Narrow Results

We calculate the effective potential of a strong magnetic field induced by fermions with anomalous magnetic moments which couple to the electromagnetic field in the form of the Pauli interaction. For a uniform magnetic field, we find the explicit form of the effective potential. It is found that the non-vanishing imaginary part develops for a magnetic field stronger than a critical field and has a quartic form which is quite different from the exponential form of the Schwinger process. We also consider a linear magnetic field configuration as an example of inhomogeneous magnetic fields. We find that the imaginary part of the effective potential is nonzero even below the critical field and shows an exponentially decreasing behavior with respect to the inverse of the magnetic field gradient, which is the non-perturbative characteristics analogous to the Schwinger process. These results imply the instability of the strong magnetic field to produce fermion pairs as a purely magnetic effect. The possible applications to the astrophysical phenomena with strong magnetic field are also discussed.

We discuss the observational effects of the direct coupling of neutrino magnetic moment with electromagnetic field through Pauli interaction in extreme conditions. We calculate the neutrino pair creation rate from the instability of the strong magnetic field possibly in the vicinity of astrophysical compact objects and the enhancement of neutrino production rates in the high energy collider experiments as well as in the high energy cosmic ray experiments.

In this paper, we study the influence of the noncommutativity on the pairs creation of neutral particle–antiparticle in (1 + 2)d. Using the Seiberg–Witten maps, the modified Euler–Lagrange field equations up to first-order in the noncommutativity, parameter $𝜃$ is obtained and the Nikishov method based on Bogoliubov transformation is applied to calculate the density number of created neutral fermions. It is shown that the noncommutativity amplifies the density number N. In addition, when $𝜃=0$, we obtain the known results corresponding to the undeformed quantum fields.

In noncommutative phase space (NCPS), we investigate the pair creation rate for the problem of scalar and spinorial particles emerging from a vacuum under the influence of uniform external electromagnetic fields using the Schwinger formal technique. It is demonstrated that under specific conditions, where the speed of light c approaches the Fermi velocity ${\upsilon }_F$ and $\bar{\omega }\to {\omega }_c∕2$ (with ${\omega }_c=\frac{|e|\mathcal{ℬ}}{mc}$ representing the cyclotron frequency), the behavior of the Dirac oscillator problem in a uniform electromagnetic field within NCPS is akin to the monolayer graphene problem in NCPS. In addition, the production probability per unit volume per unit time is discussed, along with the limits of parameter deformations.

The spectral distribution of positron created by photon and the spectral distribution of photons radiated from electron in an oriented single crystal of intermediate thickness is calculated at intermediate energies. The energy loss of charged particles as well as photon absorption are taken into account. The used basic probabilities of processes include the action of field of axis as well as the multiple scattering of radiating electron or particles of the created pair (the Landau-Pomeranchuk-Migdal (LPM) effect).

The noncommutative Bianchi I curved space–time vierbeins and spin connections are derived. Moreover, the corresponding noncommutative Dirac equation as well as its solutions are presented. As an application within the quantum field theory approach using Bogoliubov transformations, the von Neumann fermion–antifermion pair creation quantum entanglement entropy is studied. It is shown that its behavior is strongly dependent on the value of the noncommutativity $\theta$ parameter, $k_{\perp }$-modes frequencies and the structure of the curved space–time. Various discussions of the obtained features are presented.

In this paper, incorporating the effect of the deformed commutation relation on de Sitter background, we studied the deformed Schwinger mechanism in (1+1) dimensions for scalars particle of spin-0 in a constant electric field. The Klein–Gordon equation is solved exactly and the wave function is given in term of hypergeometric functions. The canonical method based on a Bogoliubov transformation is applied. The pair creation probability and the density number of created particles are calculated.

We study the problem of pair creation of scalar particles by an electric field in curved Snyder space. We find exact solutions for the Klein–Gordon equation with a constant electric field in terms of hypergeometric functions. Then we calculate the pair creation probability and the number of created pairs of particles through Bogoliubov transformation technique.

Creation of charged massless fermion pair by a photon in a constant uniform magnetic field is considered in the one-loop approximation of the $(2+1)$-dimensional quantum electrodynamics (QED${}_{2+1}$). We calculate the elastic scattering amplitude (EAS) of photon using the polarization operator of photon in the above magnetic field obtained earlier in our work. We analyze the elastic scattering amplitude of photon at various values of the photon energy and magnetic field strength. Very simple analytical formulas for EAS of photon are obtained in the so-called quasi-classical region. In the massive quantum electrodynamics the elastic scattering amplitude of photon defines its “mass” squared in the presence of external electromagnetic field and the imaginary part of EAS describes the total probability of charged massive fermion pair creation in the electromagnetic field; we assume that it is the case and in the massless quantum electrodynamics.

In this paper, we study the creation of particles from the vacuum in monolayer graphene by an electromagnetic field in a noncommutative (NC) phase space coordinate considering the Schwinger method. For two different gauges, the probability of particle creation is calculated using the effective action, and special cases are considered. The essential result is that the noncommutativity of the phase space contributes to the effective action and consequently it has an influence on the process of pair creation from the vacuum.

We consider pair production phenomena in spatially homogeneous strong electric fields. We focus on spinor QED in two-dimensions and discuss the potential ambiguity in the adiabatic order assignment for the electromagnetic potential required to fix the renormalization subtractions. This ambiguity can be univocally fixed by imposing, at the semiclassical level, stress-energy conservation when both electric and gravitational backgrounds are present.

The spectral distribution of positron created by photon and the spectral distribution of photons radiated from electron in an oriented single crystal of intermediate thickness is calculated at intermediate energies. The energy loss of charged particles as well as photon absorption are taken into account. The used basic probabilities of processes include the action of field of axis as well as the multiple scattering of radiating electron or particles of the created pair (the Landau-Pomeranchuk-Migdal (LPM) effect).

We point out a problem of invariance in the usual “tunneling” method (Angheben et al., and following variants) frequently used to calculate the Hawking radiation in the semi-classical approximation. Indeed this naive “ΔW-only” method, which is good for flat space-time in Cartesian coordinates, does not work automatically in curvilinear coordinates since it is not coordinate invariant. Instead, using an invariant procedure analog to the one used by Popov for pair creation in constant electric field, we show that such creation-probability is zero due to a contribution of the time factor present in the complete action.