相关论文: On Minisuperspace Models of S-branes

The sigma models on projective superspaces CP^{N+M-1|N} with topological angle theta=pi mod 2pi flow to non-unitary, logarithmic conformal field theories in the low-energy limit. In this paper, we determine the exact spectrum of these…

We study a brane-antibrane system and a non-BPS D-brane in SU(2) WZW model. We first discuss the tachyon condensation using the vertex operator formalism and find the generation of codimension two D-branes after the condensation. Our result…

Within the braneworld paradigm the tachyonic scalar field has been used to generate models that attempt to solve some of the open problems that physics faces nowadays, both in cosmology and high energy physics as well. When these field…

We uncover new non-supersymmetric boundary conditions in 10- and 11-dimensional supergravity whereby spacetime ends on a smeared distribution of D- and M-branes respectively. For example, we find a solution of type IIB supergravity where…

We evaluate various disk level four-point functions involving the massless scalar and tachyon vertex operators in the presence of background B-flux in superstring theory. By studying these amplitudes in specific limits, we find couplings of…

In this thesis we review the fundamental framework of boundary string field theory (BSFT) and apply it to the tachyon condensation on non-BPS systems in the superstring theory. The boundary string field theory can be regarded as a natural…

When p-dimensional branes annihilate with antibranes in the early universe, as in brane-antibrane inflation, stable (p-2)-dimensional branes can appear in the final state. We reexamine the possibility that one of these (p-2)-branes could be…

We discuss theories in which the standard-model particles are localized on a brane embedded in space-time with large compact extra dimensions, whereas gravity propagates in the bulk. In addition to the ground state corresponding to a…

The worldvolume field equations of M-branes and D-branes are known to admit p-brane soliton solutions. These solitons are shown to saturate a BPS-type bound on their p-volume tensions, which are expressed in terms of central charges that…

Extra-dimensional scenarios have become widespread among particle and gravitational theories of physics to address several outstanding problems, including cosmic acceleration, the weak hierarchy problem, and the quantization of gravity. In…

We study N=1 super Liouville theory on worldsheets with and without boundary. Some basic correlation functions on a sphere or a disc are obtained using the properties of degenerate representations of superconformal algebra. Boundary states…

We investigate the tachyon condensation process in the effective theory with non-vanishing minimum potential and its implications to cosmology. It is shown that the tachyon condensation on an unstable three-brane described by this modified…

Considering that the effective theory of closed string tachyons can have worldsheet supersymmetry, as shown by Vafa, we study a worldline supersymmetric action in a FRW background, whose superpotential originates a tachyon scalar potential.…

It is well-known that the momentum spectra of particles confined to finite spatial volumes deviate from the continuous spectra used for unconfined particles. In this article, we consider real scalar particles confined to finite volumes with…

We consider how the time-dependent decay process of an unstable D-brane should be described in the full (quantum) open-closed string theory. It is argued that the system, starting from the unstable D-brane configuration, will evolve in time…

Many theoretically well-motivated extensions of the Standard Model contain heavy pseudoscalars that couple to hypercharge topological density. The cosmological dynamics of such hypercharge axions could, under certain conditions, lead to…

We collect some arguments for treating a D-brane with overcritical electric field as a well-posed initial condition for a D-brane decay. Within the field theoretical toy model of Minahan and Zwiebach we give an estimate for the condensates…

Braneworld models may yield interesting effects ranging from high-energy physics to cosmology, or even some low-energy physics. Their mode structure modifies standard results in these physical realms that can be tested and used to set…

We study three-dimensional superconformal field theories on wrapped M5-branes. Applying the gauge/gravity duality and the recently proposed 3d-3d relation, we deduce quantitative predictions for the perturbative free energy of a…

Cosmological solutions of the beta function equations for the background fields of the closed bosonic string are investigated at the one-loop level. Following recent work of Kostelecky and Perry, it is assumed that the spatial sections of…