Brane-antibrane Systems Research Articles

Supergravity p -branes with scalar charge

Standard dilatonic supergravity $p$-branes have scalar charges that are not independent parameters, but are determined by the brane tension and Page charges. This feature can be traced to the no-hair theorem in the four-dimensional Einstein-scalar gravity, implying that more general solutions with independent scalar charges can have naked singularities. Since singular branes are also of interest as tentative classical counterparts of unstable tachyonic branes and/or brane-antibrane systems, it is worth investigating branes with independent scalar charges in more detail. Here we study singular branes associated with the Fisher-Janis-Newman-Winicour solution of four-dimensional gravity. In the case of codimension three, we also construct singular branes endowed with a Zipoy-Voorhees-type oblateness parameter. It is expected that such branes will not be supersymmetric in the string theory. We demonstrate this in the special case of NS5-branes of type II theory. We analyze geodesics and test scalar perturbations of new solutions focusing on possible quantum healing of classical singularities.

Cosmology from confinement?

We describe a class of holographic models that may describe the physics of certain four-dimensional big-bang/big-crunch cosmologies. The construction involves a pair of 3D Euclidean holographic CFTs each on a homogeneous and isotropic space M coupled at either end of an interval ℐ to a Euclidean 4D CFT on M × ℐ with many fewer local degrees of freedom. We argue that in some cases, when the size of M is much greater than the length of ℐ, the theory flows to a confining three-dimensional field theory on M in the infrared, and this is reflected in the dual description by the asymptotically AdS spacetimes dual to the two 3D CFTs joining up in the IR to give a Euclidean wormhole. The Euclidean construction can be reinterpreted as generating a state of the Lorentzian 4D CFT on M × time whose dual includes the physics of a big-bang/big-crunch cosmology. When M is ℝ3, we can alternatively analytically continue one of the ℝ3 directions to get an eternally traversable four-dimensional planar wormhole. We suggest explicit microscopic examples where the 4D CFT is mathcal{N} = 4 SYM theory and the 3D CFTs are superconformal field theories with opposite orientation. In this case, the two geometries dual to the pair of 3D SCFTs can be understood as a geometrical version of a brane-antibrane pair, and the tendency of the geometries to connect up is related to the standard instability of brane-antibrane systems.

Brane-antibrane Systems at Finite Temperature and Phase Transition near the Hagedorn Temperature(Thermal Quantum Field Theories and Their Applications)

Brane-antibrane Systems at Finite Temperature and Phase Transition near the Hagedorn Temperature(Thermal Quantum Field Theories and Their Applications)

Confinement and nonperturbative tachyons in brane-antibrane systems

We present a worldvolume effective action suitable for the study of the confined phase of a (Dp,Dp) system at weak coupling. We identify the mechanism by which the fundamental string arises from this action as a confined electric flux string when the Dp and the Dp annihilate. We construct an explicit dual action, more suitable for the study of the strong coupling regime, and show that it realizes a generalized Higgs-Stueckelberg phase for the (relative) (p-2)-form field dual to the (overall) Born-Infeld vector. This is the mechanism put forward by Yi and collaborators based on duality arguments in order to explain the breaking of the overall U(1) gauge group at strong coupling. Indeed, in our dual description the Goldstone boson is a (p-3) form magnetically charged with respect to the overall Born-Infeld vector field. This indicates that the condensing tachyonic objects originate from open D(p-2)-branes stretched between the brane and the antibrane. Our results provide an explicit realization of the breaking of the overall U(1) gauge group perturbatively, in a way consistent with the duality symmetries of string theory.

