-ph↗
arXiv2010

A proposal for testing subcritical vacuum pair production with high power lasers

We present a proposal for testing the prediction of non-equilibrium quantum field theory below the Schwinger limit. The proposed experiments should be able to detect a measurable number of gamma rays resulting from the annihilation of pairs in the focal spot of two opposing high intensity laser beams. We discuss the dependence of the expected number of gamma rays with the laser parameters and compare with the estimated background level of gamma hits for realistic laser conditions.

hep-ph↗
arXiv2009

Kinetics of parton- antiparton plasma vacuum creation in the time - dependent chromo - electric fields of arbitrary polarization

The kinetic equation of non - Markovian type for description of the vacuum creation of parton - antiparton pairs under action of a space homogeneous time - dependent chromo - electric field of the arbitrary polarization is obtained on the strict non - pertubative foundation in the framework of the oscillator representation. A comparison of the effectiveness of vacuum creation with the case of linear polarization one is fulfilled.

hep-ph↗
arXiv2008

Kinetic description of W and Z boson creation in the early universe

We consider an alternative mechanism for the production of the cosmic microwave background (CMB) radiation. It is basically due to vacuum pair creation (VPC) of vector bosons (W and Z) as a consequence of a rapid W and Z mass generation during the electroweak phase transition in the early Universe. The mechanism is as follows: after their pair crreation, the vector bosons may either annihilate directly into photons or decay into leptons and quarks which subsequently annihilate as lepton-antilepton and quark-antiquark pairs into photons. Preliminary estimates show that the number of CMB photons obtained this way can be sufficient to explain the presently observed CMB photon density. In this contribution we present an exactly soluble model for vacuum pair creation kinetics.

hep-ph↗
arXiv2008

Dynamical Schwinger effect and high-intensity lasers. Realising nonperturbative QED

We consider the possibility of experimental verification of vacuum e^+e^- pair creation at the focus of two counter-propagating optical laser beams with intensities 10^{20}-10^{22} W/cm^2, achievable with present-day petawatt lasers, and approaching the Schwinger limit: 10^{29} W/cm^2 to be reached at ELI. Our approach is based on the collisionless kinetic equation for the evolution of the e^+ and e^- distribution functions governed by a non-Markovian source term for pair production. As possible experimental signals of vacuum pair production we consider e^+e^- annihilation into gamma-pairs and the refraction of a high-frequency probe laser beam by the produced e^+e^- plasma. We discuss the dependence of the dynamical pair production process on laser wavelength, with special emphasis on applications in the X-ray domain (X-FEL), as well as the prospects for μ^+μ^- and π^+π^- pair creation at high-intensity lasers. We investigate perspectives for using high-intensity lasers as ``boosters'' of ion beams in the few-GeV per nucleon range, which is relevant, e.g., to the exploration of the QCD phase transition in laboratory experiments.

physics.plasm-ph↗
arXiv2007

Inertial mechanism: dynamical mass as a source of particle creation

A kinetic theory of vacuum particle creation under the action of an inertial mechanism is constructed within a nonpertrubative dynamical approach. At the semi-phenomenological level, the inertial mechanism corresponds to quantum field theory with a time-dependent mass. At the microscopic level, such a dependence may be caused by different reasons: The non-stationary Higgs mechanism, the influence of a mean field or condensate, the presence of the conformal multiplier in the scalar-tensor gravitation theory etc. In what follows, a kinetic theory in the collisionless approximation is developed for scalar, spinor and massive vector fields in the framework of the oscillator representation, which is an effective tool for transition to the quasiparticle description and for derivation of non-Markovian kinetic equations. Properties of these equations and relevant observables (particle number and energy densities, pressure) are studied. The developed theory is applied here to describe the vacuum matter creation in conformal cosmological models and discuss the problem of the observed number density of photons in the cosmic microwave background radiation. As other example, the self-consistent evolution of scalar fields with non-monotonic self-interaction potentials (the W-potential and Witten - Di Vecchia - Veneziano model) is considered. In particular, conditions for appearance of tachyonic modes and a problem of the relevant definition of a vacuum state are considered.

hep-ph↗
arXiv2007

Laser acceleration of ion beams

We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.

physics.acc-ph↗
arXiv2005

Pair production and optical lasers

Electron-positron pair creation in a standing wave is explored using a parameter-free quantum kinetic equation. Field strengths and frequencies corresponding to modern optical lasers induce a material polarisation of the QED vacuum, which may be characterised as a plasma of e^+ e^- quasiparticle pairs with a density of ~10^{20}cm^{-3}. The plasma vanishes almost completely when the laser field is zero, leaving a very small residual pair density, n_r, which is the true manifestation of vacuum decay. The average pair density per period is proportional to the laser intensity but independent of the frequency, ν. The density of residual pairs also grows with laser intensity but n_r \propto ν^2. With optical lasers at the forefront of the current generation, these dynamical QED vacuum effects may generate 5-10 observable two-photon annihilation events per laser pulse.

nucl-th↗
arXiv2004

Vacuum creation of massive vector bosons and its application to a conformal cosmological model

