scholarly journals Exactly solvable cases in QED with t-electric potential steps

2017 ◽  
Vol 32 (18) ◽  
pp. 1750105 ◽  
Author(s):  
T. C. Adorno ◽  
S. P. Gavrilov ◽  
D. M. Gitman
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Electric Potential ◽  
Constant Electric Field ◽  
Particle Creation ◽  
External Electromagnetic Field ◽  
Mean Values ◽  
Closed Form Solutions ◽  
Exactly Solvable ◽  
Klein Gordon

In this paper, we present in detail consistent QED (and scalar QED) calculations of particle creation effects in external electromagnetic field that correspond to three most important exactly solvable cases of t-electric potential steps: Sauter-like electric field, T-constant electric field, and exponentially growing and decaying electric fields. In all these cases, we succeeded to obtain new results, such as calculations in the modified configurations of the above-mentioned steps and detailed considerations of new limiting cases in already studied steps. As was recently discovered by us, the information derived from considerations of exactly solvable cases allows one to make some general conclusions about quantum effects in fields for which no closed form solutions of the Dirac (or Klein–Gordon) equation are known. In the present paper, we briefly represent such conclusions about universal behavior of vacuum mean values in slowly varying strong electric fields.

scholarly journals Vacuum instability in a constant inhomogeneous electric field: a new example of exact nonperturbative calculations

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
T. C. Adorno ◽  
S. P. Gavrilov ◽  
D. M. Gitman
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Transition Probabilities ◽  
Particle Creation ◽  
Field Configuration ◽  
Quantum Processes ◽  
Reflection And Transmission ◽  
Vacuum Instability ◽  
Klein Gordon

Abstract Basic quantum processes (such as particle creation, reflection, and transmission on the corresponding Klein steps) caused by inverse-square electric fields are calculated. These results represent a new example of exact nonperturbative calculations in the framework of QED. The inverse-square electric field is time-independent, inhomogeneous in the x -direction, and is inversely proportional to x squared. We find exact solutions of the Dirac and Klein–Gordon equations with such a field and construct corresponding in- and out-states. With the help of these states and using the techniques developed in the framework of QED with x-electric potential steps, we calculate characteristics of the vacuum instability, such as differential and total mean numbers of particles created from the vacuum and vacuum-to-vacuum transition probabilities. We study the vacuum instability for two particular backgrounds: for fields widely stretches over the x-axis (small-gradient configuration) and for the fields sharply concentrates near the origin $$x=0$$x=0 (sharp-gradient configuration). We compare exact results with ones calculated numerically. Finally, we consider the electric field configuration, composed by inverse-square fields and by an x-independent electric field between them to study the role of growing and decaying processes in the vacuum instability.

scholarly journals Asymptotic expansion of pair production probability in a time-dependent electric field

2015 ◽  
Vol 30 (35) ◽  
pp. 1550210
Author(s):  
Takashi Arai
Keyword(s):  
Asymptotic Expansion ◽  
Electric Field ◽  
Electric Fields ◽  
Quantum Electrodynamics ◽  
Strong Field ◽  
Order Term ◽  
Constant Electric Field ◽  
Particle Creation ◽  
Single Pulse ◽  
Time Interval

We study particle creation in a single pulse of an electric field in scalar quantum electrodynamics. We investigate the parameter condition for the case where the dynamical pair creation and Schwinger mechanism respectively dominate. Then, an asymptotic expansion for the particle distribution in terms of the time interval of the applied electric field is derived. We compare our result with particle creation in a constant electric field with a finite-time interval. These results coincide in an extremely strong field, however they differ in general field strength. We interpret the reason of this difference as a nonperturbative effect of high-frequency photons in external electric fields. Moreover, we find that the next-to-leading-order term in our asymptotic expansion coincides with the derivative expansion of the effective action.

scholarly journals Electric potential differences across auroral generator interfaces

2013 ◽  
Vol 31 (2) ◽  
pp. 251-261 ◽  
Author(s):  
J. De Keyser ◽  
M. Echim
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Electric Fields ◽  
Electric Potential ◽  
Equilibrium Configuration ◽  
Potential Difference ◽  
Field Profile ◽  
Electric Potential Difference ◽  
Electric Field Profile

Abstract. Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potential difference across the structure. The present paper explores the role of this cross-field electric potential difference in the situation where the interface is a tangential discontinuity. A self-consistent Vlasov description is used to determine the equilibrium configuration for different values of the transverse potential difference. A major observation is that there exist limits to the potential difference, beyond which no equilibrium configuration of the interface can be sustained. It is further demonstrated how the plasma densities and temperatures affect the type of electric field profile in the transition, with monopolar electric fields appearing primarily when the temperature contrast is large. These findings strongly support the observed association of monopolar fields with the plasma sheet boundary. The role of shear flow tangent to the interface is also examined.