Enhanced symmetries of gauge theory and resolving the spectrum of local operators

Enhanced global non-Abelian symmetries at zero coupling in Yang Mills theory play an important role in diagonalizing the two-point functions of multimatrix operators. Generalized Casimirs constructed from the iterated commutator action of these enhanced symmetries resolve all the multiplicity labels of the bases of matrix operators which diagonalize the two-point function. For the case of $U(N)$ gauge theory with a single complex matrix in the adjoint of the gauge group we have a $U(N{)}^{\ifmmode\times\else\texttimes\fi{}4}$ global symmetry of the scaling operator at zero coupling. Different choices of commuting sets of Casimirs, for the case of a complex matrix, lead to the restricted Schur basis previously studied in connection with string excitations of giant gravitons and the Brauer basis studied in connection with brane-antibrane systems. More generally these remarks can be extended to the diagonalization for any global symmetry group $G$. Schur-Weyl duality plays a central role in connecting the enhanced symmetries and the diagonal bases.

Higher derivative corrections to Wess-Zumino action of brane-antibrane systems

By explicit calculation, we show that the expansion of the disk level S-matrix element of one RR field, two open string tachyons and one gauge field that has been recently found corresponds to the derivative expansion of the Wess-Zumino action of D-brane-anti-D-brane systems.

On Wess–Zumino terms of brane–antibrane systems

We calculate the disk level S-matrix element of one closed string RR field, two open string tachyons and one gauge field in type II superstring theory. An expansion for the S-matrix element has been found that its four leading order terms are reproduced exactly by the symmetric trace tachyon DBI and the Wess–Zumino actions of D-brane–anti-D-brane systems. Using this consistency, we have also found the first higher derivative correction to the some of the WZ terms.

STABILITY OF BRANONIUM

We investigate the time-dependent behaviour of brane-antibrane orbital systems, mainly concentrating on the stability of the "Branonium" configuration.

QUANTUM DESCRIPTION FOR THE DECAY OF NSNS BRANE–ANTIBRANE SYSTEMS

The stringy description for the instabilities in the RR charged [Formula: see text] pairs is now well understood in terms of the open string tachyon condensation. The quantum interpretation presumably via the stringy description for the instabilities in the NSNS-charged [Formula: see text] and [Formula: see text] pairs in IIA/IIB theories, however, has not been fully established yet. This would be partly because of the absence (for the [Formula: see text] case) or our relatively poor understanding (for the [Formula: see text] case) of their world-volume (gauge theory) dynamics. In the present work, using the well-known quantum description for instabilities in the RR-charged [Formula: see text] systems and in the M-theory brane–antibrane systems and invoking appropriate string dualities, the stringy nature of the instabilities in the NSNS-charged [Formula: see text] and [Formula: see text] systems both at strong and at weak couplings has been uncovered. For the annihilations to string vacua, the quantum, stringy interpretations are simple extensions of Sen's conjecture for those in RR-charged brane–antibrane systems.

Black Hole Entropy and Superconformal Field Theories on Brane-Antibrane Systems

We obtain the enropy of Schwarzschild and charged black holes in D>4 from superconformal gases that live on p=10-D dimensional brane-antibrane systems wrapped on T^p. The preperties of the strongly coupled superconformal theories such as the appearance of hidden dimensions (for p=1,4) and fractional strings (for p=5) are crucial for our results. In all cases, the Schwarzschild radius is given by the transverse fluctuations of the branes and antibranes due to the finite temperature. We show that our results can be generalized to multicharged black holes.

