Publications (42)
Quantum radiation reaction spectrum of electrons in plane waves
Greger Torgrimsson
In previous works we derived equations for the average momentum of high-energy electrons experiencing quantum radiation reaction (RR) in strong electromagnetic plane-wave backgroun…
Momentum correlation in pair production by spacetime dependent fields from scattered wave functions
Greger Torgrimsson
We consider Sauter-Schwinger pair production by electric fields that depend on both time and space, and . For space-independent fields, , momentum conserva…
Plasma dynamics at the Schwinger limit and beyond
Gert Brodin, Haidar Al-Naseri, Jens Zamanian +2
Strong field physics close to or above the Schwinger limit are typically studied with vacuum as initial condition, or by considering test particle dynamics. However, with a plasma…
Perturbative methods for assisted nonperturbative pair production
Greger Torgrimsson
In the dynamically assisted Schwinger mechanism, the pair production probability is significantly enhanced by including a weak, rapidly varying field in addition to a strong, slowl…
Solving the Dirac equation on a GPU for strong-field processes in multidimensional background fields
Greger Torgrimsson
In this paper, we show how to solve the Dirac equation, $(iγ^μ[\partial_μ+ieA_μ(t,{\bf x})]-m)Ï=0$, on a GPU. This is orders of magnitude faster than solving it on CPU and all…
Worldline instantons for nonlinear Breit-Wheeler pair production and Compton scattering
Gianluca Degli Esposti, Greger Torgrimsson
Worldline instantons have previously been used to study the probability of Schwinger pair production (both the exponential and pre-exponential parts) and photon-stimulated pair pro…
Conceptual Design Report for the LUXE Experiment
Halina Abramowicz, Uwe Hernandez Acosta, Massimo Altarelli +88
This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the Europe…
Momentum spectrum of nonlinear Breit-Wheeler pair production in space-time fields
Gianluca Degli Esposti, Greger Torgrimsson
We show how to use a worldline-instanton formalism to calculate, to leading order in the weak-field expansion, the momentum spectrum of nonlinear Breit-Wheeler pair production in f…
Trident pair production in plane waves: Coherence, exchange, and spacetime inhomogeneity
Victor Dinu, Greger Torgrimsson
We study the trident process in inhomogeneous plane wave background fields. We obtain compact analytical expressions for all terms in the probability, including the exchange part,…
Momentum spectrum of Schwinger pair production in four-dimensional e-dipole fields
Gianluca Degli Esposti, Greger Torgrimsson
We calculate the momentum spectrum of electron-positron pairs created via the Schwinger mechanism by a class of four-dimensional electromagnetic fields called e-dipole fields. To t…
Single and double nonlinear Compton scattering
Victor Dinu, Greger Torgrimsson
We study single, double and higher-order nonlinear Compton scattering where an electron interacts nonlinearly with a high-intensity laser and emits one, two or more photons. We stu…
Resummation of quantum radiation reaction and induced polarization
Greger Torgrimsson
In a previous paper we proposed a new method based on resummations for studying radiation reaction of an electron in a plane-wave electromagnetic field. In this paper we use this m…
Quantum radiation reaction: from interference to incoherence
Victor Dinu, Chris Harvey, Anton Ilderton +2
We investigate quantum radiation reaction in laser-electron interactions across different energy and intensity regimes. Using a fully quantum approach which also accounts exactly f…
Nonlinear trident in the high-energy limit: Nonlocality, Coulomb field and resummations
Greger Torgrimsson
We study nonlinear trident in laser pulses in the high-energy limit, where the initial electron experiences, in its rest frame, an electromagnetic field strength above Schwinger's…
The trident process in laser pulses
Victor Dinu, Greger Torgrimsson
We study the trident process in laser pulses. We provide exact numerical results for all contributions, including the difficult exchange term. We show that all terms are in general…
Vacuum refractive indices and helicity flip in strong-field QED
Victor Dinu, Tom Heinzl, Anton Ilderton +2
Vacuum birefringence is governed by the amplitude for a photon to flip helicity or polarisation state in an external field. Here we calculate the flip and non-flip amplitudes in ar…
Dynamically assisted Sauter-Schwinger effect - non-perturbative versus perturbative aspects
Greger Torgrimsson, Christian Schneider, Johannes Oertel +1
The Sauter-Schwinger effect predicts the creation of electron-positron pairs out of the quantum vacuum by a strong and slowly varying electric field. This effect can be dynamically…
Nonlinear photon trident versus double Compton scattering and resummation of one-step terms
Greger Torgrimsson
We study the photon trident process, where an initial photon turns into an electron-positron pair and a final photon under a nonlinear interaction with a strong plane-wave backgrou…
Worldline instantons for the momentum spectrum of Schwinger pair production in space-time dependent fields
Gianluca Degli Esposti, Greger Torgrimsson
We show how to use the worldline-instanton formalism to calculate the momentum spectrum of the electron-positron pairs produced by an electric field that depends on both space and…
Resummation of quantum radiation reaction in plane waves
Greger Torgrimsson
We propose a new approach to obtain the momentum expectation value of an electron in a high-intensity laser, including multiple photon emissions and loops. We find a recursive form…
Approximating higher-order nonlinear QED processes with first-order building blocks
Victor Dinu, Greger Torgrimsson
Higher-order tree-level processes in strong laser fields, i.e. cascades, are in general extremely difficult to calculate, but in some regimes the dominant contribution comes from a…
