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R. Shaisultanov

Publications and source records attributed to R. Shaisultanov.

11 recordsLinked to original sources
arXiv2026

Classical versus non-classical photon states for detecting vacuum non-linearity

Quantum electrodynamics (QED) predicts that the vacuum should behave as a non-linear medium. For many schemes aimed at verifying this fundamental prediction, the signal consists of one or more photons in a certain mode (determined by polarization $\sigma$ and wave-number $\boldsymbol{k}$) which would be empty in the absence of a QED vacuum non-linearity. Here we consider modifying these schemes by sending in a classical or non-classical (e.g., squeezed) photon state instead of the initial vacuum state in that mode. We find that the detectability can be improved significantly.

quant-ph↗
arXiv2025

Injection and Acceleration of Electrons by Radially Polarized Laser Pulses in a Plasma Channel

We consider injection and subsequent acceleration of electrons in narrow plasma channels irradiated by linearly and radially polarized ultraintense laser pulses. Using three-dimensional particle-in-cell simulations, we show that radially polarized beams significantly promote electron release from the channel walls and lead to enhanced injection. We compare an f/10 linearly polarized laser beam with two radially polarized cases: one focused more tightly (f/5) to match peak intensity, and one at equal f/10 to capture polarization effects. The radially polarized f/10 case injects approximately one-third more charge than the linearly polarized case, while the f/5 radially polarized case outperforms the linearly polarized one by about a factor of two in terms of maximum electron energy. These results highlight polarization and focusing geometry as key parameters for optimizing laser-driven electron acceleration setups.

physics.plasm-ph↗
arXiv2025

Collimated $ γ$-flash emission along the target surface irradiated by a laser at non-grazing incidence

The interaction of a high-power laser with a solid target provides ways to produce beams of $γ$-photons. For normal incidence of the laser on the target the beams usually appear in a form of two lobes, which are symmetric with respect to the laser propagation axis. In this work we demonstrate via three-dimensional particle-in-cell simulations a regime where for oblique incidence the emission of a collimated $γ$-photon beam is in the direction parallel to the target surface. The process is ascribed to the interference pattern in the electromagnetic field formed by the incident and reflected laser pulse. The electromagnetic field accelerates electrons to the GeV energy level, while temporarily directing their momentum along the target surface. Consequently, they emit a collimated $γ$-photon beam in the same direction. The dependencies of $γ$-photon emission on the incident angle, laser pulse polarization, power and duration and target thickness and preplasma are also addressed in the paper. The beam directionality is important for designing future experiments. In addition, this setup causes the generation of high-order harmonics propagating along the target surface.

physics.plasm-ph↗
arXiv2024

Attosecond gamma-ray flashes and electron-positron pairs in dyadic laser interaction with micro-wire

The interaction of an ultra-intense laser with matter is an efficient source of high-energy particles, with efforts directed towards narrowing the divergence and simultaneously increasing the brightness. In this paper we report on emission of highly collimated, ultrabright, attosecond $γ$-photons and generation of dense electron-positron pairs via a tunable particle generation scheme which utilizes the interaction of two high-power lasers with a thin wire target. Irradiating the target with a radially polarized laser pulse first produces a series of high charge, short duration, electron bunches with low transverse momentum. These electron bunches subsequently collide with a counter-propagating high intensity laser. Depending on the intensity of the counter-propagating laser, the scheme generates highly collimated ultra-bright GeV-level $γ$-beams and/or electron-positron plasma of solid density level.

physics.plasm-ph↗
arXiv2024

On the energy spectrum evolution of electrons undergoing radiation cooling

Radiative cooling of electron beams interacting with counter-propagating electromagnetic waves is analyzed, taking into account the quantum modification of the radiation friction force. Central attention is paid to the evolution of the energy spectrum of electrons accelerated by the laser wake field acceleration mechanism. As an electron beam loses energy to radiation, the mean energy decreases and the form of the energy distribution also changes due to quantum-mechanical spectral broadening.

physics.plasm-ph↗
arXiv2022

Field-assisted birefringent Compton scattering

Motivated by experimental initiatives such as the Helmholtz International Beamline for Extreme Fields (HIBEF), we study Compton scattering of x-rays at electrons in a strong external field (e.g., a strong optical laser) with special emphasis on the polarization-changing (i.e., birefringent) contribution on the amplitude level. Apart from being a potential background process for the planned vacuum birefringence experiments, this effect could be used for diagnostic purposes. Since the birefringent signal from free electrons (i.e., without the external field) vanishes in forward direction, the ratio of the birefringent and the normal (polarization conserving) contribution yields information about the field strength at the interaction point.

hep-ph↗
arXiv2009

What Magnetar Seismology can Teach us about the Magnetic Fields

The effect of magnetic fields on the frequencies of toroidal oscillations of neutron stars is derived to lowest order. Interpreting the fine structure in the QPO power spectrum of magnetars following giant flares reported by Strohmayer and Watts (2006) to be "Zeeman splitting" of degenerate toroidal modes, we estimate a crustal magnetic field of order 10^{15} Gauss or more. We suggest that residual m, -m symmetry following such splitting might allow beating of individual frequency components that is slow enough to be observed.

astro-ph.HE↗
arXiv2000

Vacuum Polarization in QED with World-Line Methods

Motivated by several recent papers on string-inspired calculations in QED, we here present our own use of world-line techniques in order to calculate the vacuum polarization and effective action in scalar and spinor QED with external arbitrary constant electromagnetic field configuration.

hep-th↗
arXiv1995

Backreaction in spinor QED and decoherence functional

Using the Schwinger-Keldysh (closed time path or CTP) and Feynman-Vernon influence functional formalisms we obtain an expression for the influence functional in terms of Bogoliubov coefficients for the case of spinor quantum electrodynamics. Then we derive a CTP effective action in semiclassical approximation and its cumulant expansion. Using it we obtain a equation for the description of the charged particle creation in electric field and of backreaction of charged quantum fields and their fluctuations on time evolution of this electric field. Also an intimate connection between CTP effective action and decoherence functional will allow us to analyze how macroscopic electromagnetic fields are ``measured'' through interaction with charges and thereby rendered classical.

hep-th↗
arXiv1995

On the string-inspired approach to QED in external field

Strassler's formulation of the string-derived Bern-Kosower formalism is extended to consider QED processes in homogeneous constant external field. A compact expression for the contribution of the one-loop with arbitrary number of external photon lines is given for scalar QED. Extension to spinor QED is shortly discussed.

hep-th↗