Critical Schwinger pair production. II. Universality in the deeply critical regime

Gies, Holger; Torgrimsson, Greger

doi:10.1103/physrevd.95.016001

Cited by 24 publications

(32 citation statements)

References 71 publications

(127 reference statements)

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“…[24][25][26]. However, there are only a few cases when such exact solutions are known.It was recently shown that near criticality, pair production exhibits universal properties similar to those of continuous phase transitions [27,28]. In our terminology, this corresponds to the situation when the Klein zone is relatively small.…”

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confidence: 90%

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Pair production from the vacuum by a weakly inhomogeneous space-dependent electric potential

2019

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There exists a clear physical motivation for theoretical studies of the vacuum instability related to the production of electron-positron pairs from a vacuum due to strong external electric fields. Various nonperturbative (with respect to the external fields) calculation methods were developed. Some of these methods are based on possible exact solutions of the Dirac equation. Unfortunately, there are only few cases when such solutions are known. Recently, an approximate but still nonperturbative approach to treat the vacuum instability caused by slowly varying t-electric potential steps (time dependent external fields that vanish as |t| → ∞), which does not depend on the existence of the corresponding exact solutions, was formulated in Ref. [S. P. Gavrilov, D. M. Gitman, Phys. Rev. D 95, 076013 (2017)]. Here, we present an approximate calculation method to treat nonperturbatively the vacuum instability in arbitrary weakly inhomogeneous x-electric potential steps (timeindependent electric fields of a constant direction that are concentrated in restricted space areas, which means that the fields vanish as |x| → ∞) in the absence of the corresponding exact solutions. Defining the weakly inhomogeneous regime in general terms, we demonstrate the universal character of the vacuum instability. This universality is associated with a large density of states excited from the vacuum by the electric field. Such a density appears in our approach as a large parameter. We derive universal representations for the total number and current density of the created particles. Relations of these representations with a locally constant field approximation for Schwinger's effective action are found.Center for Extreme Light Studies (XCELS), is slowly approaching the critical field strengths for observable pair production (see Ref.[13] for a review). Thus, there exists a clear physical motivation for theoretical studies of the vacuum instability. Firstly, it seems necessary to us to mention theoretical works devoted to various nonperturbative (with respect to the external field) calculation methods. Some of these methods are formulated for time-dependent external fields that vanish as |t| → ∞ (for t-electric potential steps in what follows) and are based on possible exact solutions of the Dirac equation; see, e.g., [6,[14][15][16][17]. Some of the methods are based on the analysis of the Schwinger effective action (see [18] for a review). The so-called derivative expansion approximation method, being applied to the Schwinger effective action, allows one to treat effectively arbitrary slowly varying in time strong fields [19,20]. We note that the locally constant field approximation (LCFA), which is to limit oneself to leading contributions of the derivative expansion of the effective action, allows for reliable results for electromagnetic fields of arbitrary strength; see, for example, Refs. [21,22]. An alternative approach to treat slowly varying t-electric potential steps, which does not depend on the existence of the corresponding exa...

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confidence: 90%

“…(23) is stronger than Eqs. (16) and (28) if the fields are weak, whereas they are equivalent if the fields are strong. For this reason, defining the scale ∆l m st in general terms, we choose the form (4).…”

Section: Introductionmentioning

confidence: 99%

Pair production from the vacuum by a weakly inhomogeneous space-dependent electric potential

2019

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“…the imaginary part of the one-loop QED effective action exhibits universal properties similar to those of continuous phase transitions [38,39]. According to our terminology, this occurs when the Klein zone is sufficiently small, as in the case of strong fields in the sharp-gradient regime.…”

Section: Sharp-gradient Configurationmentioning

confidence: 81%

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

2020

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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 (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.

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“…Switching off the backreaction, i.e. ignoring the integral in (9), yields no oscillations after the external field declines to zero, with both E and n constant.…”

Section: Sauter Pulsementioning

confidence: 99%

“…For ideas to boost the pair creation rate by superposing a strong, slowly varying field with a weak but fast field, see [5,6]. ‡ For further generalizations to include spatial gradients, see [8,9]. Other setups, not necessarily using lasers, are the field in the vicinity of a superheavy atomic nucleus [10][11][12][13][14], or a superposed XFEL beam [15,16].…”

Section: Introductionmentioning

confidence: 99%

Response of the QED(2) vacuum to a quench: Long-term oscillations of the electric field and the pair creation rate

Otto

Graeveling

Kämpfer

2019

Plasma Phys. Control. Fusion

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We consider -within QED(2) -the backreaction to the Schwinger pair creation in a time dependent, spatially homogeneous electric field. Our focus is the depletion of the external field as a quench and the subsequent longterm evolution of the resulting electric field. Our numerical solutions of the self consistent, fully backreacted dynamical equations exhibit a self-sustaining oscillation of both the electric field and the pair number depending on the coupling strength.

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Critical Schwinger pair production. II. Universality in the deeply critical regime

Cited by 24 publications

References 71 publications

Pair production from the vacuum by a weakly inhomogeneous space-dependent electric potential

Pair production from the vacuum by a weakly inhomogeneous space-dependent electric potential

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

Response of the QED(2) vacuum to a quench: Long-term oscillations of the electric field and the pair creation rate

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