Quantum radiation reaction: Analytical approximations and obtaining the spectrum from moments
Greger Torgrimsson
We derive analytical approximations for spin-dependent quantum radiation reaction for locally constant and locally monochromatic fields. We show how to factor out fast spi…
Worldline instantons for nonperturbative particle production by space and time dependent gravitational fields
Philip Semrén, Greger Torgrimsson
We develop a worldline-instanton approach for calculating the momentum spectrum of particles produced by gravitational fields which depend on both space and time. The instantons ar…
Doubly assisted Sauter-Schwinger effect
Greger Torgrimsson, Johannes Oertel, Ralf Schützhold
We study electron-positron pair creation by a strong and slowly varying electric field, assisted by a weaker and more rapidly changing field (e.g., in the keV regime) plus an addit…
Schwinger pair production in spacetime fields: Moiré patterns, Aharonov-Bohm phases and Sturm-Liouville eigenvalues
Gianluca Degli Esposti, Greger Torgrimsson
We use a worldline-instanton formalism to study the momentum spectrum of Schwinger pair production in spacetime fields with multiple stationary points. We show that the interferenc…
Sauter-Schwinger pair creation dynamically assisted by a plane wave
Greger Torgrimsson, Christian Schneider, Ralf Schützhold
We study electron-positron pair creation by a strong and constant electric field superimposed with a weaker transversal plane wave which is incident perpendicularly (or under some…
Loops and polarization in strong-field QED
Greger Torgrimsson
In a previous paper we showed how higher-order strong-field-QED processes in long laser pulses can be approximated by multiplying sequences of "strong-field Mueller matrices". We o…
Discrete worldline instantons
Christian Schneider, Greger Torgrimsson, Ralf Schützhold
The semiclassical approximation of the worldline path integral is a powerful tool to study nonperturbative electron-positron pair creation in spacetime-dependent background fields.…
The worldline approach to helicity flip in plane waves
Anton Ilderton, Greger Torgrimsson
We apply worldline methods to the study of vacuum polarisation effects in plane wave backgrounds, in both scalar and spinor QED. We calculate helicity-flip probabilities to one loo…
Critical Schwinger pair production
Holger Gies, Greger Torgrimsson
We investigate Schwinger pair production in spatially inhomogeneous electric backgrounds. A critical point for the onset of pair production can be approached by fields that margina…
Scattered wave functions and worldline instantons for particle production in curved spacetime
Philip Semrén, Greger Torgrimsson
We study the production of spin- particle-antiparticle pairs in curved spacetimes with nontrivial dependence on more than one coordinate. To this end, we develop two complemen…
Thermally versus dynamically assisted Schwinger pair production
Greger Torgrimsson
We study electron-positron pair production by the combination of a strong, constant electric field and a thermal background. We show that this process is similar to dynamically ass…
Nonperturbative pair production in interpolating fields
Anton Ilderton, Greger Torgrimsson, Jonatan WÃ¥rdh
We compare the effects of timelike, lightlike and spacelike one-dimensional inhomogeneities on the probability of nonperturbative pair production in strong fields. Using interpolat…
Radiation reaction in strong field QED
Anton Ilderton, Greger Torgrimsson
We derive radiation reaction from QED in a strong background field. We identify, in general, the diagrams and processes contributing to recoil effects in the average momentum of a…
Critical Schwinger pair production II - universality in the deeply critical regime
Holger Gies, Greger Torgrimsson
We study electron-positron pair production by spatially inhomogeneous electric fields. Depending on the localization of the field, a critical point (critical surface) exists in the…
Photon polarisation in light-by-light scattering: finite size effects
Victor Dinu, Tom Heinzl, Anton Ilderton +2
We derive a simple expression for the photon helicity and polarisation-flip probabilities in arbitrary background fields, in the low energy regime. Taking the background to model a…
Nonlinear trident using WKB and worldline instantons
Gianluca Degli Esposti, Greger Torgrimsson
We consider nonlinear trident, , in various electric background fields. This…
Radiation reaction from QED: lightfront perturbation theory in a plane wave background
Anton Ilderton, Greger Torgrimsson
We derive dynamical, real time radiation reaction effects from lightfront QED. Combining the Hamiltonian formalism with a plane wave background field, the calculation is performed…
Ellipticity induced in vacuum birefringence
Greger Torgrimsson
We consider signals of photon-photon scattering in laser-based, low energy experiments. In particular, we consider the ellipticity induced on a probe beam by a strong background fi…
Scattering in plane-wave backgrounds: infra-red effects and pole structure
Anton Ilderton, Greger Torgrimsson
We consider two aspects of scattering in strong plane wave backgrounds. First, we show that the infra-red divergences in elastic scattering depend on the structure of the backgroun…
Pair production from residues of complex worldline instantons
Anton Ilderton, Greger Torgrimsson, Jonatan WÃ¥rdh
We study nonperturbative pair production in electric fields with lightlike inhomogeneities, using complex worldline instantons. We show that the instanton contribution to the pair…
Resummation of the expansion for nonlinear pair production
Greger Torgrimsson
We show how to resum the Furry-picture expansion in order to take quantum radiation reaction and spin transition into account in the nonlinear trident process in (pulsed) plan…