Kaluza-Klein Monopole Research Articles

Dp-branes, NS5-branes and U-duality from nonabelian (2,0) theory with Lie 3-algebra

We derive the super Yang-Mills action of Dp-branes on a torus T^{p-4} from the nonabelian (2,0) theory with Lie 3-algebra. Our realization is based on Lie 3-algebra with pairs of Lorentzian metric generators. The resultant theory then has negative norm modes, but it results in a unitary theory by setting VEV's of these modes. This procedure corresponds to the torus compactification, therefore by taking a transformation which is equivalent to T-duality, the Dp-brane action is obtained. We also study type IIA/IIB NS5-brane and Kaluza-Klein monopole systems by taking other VEV assignments. Such various compactifications can be realized in the nonabelian (2,0) theory, since both longitudinal and transverse directions can be compactified, which is different from the BLG theory. We finally discuss U-duality among these branes, and show that most of the moduli parameters in U-duality group are recovered. Especially in D5-brane case, the whole U-duality relation is properly reproduced.

KK6 from M2 in BLG

We study the possibility that the Kaluza-Klein monopole (KK6) world-volume action may be obtained from the multiple membranes (M2) action which is described by BLG theory. We first point out that the infinite dimensional Lie 3-algebra based on the Nambu-Poisson structure could not only provide three dimensional manifolds to allow M5 from M2, which was studied by previous authors, but also provide five dimensional manifolds to allow KK6 from M2. We next present a possible way that the U(1) field on KK6 world-volume action could be produced form the gauge potential in BLG theory.

Topological charges inSL(2,R)covariant massive 11-dimensional and type IIB supergravity

In this paper we construct closed expressions that correspond to the topological charges of the various 1/2-BPS states of the maximal 10 and 11-dimensional supergravity theories. These expressions are related to the structure of the SUSY algebras in curved spacetimes. We mainly focus on IIB SUGRA and 11-dimensional SUGRA in a double M9-brane background, with an emphasis on the SL(2,R) multiplet structure of the charges and how these map between theories. This includes the charges corresponding to the multiplets of 7- and 9-branes in IIB. We find that examining the possible multiplet structures of the charges provides another tool for exploring the spectrum of BPS states that appear in these theories. As a prerequisite to constructing the charges we determine the field equations and multiplet structure of the 11-dimensional gauge potentials, extending previous results on the subject. The massive gauge transformations of the fields are also discussed. We also demonstrate how these massive gauge transformations are compatible with the construction of an SL(2,R) covariant kinetic term in the 11-dimensional Kaluza-Klein monopole worldvolume action.

M-BRANE BOUND STATES AND THE SUPERSYMMETRY OF BPS SOLUTIONS IN THE BAGGER–LAMBERT THEORY

We continue our study of BPS equations and supersymmetric configurations in the Bagger–Lambert (BL) theory. The superalgebra allows three different types of central extensions which correspond to compounds of various M-theory objects: M2-branes, M5-branes, gravity waves and Kaluza–Klein monopoles which intersect or have overlaps with the M2-branes whose dynamics is given by the BL action. As elementary objects they are all 1/2-BPS, and multiple intersections of n-branes generically break the supersymmetry into 1/2n, as it is well known. But a particular composite of M-branes can preserve from 1/16 up to 3/4 of the original [Formula: see text] supersymmetries as previously discovered. In this paper we provide the M-theory interpretation for various BPS equations, and also present explicit solutions to some 1/2-BPS equations.

Adding flavor toAdS4/CFT3

Aharony, Bergman, Jafferis, and Maldacena have proposed that the low-energy description of multiple M2-branes at a 4/k singularity is a (2+1)-dimensional = 6 supersymmetric U(Nc) × U(Nc) Chern-Simons matter theory, the ABJM theory. In the large-Nc limit, its holographic dual is supergravity in AdS4 × S7/k. We study various ways to add fields that transform in the fundamental representation of the gauge groups, i.e. flavor fields, to the ABJM theory. We work in a probe limit and perform analyses in both the supergravity and field theory descriptions. In the supergravity description we find a large class of supersymmetric embeddings of probe flavor branes. In the field theory description, we present a general method to determine the couplings of the flavor fields to the fields of the ABJM theory. We then study four examples in detail: codimension-zero = 3 supersymmetric flavor, described in supergravity by Kaluza-Klein monopoles or D6-branes; codimension-one = (0,6) supersymmetric chiral flavor, described by D8-branes; codimension-one = (3,3) supersymmetric non-chiral flavor, described by M5/D4-branes; codimension-two = 4 supersymmetric flavor, described by M2/D2-branes. Finally we discuss special physical equivalences between brane embeddings in M-theory, and their interpretation in the field theory description.

