Perturbative methods for assisted nonperturbative pair production

We study electron and positron pair production from the vacuum by a strong slow electric field superimposed by a weak fast electric field pointing in an arbitrary direction as a perturbation (the dynamically assisted Schwinger mechanism). An analytical formula for the production number is derived on the basis of the perturbation theory in the Furry picture. The formula is found to be in good agreement with non-perturbative results obtained by numerically solving the Dirac equation if the perturbation is sufficiently weak and/or is not very slow. We also find analytically/numerically that the Schwinger mechanism becomes spin-dependent if the perturbation has a transverse component with respect to the strong electric field. The number difference between spin up and down particles is strongly suppressed by an exponential of the critical field strength if the frequency of the perturbation is small, while it is only weakly suppressed by powers of the critical field strength if the frequency is large enough. We also find that the spin-imbalance exhibits non-trivial oscillating behaviors in terms of the frequency of the perturbation, the azimuthal angle, and the momentum of produced particles.

Section: Analytical Discussion Based On Perturbation Theory In Thmentioning

confidence: 99%

Spin-dependent dynamically assisted Schwinger mechanism

Huang

Taya

2019

“…where a loss of analyticity is exhibited. While the integer value k manifests the periodicity in γ , the critical Keldysh parameter [30][31][32]40] γ cr = ln 2 ε , ε 1 (8) rules two different scenarios depending on whether γ ⊥ does or does not exceed the value of γ cr . Below we will describe further this point.…”

Section: Properties Of the Particle Spectrummentioning

confidence: 99%

“…This way, illuminating the crucial aspects from which an optimized version of the aforementioned enhancement could be reached. Two recent papers went a step further by providing analytical expressions for the total probability of produced pairs [31,32]. In these investigations a pertubative treatment in the weak field was used within the WKB and the world-line instanton methods, respectively.…”

Section: Introductionmentioning

confidence: 99%

Signatures of the Schwinger mechanism assisted by a fast-oscillating electric field

Villalba-Chávez

Müller

2019

The spontaneous production of electron-positron pairs from the vacuum-in a field configuration composed of a high-frequency electric mode of weak intensity and a strong constant electric field-is investigated. Asymptotic expressions for the single-particle distribution function ruling this nonperturbative process are established by considering the low-density approximation in the Boltzmann-Vlasov equation. An analytical formula for the density rate of yielded particles is established which is shown to manifest a nonperturbative dependence on both the strong and weak electric fields and to interpolate between the tunneling and multi-photon regimes. It is shown that-under appropriate circumstances-the produced plasma of electrons and positrons might reach densities for which their recombinations into high-energy photons occurs copiously. On the basis of this feature, an experimental setup for observing the dynamically-assisted Schwinger effect is put forward.

“…Nowadays, physicists commonly believe that by choosing the appropriate field configurations both in space-and timedomains one can amplify the pair production [18,19]. A wellknown procedure is to employ the bound states [20][21][22][23][24][25] in * qingzheng.lyu@mpi-hd.mpg.de some binding potentials as the bridge between the positive and negative energy states to enhance pair production.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of pair creation due to locality in bound-continuum interactions

et al. 2020

Electron-positron pair production from vacuum is studied in combined background fields, a binding electric potential well and a laser field. The production process is triggered by the interactions between the bound states in the potential well and the continuum states in the Dirac sea. By tuning the binding potential well, the pair production can be strongly affected by the locality of the bound states. The narrower bound states in position space are more efficient for pair production. This is in contrast to what is commonly expected that the wider extended bound states have larger region to interact with external fields and would thus create more particles. This surprise can be explained as the more localized bound states have a much wider extension in the momentum space, which can enhance the bound-continuum interactions in the creation process. This enhancement manifests itself in both perturbative and non-perturbative production regimes.