In the simple model of a massive vector field in flat space-time, we derive a kinetic equation of non-Markovian type, describing the vacuum pair creation under the action of external fields of different nature. We use for this aim the non-perturbative methods of kinetic theory in combination with a new element when the transition of the instantaneous quasiparticle representation is realized within the oscillator (holomorphic) representation. We study in detail the process of vacuum creation of vector bosons generated by a time-dependent boson mass in accordance with a conformal-invariant scalar-tensor gravitational theory and its cosmological application. It is indicated that the choice of the equation of state (EoS) of the Universe allows to obtain a number density of the vector bosons that is sufficient to explain the observed number density of photons in the cosmic microwave background radiation. It is shown that the vector boson gas created from the vacuum is in a strong non-equilibrium state and corresponds to a cold dust-like EoS.

hep-ph↗
arXiv2004

Pulsations of the electron-positron plasma in the field of optical lasers

The possibility to observe vacuum electron-positron pair creation due to a powerful optical laser pulse is discussed. We employ a quantum kinetic formulation of the problem with a source term describing the vacuum pair production in a homogeneous electric field with arbitrary time dependence (dynamical Schwinger mechanism). For a periodic field weak in comparison with the critical value E_{cr}=m^2/|e|, the electron-positron plasma density changes approximately periodically with twice the field frequency. Under these conditions, the mean value $ $ for the density per period in the volume lambda^3 is a more appropriate characteristic quantity than the residual density n_r which is taken over an integer number of field periods and calculated using the imaginary time method. The value is proportional to the squared field intensity and does not depend on the frequency. We show that in terms of the parameter an optical laser can be more effective than a X-ray one. We expect that it is possible to observe the vacuum creation effect not only by means of the planned X-ray free electron lasers but already at present-day optical lasers.

physics.plasm-ph↗
arXiv2004

Vacuum creation of quarks at the time scale of QGP thermalization and strangeness enhancement in heavy-ion collisions

The vacuum parton creation in quickly varying external fields is studied at the time scale of order 1 fm/$c$ typical for the quark-gluon plasma formation and thermalization. To describe the pre-equilibrium evolution of the system the transport kinetic equation is employed. It is shown that the dynamics of production process at times comparable with particle inverse masses can deviate considerably from that based on classical Schwinger-like estimates for homogeneous and constant fields. One of the effects caused by non-stationary chromoelectric fields is the enhancement of the yield of $s\bar{s}$ quark pairs. Dependence of this effect on the shape and duration of the field pulse is studied together with the influence of string fusion and reduction of quark masses.

nucl-th↗
arXiv2004

The kinetic equation for the quark Wigner function in strong gluon field

The Vlasov type quantum kinetic equation for deconfined quarks in strong quasi-classical gluon field is derived in the covariant single-time formalism. The equations system for the Wigner function components is obtained as a result of spinor and color decomposition. The field-free and vacuum solutions of the kinetic equation are found, and the conservation laws are derived. The flux-tube configuration of gluon field is discussed in detail.

hep-ph↗
arXiv2003

Kinetic Theory of the Quantum Field Systems With Unstable Vacuum

The description of quantum field systems with meta-stable vacuum is motivated by studies of many physical problems (the decay of disoriented chiral condensate, the resonant decay of CP-odd meta-stable states, self-consistent model of QGP pre-equilibrium evolution, the phase transition problem in the systems with broken symmetry etc). A non-perturbative approach based on the kinetic description within the framework of the quasi-particle representation was proposed here. We restrict ourselves to scalar field theory with potentials of polynomial type. The back reaction mechanism, i.e. the particle production influence on background field is also discussed. Using the oscillator representation, we derive the generalized kinetic equation with non-pertrubative source term for description of particle-antiparticle creation under action of background field and equation of motion for it. As an illustrative example we consider one-component scalar theory with double-well potential. On this example, we study some features of proposed approach, in particular, the selection problem of stable vacuum state, what allows to avoid appearance of tachyonic regimes. The similar analysis is possible for some other models of such kind: the Friedberg-Lee model, the non-linear of $η$ -- meson model of Witten--Di Vecchia--Veneziano, end so on.

hep-th↗
arXiv2003

The kinetic description of vacuum particle creation in the oscillator representation

The oscillator representation is used for the non-perturbative description of vacuum particle creation in a strong time-dependent electric field in the framework of scalar QED. It is shown that the method can be more effective for the derivation of the quantum kinetic equation (KE) in comparison with the Bogoliubov method of time-dependent canonical transformations. This KE is used for the investigation of vacuum creation in periodical linear and circular polarized electric fields and also in the case of the presence of a constant magnetic field, including the back reaction problem. In particular, these examples are applied for a model illustration of some features of vacuum creation of electron-positron plasma within the planned experiments on the X-ray free electron lasers.

hep-th↗
arXiv2002

Kinetics of Vacuum Pair Creation in Strong Electromagnetic Fields

We study particle - antiparticle pair production under action of a strong time dependent space homogeneous electric field at the presence of a collinear constant magnetic field. We derive the kinetic equation for a such field configuration for fermions and bosons in the framework of the Schwinger mechanism of vacuum tunneling. We show the enhancement of pair production for fermions with the increasing of the magnetic field as in the case of the constant electromagnetic field. We have constructed closed set of equations, which can be applied to some actual problems with manifestation of strong electromagnetic fields, e.g., it is essential in the framework of the Flux Tube Model of Quark - Gluon Plasma generation; for describing some cosmological objects and especially because of the planned experiments on creation of subcritical fields in the X-Free Electron Laser pulses.

hep-ph↗