Large D-instanton effects in string theory

By reduction along the time direction, black holes in 4 dimensions yield instantons in 3 dimensions. Each of these instantons contributes individually at order $\exp(-|Q|/g_s)$ to certain protected couplings in the three-dimensional effective action, but the number of distinct instantons is expected to be equal (or comparable) to the number of black hole micro-states, i.e. of order $\exp(Q^2)$. The same phenomenon also occurs for certain protected couplings in four dimensions, such as the hypermultiplet metric in type II string theories compactified on a Calabi-Yau threefold. In either case, the D-instanton series is therefore asymptotic, much like the perturbative expansion in any quantum field theory. By using a Borel-type resummation method, adapted to the Gaussian growth of the D-instanton series, we find that the total D-instanton sum has an inherent ambiguity of order $\exp(-1/g_s^2)$. We further suggest that this ambiguity can be lifted by including Kaluza-Klein monopole or NS5-brane instantons.

Dynamics of intersecting brane systems — Classification and their applications

We present dynamical intersecting brane solutions in higher-dimensional gravitational theory coupled to dilaton and several forms. Assuming the forms of metric, form fields, and dilaton field, we give a complete classification of dynamical intersecting brane solutions with/without M-waves and Kaluza-Klein monopoles in eleven-dimensional supergravity. We apply these solutions to cosmology and black holes. It is shown that these give FRW cosmological solutions and in some cases Lorentz invariance is broken in our world. If we regard the bulk space as our universe, we may interpret them as black holes in the expanding universe. We also discuss lower-dimensional effective theories and point out naive effective theories may give us some solutions which are inconsistent with the higher-dimensional Einstein equations.

5D fuzzball geometries and 4D polar states

We analyze the map between a class of `fuzzball' solutions in five dimensions and four-dimensional multicentered solutions under the 4D-5D connection, and interpret the resulting configurations in the framework of Denef and Moore [1]. In five dimensions, we consider Kaluza-Klein monopole supertubes with circular profile which represent microstates of a small black ring. The resulting four-dimensional configurations are, in a suitable duality frame, polar states consisting of stacks of D6 and anti-D6 branes with flux. We argue that these four-dimensional configurations represent zero-entropy constituents of a 2-centered configuration where one of the centers is a small black hole. We also discuss how spectral flow transformations in five dimensions, leading to configurations with momentum, give rise to four-dimensional D6 anti-D6 polar configurations with different flux distributions at the centers.

Topological BPS charges in 10- and 11-dimensional supergravity

In this thesis we construct closed expressions that correspond to the topological charges of the various BPS branes of the IIA, IIB and $D=11$ supergravity theories. These expressions are related to the structure of the SUSY algebras in curved spacetimes. We consider charges for all the M-, NS- and D-branes as well as the Kaluza-Klein monopoles. Additionally we consider the $SL(2,\mathbb{R})$ symmetry that exists in the IIB theory and $D=11$ theory in a double M9-brane background, and determine the charges for the remaining branes that fill up the $SL(2,\mathbb{R})$ multiplets. These include the charges corresponding to the multiplets of 7 and 9-branes in IIB as well as several new types of branes in $D=11$. We find that examining the possible multiplet structures of the charges provides another tool for exploring the spectrum of BPS branes that appear in these theories. Furthermore, we demonstrate how these charges map between theories. As a prerequisite to constructing some of the charges we determine the field equations and multiplet structure of the $D=11$ gauge potentials, extending previous results on the subject. The massive gauge transformations of the fields are also discussed, and we demonstrate how they are compatible with the construction of an $SL(2,\mathbb{R})$ covariant kinetic term in the $D=11$ Kaluza-Klein monopole worldvolume action.

Moduli fixing andTduality in type II brane gas models

We consider a compactification with a six-dimensional torus in the type II brane gas models. We show that the dilaton and the scale of each cycle of the internal space are fixed in the presence of NS5-branes and Kaluza-Klein monopoles as well as D-branes with the gauge fields. We can construct various models that lead to fixed moduli by using $T$-duality transformations.

Near-horizon microstates of the D1-D5-P black hole

We construct probe solutions in the attractor background of the five-dimensional D1-D5-P black hole which represent near-horizon microstates in the limit of large D1-charge. These generalize the corresponding solutions considered by Gaiotto, Strominger and Yin for the 4-dimensional D0-D4 black hole. Using U-duality and a 4D-5D connection, we argue that the relevant configurations are bound states of D1-branes that have expanded through the Myers effect to form a Kaluza-Klein monopole wrapping the black hole horizon. We show that these branes experience a magnetic field on their moduli space, and that the degeneracy of lowest Landau levels reproduces the Bekenstein-Hawking entropy.

Topological T-duality and Kaluza-Klein monopoles

We study topological T-duality for spaces with a semi-free $S^1-$action with isolated fixed points. Physically, these correspond to spacetimes containing Kaluza-Klein monopoles. We demonstrate that the physical dyonic coordinate of such spaces has an analogue in our formalism. By analogy with the Dirac monopole, we study these spaces as gerbes. We study the effect of Topological T-duality on these gerbes.

