Related papers: Magnetically-enhanced open string pair production
We study the Schwinger mechanism for the pair production of fermions in the presence of an arbitrary time-dependent background electric field E(t) by directly evaluating the path integral. We obtain an exact non-perturbative result for the…
Method for computing scattering amplitudes of open strings with Dirichlet boundary on one end and Neumann boundary condition on the other is described. Vertex operator for these states are constructed using twist fields which have been…
This thesis describes an attempt to write down covariant actions for coincident D-branes using so-called boundary fermions instead of matrices to describe the non-abelian fields. These fermions can be thought of as Chan-Paton degrees of…
We study particle and chirality production from the vacuum in the presence of a slow strong parallel electromagnetic field superimposed by a fast weak perturbative electromagnetic field. We derive an analytical formula for the particle and…
In this thesis we discuss some nonperturbative and noncommutative aspects of string theory. We present low-energy background field solutions corresponding to various D-branes (and their bound states) and intersecting branes in flat and…
Using the boundary state formalism we study a moving D$p$-brane in a partially compact spacetime in the presence of the background fields: Kalb-Ramond $B_{\mu\nu}$, a U(1) gauge field $A_{\alpha}$ and the tachyon field. The boundary state…
A D5 brane winding around a stack of D3 branes can be used as a model of persistent current in a thin superconducting ring, with the number N of D3s corresponding to the number of transverse channels in the ring. We consider, in the large N…
The bound-free channel of electron-positron pair production by a highly charged bare ion in the presence of a strong constant crossed electromagnetic field is studied. To calculate the pair production rate, two different methods are applied…
We study particle - antiparticle pair production under action of a strong time dependent space homogeneous electric field at the presence of a collinear constant magnetic field. We derive the kinetic equation for a such field configuration…
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 marginally provide sufficient electrostatic energy for an off-shell…
The process of coherent creation of particle - hole excitations by an electric field in graphene is quantitatively described beyond linear response. We calculate the evolution of current density, number of pairs and energy in ballistic…
We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the…
We discuss the direct production of light stringy states. Those states correspond to the lightest stringy excitations localized at the intersection of two D-brane stacks and their mass can be parametrically smaller than the string scale.…
Electromagnetic plane waves provide examples of time-dependent open string backgrounds free of $\alpha'$ corrections. The solvable case of open strings in a quadrupolar wave front, analogous to pp-waves for closed strings, is discussed. In…
Recent studies of Schwinger pair production have demonstrated that the asymptotic particle spectrum is extremely sensitive to the applied field profile. We extend the idea of the dynamically assisted Schwinger effect from single pulse…
A recently proposed \ell=\infty field theory model of tachyon dynamics for unstable bosonic D-branes has been shown to arise as the two-derivative truncation of (boundary)-string field theory. Using an \ell\to \infty limit appropriate to…
We study the pair production of open strings in constant electric fields, using a general framework which encodes both relativistic string theory and generic linearly extended systems as well. In the relativistically invariant case we…
In this lecture I will review the present status of inflation within string-based brane-world scenarios. The idea is to start from a supersymmetric configuration with two parallel static Dp-branes, and slightly break the supersymmetry…
We investigate the Schwinger pair creation process in the context of gravitational models with the back reaction of the electric field included in the geometry. The background is also an exact solution of type II superstring theory, where…
We argue that gravitational interactions between open strings ending on D3-branes are largely shaped by the D3-branes' backreaction. To this end we consider classical open strings coupled to general relativity in Poincare AdS5 backgrounds.…