arXiv subjects

Nicholas P. Warner

Publications and source records attributed to Nicholas P. Warner.

At least 91 records · Page 5Linked to original sources

arXiv2008

Spectral Flow, and the Spectrum of Multi-Center Solutions

We discuss "spectral flow" coordinate transformations that take asymptotically four-dimensional solutions into other asymptotically four-dimensional solutions. We find that spectral flow can relate smooth three-charge solutions with a multi-center Taub-NUT base to solutions where one or several Taub-NUT centers are replaced by two-charge supertubes, and vice versa. We further show that multi-parameter spectral flows can map such Taub-NUT centers to more singular centers that are either D2-D0 or pure D0-brane sources. Since supertubes can depend on arbitrary functions, we establish that the moduli space of smooth horizonless black hole microstate solutions is classically of infinite dimension. We also use the physics of supertubes to argue that some multi-center solutions that appear to be bound states from a four-dimensional perspective are in fact not bound states when considered from a five- or six-dimensional perspective.

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arXiv2007

Bubbles on Manifolds with a U(1) Isometry

We investigate the construction of five-dimensional, three-charge supergravity solutions that only have a rotational U(1) isometry. We show that such solutions can be obtained as warped compactifications with a singular ambi-polar hyper-Kahler base space and singular warp factors. We show that the complete solution is regular around the critical surface of the ambi-polar base. We illustrate this by presenting the explicit form of the most general supersymmetric solutions that can be obtained from an Atiyah-Hitchin base space and its ambi-polar generalizations. We make a parallel analysis using an ambi-polar generalization of the Eguchi-Hanson base space metric. We also show how the bubbling procedure applied to the ambi-polar Eguchi-Hanson metric can convert it to a global AdS_2xS^3 compactification.

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arXiv2007

Black Holes, Black Rings and their Microstates

In this review article we describe some of the recent progress towards the construction and analysis of three-charge configurations in string theory and supergravity. We begin by describing the Born-Infeld construction of three-charge supertubes with two dipole charges, and then discuss the general method of constructing three-charge solutions in five dimensions. We explain in detail the use of these methods to construct black rings, black holes, as well as smooth microstate geometries with black hole and black ring charges, but with no horizon. We present arguments that many of these microstate geometries are dual to boundary states that belong to the same sector of the D1-D5-P CFT as the typical states. We end with an extended discussion of the implications of this work for the physics of black holes in string theory.

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arXiv2006

Mergers and Typical Black Hole Microstates

We use mergers of microstates to obtain the first smooth horizonless microstate solutions corresponding to a BPS three-charge black hole with a classically large horizon area. These microstates have very long throats, that become infinite in the classical limit; nevertheless, their curvature is everywhere small. Having a classically-infinite throat makes these microstates very similar to the typical microstates of this black hole. A rough CFT analysis confirms this intuition, and indicates a possible class of dual CFT microstates. We also analyze the properties and the merging of microstates corresponding to zero-entropy BPS black holes and black rings. We find that these solutions have the same size as the horizon size of their classical counterparts, and we examine the changes of internal structure of these microstates during mergers.

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arXiv2006

The Foaming Three-Charge Black Hole

We find a very large set of smooth horizonless geometries that have the same charges and angular momenta as the five-dimensional, maximally-spinning, three-charge, BPS black hole (J^2 = Q^3). Our solutions are constructed using a four-dimensional Gibbons-Hawking base space that has a very large number of two-cycles. The entropy of our solutions is proportional to Q^(1/2). In the same class of solutions we also find microstates corresponding to zero-entropy black rings, and these are related to the microstates of the black hole by continuous deformations.

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arXiv2006

Bubbling Supertubes and Foaming Black Holes

We construct smooth BPS three-charge geometries that resolve the zero-entropy singularity of the U(1) x U(1) invariant black ring. This singularity is resolved by a geometric transition that results in geometries without any branes sources or singularities but with non-trivial topology. These geometries are both ground states of the black ring, and non-trivial microstates of the D1-D5-P system. We also find the form of the geometries that result from the geometric transition of N zero-entropy black rings, and argue that, in general, such geometries give a very large number of smooth bound-state three-charge solutions, parameterized by 6N functions. The generic microstate solution is specified by a four-dimensional hyper-Kahler geometry of a certain signature, and contains a ``foam'' of non-trivial two-spheres. We conjecture that these geometries will account for a significant part of the entropy of the D1-D5-P black hole, and that Mathur's conjecture might reduce to counting certain hyper-Kahler manifolds.