Fayet–Iliopoulos terms in supergravity and cosmology

We clarify the structure of N = 1 supergravity in 1+3 dimensions with constant Fayet–Iliopoulos (FI) terms. The FI terms gξ induce non-vanishing R-charges for the fermions and the superpotential. Therefore the D-term inflation model in supergravity with constant FI terms has to be revisited. We present all corrections of order gξ/M2P to the classical supergravity action required by local supersymmetry and provide a gauge-anomaly-free version of the model. We also investigate the case of the so-called anomalous U(1) when a chiral superfield is shifted under U(1). In such a case, in the context of string theory, the FI terms originate from the derivative of the Kähler potential and they are inevitably field dependent. This raises an issue of stabilization of the relevant field in applications to cosmology. The recently suggested equivalence between the D-term strings and D-branes of type II theory shows that brane–anti-brane systems produce the FI terms in the effective 4d theory, with the Ramond–Ramond axion shifting under the U(1) symmetry. This connection gives the possibility to interpret many unknown properties of systems in the more familiar language of 4d supergravity D-terms, and vice versa. For instance, the shift of the axion field in both cases restricts the possible forms of the moduli-stabilizing superpotential. We provide some additional consistency checks of the correspondence of D-term strings to D-branes and show that instabilities of the two are closely related. Surviving cosmic D-strings of the type II theory may be potentially observed in the form of D-term strings of 4d supergravity. We study such string solutions of supergravity with constant FI terms with one half supersymmetry unbroken and explain some of the puzzling properties of the zero modes around cosmic strings, such as the difference between the numbers of fermionic and bosonic modes.

Finite temperature systems of brane-antibrane on a torus

In order to study the thermodynamic properties of brane-antibrane systems in the toroidal background, we compute the finite temperature effective potential of tachyon T in this system on the basis of boundary string field theory. We first consider the case that all the radii of the target space torus are about the string scale. If the Dp-antiDp pair is extended in all the non-compact directions, the sign of the coefficient of |T|^2 term of the potential changes slightly below the Hagedorn temperature. This means that a phase transition occurs near the Hagedorn temperature. On the other hand, if the Dp-antiDp pair is not extended in all the non-compact directions, the coefficient is kept negative, and thus a phase transition does not occur. Secondly, we consider the case that some of the radii of the target space torus are much larger than the string scale and investigate the behavior of the potential for each value of the radii and the total energy. If the Dp-antiDp pair is extended in all the non-compact directions, a phase transition occurs for large enough total energy.

A matrix model dual of type 0B string theory in two dimensions

We propose that type 0B string theory in two dimensions admits a dual description in terms of a one dimensional bosonic matrix model of a hermitian matrix. The potential in the matrix model is symmetric with respect to the parity-like Z_2 transformation of the matrix. The two sectors in the theory, namely the NSNS and RR scalar sectors correspond to two classes of operators in the matrix model, even and odd under the Z_2 symmetry respectively. We provide evidence that the matrix model successfully reconstructs the perturbative S-matrix of the string theory, and reproduces the closed string emission amplitude from unstable D-branes. Following recent work in two dimensional bosonic string, we argue that the matrix model can be identified with the theory describing N unstable D0-branes in type 0B theory. We also argue that type 0A theory is described in terms of the quantum mechanics of brane-antibrane systems.

Real-time D-brane condensation

Unstable D-branes or brane–antibrane systems can decay to lower-dimensional branes. In the effective field theory description, the final state branes are defects in the tachyon field which describes the initial instability. We study the dynamical formation of codimension one defects (kinks) using Sen's ansatz for the tachyon Lagrangian. It is shown that the slope of the kink diverges within a finite amount of time after the tachyon starts to roll. We discuss the relevance for reheating after brane–antibrane inflation.

Brane–anti-brane systems interaction under tachyon condensation

The interaction between a parallel brane–anti-brane and brane–anti-brane is investigated by regarding the brane–anti-brane pair as a kink or anti-kink type tachyon condensed state. As the kink-type tachyon condensed state is known as a non-BPS brane we expand the Lagrangian of tachyon effective field theory to the quadratic order in the off-diagonal fluctuation and then use the zeta-function regularization and Schwinger perturbative formula to evaluate the interaction within a kink–kink or a kink–anti-kink. The results show that while the kink and kink has repulsive force the kink and anti-kink has attractive force and may annihilate by each other. We, therefore, evaluate the free energy at finite temperature and determine the critical temperature above which the stable state of kink–anti-kink system may be found.