Electronic structure of POPC phospholipids under constant electric field

2017 ◽  
Vol 31 (22) ◽  
pp. 1750157
Author(s):  
Jaciéli Evangelho de Figueiredo ◽  
Leandro Barros da Silva
Keyword(s):  
Electronic Structure ◽  
Dipole Moment ◽  
External Field ◽  
Electric Field ◽  
Electric Fields ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Constant Electric Field ◽  
Ab Initio Study ◽  
Electronic And Structural Properties

We report in the present paper an ab initio study on the electronic and structural properties of phospholipidic membranes under the influence of electric fields. We show that the external field alters the charge distribution of the molecule leading to a modification in the electric dipole moment. The torque on the phospholipid may then cause a transmembranar stress, which by its turn, weakens the membrane allowing to the formation of a pore.

scholarly journals ELECTROPHORESIS IN THE TOTAL (CONSTANT AND ALTERNATING) ELECTRIC FIELD. II. PECULIARITIES OF THE COMBINED IMPACT OF ALTERNATING AND CONSTANT ELECTRIC FIELDS

2020 ◽  
Vol 30 (4) ◽  
pp. 46-51
Author(s):  
B. P. Sharfarets ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Constant Electric Field ◽  
Electrokinetic Phenomena ◽  
Alternating Electric Fields ◽  
Alternating Electric Field ◽  
Electroacoustic Transducer ◽  
Dispersed Medium ◽  
Hydrodynamic Field ◽  
Combined Impact

The hydrodynamics of electrophoresis under the simultaneous impact of constant and alternating electric fields is considered. It has been shown that when the constant and alternating external fields are combined, the energy of the constant electric field is transferred into the alternating hydrodynamic field. An example is given of a dispersed medium in which a giant dispersion of the dielectric constant can arise, which in turn can contribute to an increase in the total electrophoresis rate. Analogies of the behavior of the considered dispersed medium with the action of an electroacoustic transducer based on the use of electrokinetic phenomena are given.

scholarly journals Radiation Problems Accompanying Carrier Production by an Electric Field in the Graphene

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 205
Author(s):  
Sergei P. Gavrilov ◽  
Dmitry M. Gitman ◽  
Vadim V. Dmitriev ◽  
Anatolii D. Panferov ◽  
Stanislav A. Smolyansky
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Electric Fields ◽  
Strong Field ◽  
Numerical Study ◽  
Spectral Composition ◽  
General System ◽  
External Electromagnetic Field ◽  
Quantum Radiation ◽  
Quantized Electromagnetic Field

A number of physical processes that occur in a flat one-dimensional graphene structure under the action of strong time-dependent electric fields are considered. It is assumed that the Dirac model can be applied to the graphene as a subsystem of the general system under consideration, which includes an interaction with quantized electromagnetic field. The Dirac model itself in the external electromagnetic field (in particular, the behavior of charged carriers) is treated nonperturbatively with respect to this field within the framework of strong-field QED with unstable vacuum. This treatment is combined with a kinetic description of the radiation of photons from the electron-hole plasma created from the vacuum under the action of the electric field. An interaction with quantized electromagnetic field is described perturbatively. A significant development of the kinetic equation formalism is presented. A number of specific results are derived in the course of analytical and numerical study of the equations. We believe that some of predicted effects and properties of considered processes may be verified experimentally. Among these effects, it should be noted a characteristic spectral composition anisotropy of the quantum radiation and a possible presence of even harmonics of the external field in the latter radiation.

Pair creation in curved Snyder space

2020 ◽  
Vol 35 (04) ◽  
pp. 2050014 ◽  
Author(s):  
B. Hamil ◽  
M. Merad ◽  
T. Birkandan
Keyword(s):  
Electric Field ◽  
Hypergeometric Functions ◽  
Gordon Equation ◽  
Constant Electric Field ◽  
Pair Creation ◽  
Bogoliubov Transformation ◽  
Transformation Technique ◽  
Scalar Particles ◽  
Klein Gordon ◽  
Klein Gordon Equation

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.

Gravity

2017 ◽  
Vol 13 (2) ◽  
pp. 4689-4691
Author(s):  
Jim Goodman
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Potential ◽  
Gravitational Constant ◽  
Gordon Equation ◽  
Relativistic Correction ◽  
Equation Solution ◽  
Klein Gordon ◽  
The Magnetic Field ◽  
Klein Gordon Equation

Considering two balls of Z protons each near each other the residual electric potential V is calculated. Also the gravitational potential is calculated. The Gravitational constant is the same for both. Thus the electric field creates gravity. This calculation is possible because the multibody energy states are known exactly. The relativistic correction of 2 has been found from the Klein-Gordon Equation solution. This finding is an important step in reducing known forces to one field. Recall the electric field is generated by motion in the magnetic field of atoms of a magnetic dipole.  The mass is a function of the length of the magnetic dipole.

MULTISCALED ASYMPTOTIC EXPANSIONS FOR THE ELECTRIC POTENTIAL: SURFACE CHARGE DENSITIES AND ELECTRIC FIELDS AT ROUNDED CORNERS

2007 ◽  
Vol 17 (06) ◽  
pp. 845-876 ◽  
Author(s):  
PATRICK CIARLET ◽  
SAMIR KADDOURI
Keyword(s):  
Electric Field ◽  
Charge Density ◽  
Surface Charge ◽  
Electric Fields ◽  
Asymptotic Expansions ◽  
Electric Potential ◽  
Curvature Radius ◽  
Geometrical Shape ◽  
Empirical Formulas ◽  
Electrostatic Problem

We are interested in computing the charge density and the electric field at the rounded tip of an electrode of small curvature. As a model, we focus on solving the electrostatic problem for the electric potential. For this problem, Peek's empirical formulas describe the relation between the electric field at the surface of the electrode and its curvature radius. However, it can be used only for electrodes with either a purely cylindrical, or a purely spherical, geometrical shape. Our aim is to justify rigorously these formulas, and to extend it to more general, two-dimensional, or three-dimensional axisymmetric, geometries. With the help of multiscaled asymptotic expansions, we establish an explicit formula for the electric potential in geometries that coincide with a cone at infinity. We also prove a formula for the surface charge density, which is very simple to compute with the Finite Element Method. In particular, the meshsize can be chosen independently of the curvature radius. We illustrate our mathematical results by numerical experiments.

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