Trident process in laser pulses

Abstract

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 important for a short pulse. For a long pulse we identify a term that gives the dominant contribution even if the intensity is only moderately high, a01, which is an experimentally important regime where the standard locally-constant-field (LCF) approximation cannot be used. We show that the spectrum has a richer structure at a0 ∼ 1, compared to the LCF regime a01. We study the convergence to LCF as a0 increases and how this convergence depends on the momentum of the initial electron. We also identify the terms that dominate at high energy.

Approximating higher-order nonlinear QED processes with first-order building blocks

“…In [7] we demonstrated that our gluing method indeed gives a good approximation for trident in a long pulse with a 0 ∼ 1 and linear polarization. Since the expressions presented above are valid for any field polarization, we will demonstrate this fact here for trident in a circularly polarized field, aðϕÞ ¼ a 0 ffiffi ffi 2 p fsinðϕÞ; cosðϕÞ; 0ge −ðϕ=T…”

“…In the following we compare the two-step part with the one-step terms, i.e., the rest of the probability. All the relevant definitions are given in [7]. As shown in [7], for a very short pulse (T ∼ 1), low to moderate intensity (a 0 ≲ 1), and "low" energy (b 0 ≲ 1), the exchange part of the one-step (i.e., the cross term between the two terms on the amplitude level that are related by exchanging the two identical particles in the final state) can be comparable to the other terms.…”

“…3 and 4 we show the two sections s 1 ¼ s 2 and s 2 ¼ s 3 for different values of a 0 and χ and for a long pulse with T ¼ 80. These plots contain curves for the six different contributions to the one-step part, as defined in [6,7]. However, here it is enough to note that P ex is the exchange term, which is negligible, and P 22→1 dir is a part of the one-step that can be obtained with our gluing method.…”

“…After the first photon emission the photon can decay via nonlinear Breit-Wheeler pair production [4,5] γ → e − þ e þ or the electron can emit a second photon. The first gives one part of the nonlinear trident process [6][7][8][9][10][11][12][13][14][15][16][17][18] e − → e − þ e − þ e þ , and the second gives one part of double nonlinear Compton scattering [19][20][21][22][23][24][25][26] e − → e − þ γ þ γ. Since all the processes we consider here are in general nonlinear in the interaction with the laser, we will drop "nonlinear" from here on.…”

The Role of Non-Pharmacological Treatment for Osteoporosis at Patients with High Plasmatic Concentration of ACTH

“…Depressive disorders and other kind of disorders associated to Cushing disease were: 13% of ACTH secretive pituitary tumor had a severe depression (mania, anxiety disorders, demoralization, irritable mood), quality of life of patients with Cushing's disease is compromised at 8% while 5% present a light depression and only 2.5% didn't present any symptoms of depression. [10,11,[13][14][15][16] The risk of depression at the Cushing disease patients is higher than the risk of this psychiatric manifestation at other pituitary affections. Symptoms noticed at Cushing patients were: psycho-emotional lability, physical and psychical asthenia, loss of initiative, inhibition, tendency of social isolation, amnesic difficulties, mania, psychosis, irritability, depressive ideation, panic attack, fatigue, anxiety, maladaptive personality [12,[17][18][19][20][21].…”