Boundary State Formalism Research Articles

Thermodynamics and tachyon condensation of the dressed-dynamical unstable Dp-branes

Using the boundary state formalism and thermo field dynamics approach, we study a Dp-brane at finite temperature in which the background Kalb–Ramond field, a U(1) gauge potential, and tachyon field are turned on together with a general tangential dynamics. The thermal entropy of the brane will be studied. In addition, the behavior of the entropy after the tachyon condensation process will be investigated and some thermodynamic interpretations will be extracted.

Pair production of the open superstrings from the parallel-dressed D3-branes in the compact spacetime

We employ the boundary state formalism to compute the pair creation rate of the open superstrings from the interaction of two parallel D3-branes. The branes live in the partially compact spacetime. In addition, they have been dressed with the internal gauge potentials and the Kalb–Ramond field.

Pair creation of open strings between the unstable-dressed Dp-branes

In this paper, we study the open string pair production via the interaction of two parallel D[Formula: see text]-branes. The branes have been dressed by the Kalb–Ramond field, a specific [Formula: see text] gauge potential and a tachyon field of the open string spectrum. We shall apply the boundary state formalism, in the context of the bosonic string theory.

Effective action of a dynamical Dp-brane with background fluxes

We shall construct the Dirac-Born-Infeld like and the Wess–Zumino like actions for a dynamical Dp-brane with the U(1) gauge potential and the Kalb–Ramond background field. The brane dynamics simultaneously has both tangential and transverse components. Our calculations will be in the context of the type II superstring theory, via the boundary state formalism.

Surface/state correspondence and bulk local operators in pp-wave holography

We apply the surface/state correspondence proposal of Miyaji et al. to IIB pp-waves and propose that the bulk local operators should be instantonic D-branes. In line with ordinary AdS/CFT correspondence, the bulk local operators in pp-waves also create a hole, or a boundary, in the dual gauge theory as pointed out by H. Verlinde, and by Y. Nakayama and H. Ooguri. We also present simple calculations which illustrate how to extract the spacetime metric of pp-waves from instantonic D-branes in boundary state formalism.

Moving fractional branes with background fields: Interaction and tachyon condensation

We calculate the bosonic boundary state corresponding to a moving fractional D$p$-brane in a partially orbifoldized spacetime $\mathbb{R}^{1, d-5} \times\mathbb{C}^{2}/\mathbb{Z}_{2}$ in the presence of the Kalb-Ramond field, the $U(1)$ gauge potential and the tachyon field. Using this boundary state we obtain interaction amplitude of two parallel moving D$p$-branes with the above background fields. Various properties of the interaction will be investigated. Besides, we study effects of the tachyon condensation on a moving fractional D$p$-brane with the above background fields through the boundary state formalism.

Resistance of a rotating-moving brane with background fields against collapse

Using the boundary state formalism we investigate the effect of tachyon condensation process on a rotating and moving Dp-brane with various background fields in the bosonic string theory. The rotation and motion are inside the brane volume. We demonstrate that some specific rotations and/or motions can preserve the brane from instability and collapse.

Tachyon condensation on a nonstationaryDp-brane with background fields in superstring theory

Using the boundary state formalism we obtain the partition function corresponding to a dynamical (rotating-moving) D$p$-brane in the presence of electromagnetic and tachyonic background fields in the superstring theory. The instability of such D$p$-brane due to the tachyon condensation is investigated.

Rotating-moving D-branes with background fields in superstring theory

Using the boundary state formalism we study rotating and moving D$p$-branes in the presence of the following background fields: Kalb-Ramond, $U(1)$ gauge potential and the tachyon field. The rotation and motion are in the brane volumes. The interaction amplitude of two D$p$-branes will be studied, and specially contribution of the superstring massless modes will be segregated. Because of the tachyon fields, rotations and velocities of the branes, the behavior of the interaction amplitude reveals obvious differences from what is conventional.

Rectangular amplitudes, conformal blocks, and applications to loop models

In this paper we continue the investigation of partition functions of critical systems on a rectangle initiated in [R. Bondesan, et al., Nucl. Phys. B 862 (2012) 553–575]. Here we develop a general formalism of rectangle boundary states using conformal field theory, adapted to describe geometries supporting different boundary conditions. We discuss the computation of rectangular amplitudes and their modular properties, presenting explicit results for the case of free theories. In a second part of the paper we focus on applications to loop models, discussing in details lattice discretizations using both numerical and analytical calculations. These results allow to interpret geometrically conformal blocks, and as an application we derive new probability formulas for self-avoiding walks.

Interaction of moving branes with background massless and tachyon fields in superstring theory

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 enables us to obtain interaction amplitude of two branes with above background fields. The branes are parallel or perpendicular to each other. Presence of the background fields, compactification of some directions of the spacetime, motion of the branes and arbitrariness of the branes' dimensions give a general feature to the system. Due to the tachyon fields and velocities of the branes, the behavior of the interaction amplitude reveals obvious differences from what is conventional.

Two Moving-Angled 1-Branes with Electric Fields in a Partially Compact Spacetime

In this article we consider two $m1$-branes at angle in the presence of the background electric fields, in a partially compact spacetime. The branes have motions along a common direction that is perpendicular to both of them. Using the boundary state formalism, we calculate their interaction amplitude. Some special cases of this interaction will be studied in detail.

