Description
A very strong electromagnetic field can break the symmetry of the vacuum state, which is a genuinely non-perturbative effect [1]. The anticipated physical outcome depends on the field structure and the initial conditions. For example, a vacuum state should break in a near-critical electric field $E \sim E_S$ by virtue of electron-positron pair creation. Interaction of high-energy particles, propagating in a strong field, can also be altered non-perturbatively by vacuum loop corrections, enhanced by a strong field. As predicted by Ritus and Narozhny [2,3], this can happen if the field strength reached in the particle rest frame exceeds $E_S$ by orders of magnitude. While various setups to reach this regime experimentally are already suggested by injecting ultra-relativistic particles in the fields generated by lasers, dense bunches, or crystals, the theoretical predictions of the observable features revealing it are still in the shade, as they require an all-order resummation of strong-field QED loop corrections.
In this presentation, we will focus on scattering processes in a constant crossed field of strength $>10^3E_S$ ($\alpha\chi^{2/3} > 1$). We will recap the analytic structure of radiative corrections at one- and higher-loop orders, our current view on the Ritus-Narozhny conjecture, and the non-perturbative calculation techniques at hand [4,5]. We will also discuss challenges and our recent progress in the calculation of observables in the fully non-perturbative regime.
[1] A. Fedotov, A. Ilderton, F. Karbstein et al, Advances in QED with intense background fields, Phys. Rep. 1010, 1 (2023).
[2] V. I. Ritus, Radiative corrections in quantum electrodynamics with intense field and their analytical properties, Ann. Phys. 69, 555 (1972).
[3] N. B. Narozhny, Expansion parameter of perturbation theory in intense-field quantum electrodynamics, Phys. Rev. D 21, 1176 (1980).
[4] A. A. Mironov, S. Meuren, and A. M. Fedotov, Resummation of QED radiative corrections in a strong constant crossed field, Phys. Rev. D 102, 053005 (2020).
[5] A. A. Mironov and A. M. Fedotov, Structure of radiative corrections in a strong constant crossed field, Phys. Rev. D 105, 033005 (2022).