Non-supersymmetric microstates of the D1-D5-KK system

We construct a discrete family of smooth non-supersymmetric three charge geometries carrying D1 brane, D5 brane and Kaluza-Klein monopole charges in Type IIB supergravity compactified on a six-torus, which can be interpreted as the geometric description of some special states of the brane system. These solutions are asymptotically flat in four dimensions, and generalise previous supersymmetric solutions. The solutions have a qualitatively similar structure to previous non-supersymmetric smooth solutions carrying D1 and D5 brane charges in five dimensions, and indeed can be viewed as the five-dimensional system placed at the core of a Kaluza-Klein monopole. The geometries are smooth, free of horizons and do not have closed timelike curves. One notable difference from the five-dimensional case is that the four-dimensional geometry has no ergoregion.

Killing superalgebra deformations of ten-dimensional supergravity backgrounds

We explore Lie superalgebra deformations of the Killing superalgebras of some ten-dimensional supergravity backgrounds. We prove the rigidity of the Poincaré superalgebras in types I, IIA and IIB, as well as of the Killing superalgebra of the Freund–Rubin vacuum of type IIB supergravity. We also prove rigidity of the Killing superalgebras of the NS5-, D0-, D3-, D4- and D5-branes, whereas we exhibit the possible deformations of the D1-, D2-, D6- and D7-brane Killing superalgebras, as well as of that of the type II fundamental string solutions. We relate the superalgebra deformations of the D2- and D6-branes to those of the (delocalized) M2-brane and the Kaluza–Klein monopole, respectively. The good behaviour under Kaluza–Klein reduction suggests that the deformed superalgebras ought to have a geometric interpretation.

Deformations of M-theory Killing superalgebras

We classify the Lie superalgebra deformations of the Killing superalgebras of some M-theory backgrounds. We show that the Killing superalgebras of the Minkowski, Freund–Rubin and M5-brane backgrounds are rigid, whereas the ones for the M-wave, the Kaluza–Klein monopole and the M2-brane admit deformations, which we give explicitly.

AdS4flux vacua in type II superstrings and their domain-wall solutions

We investigate the emergence of supersymmetric negative-vacuum-energy ground states in four dimensions. First, we rely on the analysis of the effective superpotential, which depends on the background fluxes of the internal manifold, or equivalently has its origin in the underlying gauged supergravity. Four-dimensional, supersymmetric anti-de Sitter vacua with all moduli stabilized appear when appropriate Ramond and Neveu-Schwarz fluxes are introduced in IIA. Geometric fluxes are not necessary. Then the whole setup is analyzed from the perspective of the sources, namely D/NS-branes or Kaluza-Klein monopoles. Orientifold planes are also required for tadpole cancellation. The solutions found in four dimensions correspond to domain walls interpolating between AdS4 and flat spacetime. The various consistency conditions (equations of motion, Bianchi identities and tadpole cancellation conditions) are always satisfied, albeit with source terms. We also speculate on the possibility of assigning (formal) entropies to AdS4 flux vacua via the corresponding dual brane systems.

Nondecoupling of Maximal Supergravity from the Superstring

We consider the conditions necessary for obtaining perturbative maximal supergravity in d dimensions as a decoupling limit of type II superstring theory compactified on a (10-d) torus. For dimensions d=2 and d=3, it is possible to define a limit in which the only finite-mass states are the 256 massless states of maximal supergravity. However, in dimensions d>or=4, there are infinite towers of additional massless and finite-mass states. These correspond to Kaluza-Klein charges, wound strings, Kaluza-Klein monopoles, or branes wrapping around cycles of the toroidal extra dimensions. We conclude that perturbative supergravity cannot be decoupled from string theory in dimensions>or=4. In particular, we conjecture that pure N=8 supergravity in four dimensions is in the Swampland.

Beyond twisted tori

Exploiting the fact that Kaluza–Klein monopoles and the associated generalized orbifold planes are sources for geometrical fluxes, ω, we show that the standard constraint ωω=0, valid for superstring compactifications on twisted tori, can be consistently relaxed. This leads to novel possibilities for constructing superstring models with fluxes and localized sources, as well as for stabilizing moduli. This also explains the ten-dimensional origin of a family of N=4 gauged supergravities, whose interpretation in type-IIA orientifold compactifications was lacking.

A KK-monopole giant graviton inAdS5×Y5

We construct a new giant graviton solution in AdS5 × Y5, with Y5 a quasi-regular Sasaki-Einstein manifold, consisting on a Kaluza-Klein monopole wrapped around the Y5 and with its Taub-NUT direction in AdS5. We find that this configuration has minimal energy when put in the centre of AdS5, where it behaves as a massless particle. When we take Y5 to be S5, we provide a microscopical description in terms of multiple gravitational waves expanding into the fuzzy S5 defined as an S1 bundle over the fuzzy CP2. Finally we provide a possible field theory dual interpretation of the construction.

CHL dyons and statistical entropy function from D1-D5 system

We give a proof of the recently proposed formula for the dyon spectrum in CHL string theories by mapping it to a configuration of D1 and D5-branes and Kaluza-Klein monopole. We also give a prescription for computing the degeneracy as a systematic expansion in inverse powers of charges. The computation can be formulated as a problem of extremizing a duality invariant statistical entropy function whose value at the extremum gives the logarithm of the degeneracy. During this analysis we also determine the locations of the zeroes and poles of the Siegel modular forms whose inverse give the dyon partition function in the CHL models.