Quantum tunnelling from vacuum in multidimensions

Akal, Ibrahim; Moortgat‐Pick, Gudrid

doi:10.1103/physrevd.96.096027

Cited by 10 publications

(9 citation statements)

References 74 publications

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“…Furthermore, it facilitates in particular the role of such backgrounds with regard to the nonlocal nature of vacuum pair production. Recently, results in that direction have been presented in [85] demonstrating the validity of the techniques discussed in the present work. Figure 23.…”

Section: Discussionsupporting

confidence: 64%

“…Such a dependence has been analytically obtained for the case of a strong spatial Sauter field combined with a temporal Sauter field, treating both fields nonperturbatively [79]. Following analogous geometric arguments as discussed here, the present approach has been extended to spatiotemporal electric backgrounds E E E(t, x) with temporal sinusoidal or (super) Gaussian dependence [85] resulting in highly accurate predictions for the critical Keldysh parameter.…”

Section: Impact On Critical Thresholdmentioning

confidence: 90%

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Euclidean mirrors: enhanced vacuum decay from reflected instantons

Akal¹,

Moortgat‐Pick²

2018

J. Phys. G: Nucl. Part. Phys.

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We study the tunneling of virtual matter-antimatter pairs from the quantum vacuum in the presence of a spatially uniform, time-dependent electric background composed of a strong, slow field superimposed with a weak, rapid field. After analytic continuation to Euclidean spacetime, we obtain from the instanton equations two critical points. While one of them is the closing point of the instanton path, the other serves as an Euclidean mirror which reflects and squeezes the instanton. It is this reflection and shrinking which is responsible for an enormous enhancement of the vacuum pair production rate. We discuss how important features of two different mechanisms can be analysed and understood via such a rotation in the complex plane. a) Consistent with previous studies, we first discuss the standard assisted mechanism with a static strong field and certain weak fields with a distinct pole structure in order to show that the reflection takes place exactly at the poles. We also discuss the effect of possible sub-cycle structures. We extend this reflection picture then to weak fields which have no poles present and illustrate the effective reflections with explicit examples. An additional field strength dependence for the rate occurs in such cases. We analytically compute the characteristic threshold for the assisted mechanism given by the critical combined Keldysh parameter. We discuss significant differences between these two types of fields. For various backgrounds, we present the contributing instantons and perform analytical computations for the corresponding rates treating both fields nonperturbatively. b) In addition, we also study the case with a nonstatic strong field which gives rise to the assisted dynamical mechanism. For different strong field profiles we investigate the impact on the critical combined Keldysh parameter. As an explicit example, we analytically compute the rate by employing the exact reflection points. The validity of the predictions for both mechanisms is confirmed by numerical computations. arXiv:1706.06447v2 [hep-th] 18 Oct 2018 7 Summary 43 A Effect of inhomogeneities 45 -1 -(2.1)The rate R is determined by the imaginary part of the one-loop Euler-Heisenberg (EH) effective action [1,59]. One can analytically continue to Euclidean spacetime and integrate 2 It is important to note that the effect of assistance requires in general the nonperturbative treatment of the weak rapid field, see e.g. [6]. Such a treatment is realised in the reflection picture.

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Section: Discussionsupporting

confidence: 64%

Section: Impact On Critical Thresholdmentioning

confidence: 90%

Euclidean mirrors: enhanced vacuum decay from reflected instantons

Akal¹,

Moortgat‐Pick²

2018

J. Phys. G: Nucl. Part. Phys.

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“…Except for special spacetime inhomogeneities that essentially reduce to single-parameter inhomogeneities in light-front time E = E(t + z) [421] and "interpolating" coordinates E = E(t cos θ + z sin θ) [663], the semiclassical analyses for single-parameter inhomogeneities cannot be applied directly. Among the semi-classical methods, the worldline instanton method is rather easy to extend to multi-parameter inhomogeneities [664,665,666,667,668]. The problem reduces to finding classical solutions (worldline instantons) to the worldline action S wl = − τ 0 ( ẋ2 +m 2 +ieA•x).…”

Section: Semi-classical Methods and The Stokes Phenomenonmentioning

confidence: 99%

Advances in QED with intense background fields

Fedotov¹,

Ilderton²,

Karbstein³

et al. 2022

Preprint

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Upcoming and planned experiments combining increasingly intense lasers and energetic particle beams will access new regimes of nonlinear, relativistic, quantum effects. This improved experimental capability has driven substantial progress in QED in intense background fields. We review here the advances made during the last decade, with a focus on theory and phenomenology. As ever higher intensities are reached, it becomes necessary to consider processes at higher orders in both the number of scattered particles and the number of loops, and to account for non-perturbative physics (e.g. the Schwinger effect), with extreme intensities requiring resummation of the loop expansion. In addition to increased intensity, experiments will reach higher accuracy, and these improvements are being matched by developments in theory such as in approximation frameworks, the description of finite-size effects, and the range of physical phenomena analysed. Topics on which there has been substantial progress include: radiation reaction, spin and polarisation, nonlinear quantum vacuum effects and connections to other fields including physics beyond the Standard Model.

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“…Recently, such a coincidence for the leading order exponential factor has been observed between a weak Lorentzian and a super Gaussian approaching the rectangular barrier limit [18,19].…”

Section: Introductionmentioning

confidence: 80%

Super Gaussian enhancers in the Schwinger mechanism

Akal¹

2019

Commun. Theor. Phys.

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We study the Schwinger mechanism in the presence of an additional uniformly oriented, weak super Gaussian of integer order 4N + 2. Using the worldline approach, we determine the relevant critical points to compute the leading order exponential factor analytically. We show that increasing the parameter N gives rise to a strong dynamical enhancement. For N = 2, this effect turns out to be larger compared to a weak contribution of Sauter type. For higher orders, specifically, for the rectangular barrier limit, i.e. N → ∞, we approach the Lorentzian case as an upper bound. Although the mentioned backgrounds significantly differ in Minkowski spacetime, we show that the found coincidence applies due to identical reflection points in the Euclidean instanton plane. In addition, we also treat the background in perturbation theory following recent ideas. By doing so, we show that the parameter N determines whether the weak contribution behaves perturbatively or nonperturbatively with respect to the field strength ratio and, hence, reveals an interesting dependence on the background shape. In particular, we show that for backgrounds, for which higher orders in the field strength ratio turn out to be relevant, a proposed integral condition is not fulfilled. In view of these findings, the latter may serve as an indicator for the necessity of higher order contributions. arXiv:1712.05368v3 [quant-ph]

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Quantum tunnelling from vacuum in multidimensions

Cited by 10 publications

References 74 publications

Euclidean mirrors: enhanced vacuum decay from reflected instantons

Euclidean mirrors: enhanced vacuum decay from reflected instantons

Advances in QED with intense background fields

Super Gaussian enhancers in the Schwinger mechanism

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