Supergravity Approach to Tachyon Potential in Brane-Antibrane Systems

Using an exact supergravity solution representing the Dp-\bar{Dp} system, it is demonstrated that one can construct a supergravity analogue of the tachyon potential. Remarkably, the (regularized) minimum value of the potential turns out to be V(T_{0})=-2m with m denoting the ADM mass of a single Dp-brane. This result, in a sense, appears to confirm that Sen's conjecture for the tachyon condensation on unstable D-branes is indeed correct although the analysis used here is semi-classical in nature and hence should be taken with some care. Also shown is the fact that the tachyon mass squared m^2_{T} (which has started out as being negative) can actually become positive definite and large as the tachyon rolls down toward the minimum of its potential. It indeed signals the possibility of successful condensation of the tachyon since it shows that near the minimum of its potential, tachyon can become heavy enough to disappear from the massless spectrum. Some cosmological implications of this tachyon potential in the context of ``rolling tachyons'' is also discussed.

Fluxbranes delaying brane–antibrane annihilation

By intersecting the RR charged D p – D p pair ( p=6,4,2,0) with the RR F7-brane and by intersecting the NSNS charged F1– F 1 and NS5– NS 5 pairs with the NSNS F6-branes, the possibility of stabilizing the brane–antibrane systems is considered. The behavior of the corresponding supergravity solutions indicates that the RR F7-brane content of the solution plays the role of keeping the brane and the antibrane from annihilating each other completely since the two-brane configuration structure still persists in the vanishing inter-brane distance limit of the supergravity solution. In terms of the stringy description, we interpret this as representing that the RR F7-brane “delays” the brane–antibrane annihilation process but only until this non-supersymmetric and hence unstable F7-brane itself decays. Then next, the behavior of the supergravity solutions representing F1– F 1 and NS5– NS 5 again for vanishing inter-brane separation reveals that as they approach, these “NS”-charged brane and antibrane always collide and annihilate irrespective of the presence or the absence of the NSNS F6-brane. And we have essentially attributed this to the absence of (open) stringy description of the instability in the “NS”-charged case. This interpretation may provide a resolution to the contrasting features between the instability of “R”-charged brane–antibrane systems and that of “NS”-charged ones. Certainly, however, it poses another puzzle that in the “NS”-charged case, the quantum entity, that should take over the semi-classical instability as the inter-brane distance gets smaller, is missing. This is rather an embarrassing state of affair that needs to be treated with great care.

Brane-antibrane systems at finite temperature and phase transition near the Hagedron temperature

Brane-antibrane systems at finite temperature and phase transition near the Hagedron temperature

Brane-Antibrane Systems at Finite Temperature and Phase Transition near the Hagedorn Temperature

In order to study the thermodynamic properties of brane-antibrane systems, we compute the finite temperature effective potential of tachyon T in this system on the basis of boundary string field theory. At low temperature, the minimum of the potential shifts towards T=0 as the temperature increases. In the D9-antiD9 case, the sign of the coefficient of |T|^2 term of the potential changes slightly below the Hagedorn temperature. This means that a phase transition occurs near the Hagedorn temperature. On the other hand, the coefficient is kept negative in the Dp-antiDp case with p <= 8, and thus a phase transition does not occur. This leads us to the conclusion that only a D9-antiD9 pair and no other (lower dimensional) brane-antibrane pairs are created near the Hagedorn temperature. We also discuss a phase transition in NS9B-antiNS9B case as a model of the Hagedorn transition of closed strings.

Supersymmetric Brane-Antibrane Systems: Matrix Model Description, Stability and Decoupling Limits

After reviewing the supertubes and super brane-antibrane systems in the context of matrix model, we look for more general higher-dimensional configurations. For D3-bar{D3}, we find a non-trivial configuration with E cdot B not equal to 0 and describe the worldvolume gauge theory. We present the string probe of D3-bar{D3} system and study the decoupling limits leading to either noncommutative Super-Yang-Mills or NCOS theories with eight supercharges.