Breit-Wheeler process in very short electromagnetic pulses

Abstract

The generalized Breit-Wheeler process, i.e. the emission of $e^+e^-$ pairs off a probe photon propagating through a polarized short-pulsed electromagnetic (e.g.\ laser) wave field, is analyzed. We show that the production probability is determined by the interplay of two dynamical effects. The first one is related to the shape and duration of the pulse and the second one is the non-linear dynamics of the interaction of $e^\pm$ with the strong electromagnetic field. The first effect manifests itself most clearly in the weak-field regime, where the small field intensity is compensated by the rapid variation of the electromagnetic field in a limited space-time region, which intensifies the few-photon events and can enhance the production probability by orders of magnitude compared to an infinitely long pulse. Therefore, short pulses may be considered as a powerful amplifier. The non-linear dynamics in the multi-photon Breit-Wheeler regime plays a decisive role at large field intensities, where effects of the pulse shape and duration are less important. In the transition regime, both effects must be taken into account simultaneously. We provide suitable expressions for the $e^+e^-$ production probability for kinematic regions which can be used in transport codes.Comment: 32 pages, 15 figure

Electron-positron pair production in a bifrequent oscillating electric field

“…In parallel, various mechanisms for compensating the suppression associated with the spontaneous creation of electron-positron pairs from the vacuum have been put forward [19][20][21][22][23][24][25][26][27][28][29][30]. Some of them have been motivated by the fact that pair production by multiphoton absorption has been observed using nonlinear Compton scattering [31].…”

Determination of the carrier envelope phase for short, circularly polarized laser pulses

“…The different aspect of e + e − pair creation in finite pulses was also analyzed in Refs. [25,[28][29][30]. Below, we will concentrate mainly on the effect of CEP, using the definitions of our Ref.…”

“…Below, we will concentrate mainly on the effect of CEP, using the definitions of our Ref. [25] In the following we use the widely employed the electromagnetic (e.m.) four-potential for a circularly polarized laser field in the axial gauge A µ = (0, A(φ)) with…”

“…We limit our discussion to circularly polarized pulses: First, because the case of linear laser polarization has been already analyzed in [17,19,20]. And second, the methods elaborated in [25,26] for quantum processes with circularly polarized finite laser pulses (by utilizing the generalized Bessel functions) allows to show the effect of the CEP on a transparent, almost qualitative level, which may be used as a powerful method for the CEP determination. Thus, we show that the azimuthal angle distributions of the emitted electron (positron) in the first case, and the recoil electron (emitted photon) in the second case are in fact very sensitive to a CEP variation and can be used to fix the CEP value.…”

Multi-photon regime of non-linear Breit-Wheeler and Compton processes in short linearly and circularly polarized laser pulses

“…A number of interesting and important effect of finite pulses related to the non-linear Compton (C) and BW processes are analyzed in Refs. [11][12][13][14][15][17][18][19][20][21][22][23][24][25] and [26][27][28][29][30][31][32][33][34][35] , respectively. The temporal pulse structure is expected to be important for short and ultrashort pulses.…”