One-point functions in massive integrable QFT with boundaries

We consider the expectation value of a local operator on a strip with non-trivial boundaries in 1+1 dimensional massive integrable QFT. Using finite volume regularisation in the crossed channel and extending the boundary state formalism to the finite volume case we give a series expansion for the one-point function in terms of the exact form factors of the theory. The truncated series is compared with the numerical results of the truncated conformal space approach in the scaling Lee-Yang model. We discuss the relevance of our results to quantum quench problems.

Issues on magnon reflection

Two questions related to reflections of magnons in AdS/CFT are discussed: namely the problem of explaining the (physical) poles of the reflection amplitudes using Landau type diagrams and the generalization of the Ghoshal–Zamolodchikov boundary state formalism to magnon reflections.

One-loop masses of open-string scalar fields in string theory

In phenomenological models with D-branes, there are in general open-string massless scalar fields, in addition to closed-string massless moduli fields corresponding to the compactification. It is interesting to focus on the fate of such scalar fields in models with broken supersymmetry, because no symmetry forbids their masses. The one-loop effect may give non-zero masses to them, and in some cases mass squared may become negative, which means the radiative gauge symmetry breaking. In this article we investigate and propose a simple method for calculating the one-loop corrections using the boundary state formalism. There are two categories of massless open-string scalar fields. One consists the gauge potential fields corresponding to compactified directions, which can be understood as scalar fields in uncompactified space-time (related with Wilson line degrees of freedom). The other consists "gauge potential fields" corresponding to transverse directions of D-brane, which emerge as scalar fields in D-brane world-volume (related with brane moduli fields). The D-brane boundary states with constant backgrounds of these scalar fields are constructed, and one-loop scalar masses are calculated in the closed string picture. Explicit calculations are given in the following four concrete models: one D25-brane with a circle compactification in bosonic string theory, one D9-brane with a circle compactification in superstring theory, D3-branes at a supersymmetric C^3/Z_3 orbifold singularity, and a model of brane supersymmetry breaking with D3-branes and anti-D7-branes at a supersymmetric C^3/Z_3 orbifold singularity. We show that the sign of the mass squared has a strong correlation with the sign of the related open-string one-loop vacuum amplitude.

The Casimir effect in the boundary state formalism

The Casimir effect in the planar setting is described using the boundary state formalism, for general partially reflecting boundaries. It is expressed in terms of the low-energy degrees of freedom, which provides a large distance expansion valid for general interacting field theories provided there is a non-vanishing mass gap. The expansion is written in terms of the scattering amplitudes, and needs no ultraviolet renormalization. We also discuss the case when the quantum field has a nontrivial vacuum configuration.

COMMENTS ON D-BRANES ON ORBIFOLDS AND K-THEORY

We systematically revisit the description of D-branes on orbifolds and the classification of their charges via K-theory. We include enough details to make the results accessible to both physicists and mathematicians interested in these topics. The minimally charged branes predicted by K-theory in ℤN orbifolds with N odd are only BPS. We confirm this result using the boundary state formalism for ℤ3. For ℤN × ℤN orbifolds with N odd, in the untwisted case and with discrete torsion whose class is a generator of H3(ℤ/N × ℤ/N,ℤ), we show that the K-theory classification of charges agrees with the boundary state approach, largely developed by Gaberdiel and collaborators, including the types of representation on the Chan–Paton factors.

Supertubes in matrix model and DBI action

We show the equivalence between the supertube solutions with an arbitrary cross section in two different actions, the DBI action for the D2-brane and the matrix model action for the D0-branes. More precisely, the equivalence between the supertubes in the D2-brane picture and the D0-brane picture is shown in the boundary state formalism which is valid for all order in \alpha'. This is an application of the method using the infinitely many D0-branes and anti-D0-branes which was used to show other equivalence relations between two seemingly different D-brane systems, including the D-brane realization of the ADHM construction of instanton. We also apply this method to the superfunnel type solutions successfully.

Boundary one-point function, Casimir energy and boundary state formalism in [formula omitted] dimensional QFT

We consider quantum field theories with boundary on a codimension one hyperplane. Using 1 + 1 dimensional examples, we clarify the relation between three parameters characterizing one-point functions, finite size corrections to the ground state energy and the singularity structure of scattering amplitudes, respectively. We then develop the formalism of boundary states in general D + 1 spacetime dimensions and relate the cluster expansion of the boundary state to the correlation functions using reduction formulae. This allows us to derive the cluster expansion in terms of the boundary scattering amplitudes, and to give a derivation of the conjectured relations between the parameters in 1 + 1 dimensions, and their generalization to D + 1 dimensions. We use these results to express the large volume asymptotics of the Casimir effect in terms of the one-point functions or alternatively the singularity structure of the one-particle reflection factor, and for the case of vanishing one-particle couplings we give a complete proof of our previous result for the leading behaviour.

Fractional branes in non-compact type IIA orientifolds

We study fractional D-branes in the Type-IIA theory on a non-compact orientifold of the orbifold C^3/Z_3 in the boundary state formalism. We find that the fractional D0-branes of the orbifold theory become unstable due to the presence of a tachyon, while there is a stable D-instanton whose tachyon gets projected out. We propose that the D-instanton is obtained after tachyon condensation. We evidence this by calculating the Whitehead group of the Abelian category of objects corresponding to the boundary states as being isomorphic to Z_2.