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arXiv2006

Holographic Coulomb Branch Flows with N=1 Supersymmetry

We obtain a large, new class of N=1 supersymmetric holographic flow backgrounds with U(1)^3 symmetry. These solutions correspond to flows toward the Coulomb branch of the non-trivial N=1 supersymmetric fixed point. The massless (complex) chiral fields are allowed to develop vevs that are independent of their two phase angles, and this corresponds to allowing the brane to spread with arbitrary, U(1)^2 invariant, radial distributions in each of these directions. Our solutions are "almost Calabi-Yau:" The metric is hermitian with respect to an integrable complex structure, but is not Kahler. The "modulus squared" of the holomorphic (3,0)-form is the volume form, and the complete solution is characterized by a function that must satisfy a single partial differential equation that is closely related to the Calabi-Yau condition. The deformation from a standard Calabi-Yau background is driven by a non-trivial, non-normalizable 3-form flux dual to a fermion mass that reduces the supersymmetry to N=1. This flux also induces dielectric polarization of the D3-branes into D5-branes.

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arXiv2005

Sliding Rings and Spinning Holes

We construct smooth supergravity solutions describing a BPS black ring with a BPS black hole centered at an arbitrary distance above the ring. We find that as one moves the black hole the entropy of the ring remains constant, but the angular momentum coming from the supergravity fluxes changes. Our solutions also show that in order to merge a BPS black ring with a BPS black hole one has to increase one of the angular momenta of the ring, and that the result of the merger is always a BMPV black hole. We also find a class of mergers that are thermodynamically reversible, and comment on their physics.

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arXiv2005

Black Rings with Varying Charge Density

We find the general five-dimensional, supersymmetric black ring solutions in M-theory based upon a circular ring, but with arbitrary, fluctuating charge distributions around the ring. The solutions have three arbitrary charge distribution functions, but their asymptotic charges and angular momenta only depend upon the total charges on the ring. The arbitrary density fluctuations thus represent "hair." By varying the charge distributions one can continuously change the entropy of these black rings; to our knowledge this is the first solution in which the entropy depends on classical moduli. We also show that there is a family of solutions, with two arbitrary functions, for which the horizon remains rotationally invariant, and yet the complete solution breaks rotational symmetry. If the horizon area is set to zero then one obtains families of supertube solutions. We find that our general solutions are governed by three harmonic functions that may be thought of as classical excitations of a string. The horizon area provides a natural Lorentz metric on these excitations, and the constancy of the rotational invariance of the horizon imposes a set of Virasoro constraints.

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arXiv2005

Black Rings in Taub-NUT

We construct the most generic three-charge, three-dipole-charge, BPS black-ring solutions in a Taub-NUT background. These solutions depend on seven charges and six moduli, and interpolate between a four-dimensional black hole and a five-dimensional black ring. They are also instrumental in determining the correct microscopic description of the five-dimensional BPS black rings.

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arXiv2005

Inherited Duality and Quiver Gauge Theory

We study the duality group of $\hat{A}_{n-1}$ quiver gauge theories, primarily using their M5-brane construction. For $\mathcal{N}=2$ supersymmetry, this duality group was first noted by Witten to be the mapping class group of a torus with $n$ punctures. We find that it is a certain quotient of this group that acts faithfully on gauge couplings. This quotient group contains the affine Weyl group of $\hat{A}_{n-1}$, $\mathbb{Z}_n$ and $SL(2,\mathbb{Z})$. In fact there are $n$ non-commuting $SL(2,\mathbb{Z})$ subgroups, related to each other by conjugation using the $\mathbb{Z}_n$. When supersymmetry is broken to $\mathcal{N}=1$ by masses for the adjoint chiral superfields, an RG flow ensues which is believed to terminate at a CFT in the infrared. We find the explicit action of this duality group for small values of the adjoint masses, paying special attention to when the sum of the masses is non-zero. In the $\mathcal{N}=1$ CFT, Seiberg duality acts non-trivially on both gauge couplings and superpotential couplings and we interpret this duality as inherited from the $\mathcal{N}=2$ parent theory. We conjecture the action of S-duality in the CFT based on our results for small mass deformations. We also consider non-conformal deformations of these $\mathcal{N}=1$ theories. The cascading RG flows that ensue are a one-parameter generalization of those found by Klebanov and Strassler and by Cachazo {\it et. al.}. The universality exhibited by these flows is shown to be a simple consequence of paths generated by the action of the affine Weyl group.

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arXiv2004

One Ring to Rule Them All ... and in the Darkness Bind Them?

We construct all eleven-dimensional, three-charge BPS solutions that preserve a fixed, standard set of supersymmetries. Our solutions include all BPS three-charge rotating black holes, black rings, supertubes, as well as arbitrary superpositions of these objects. We find very large families of black rings and supertubes with profiles that follow arbitrary closed curves in the spatial R^4 transverse to the branes. The black rings copiously violate black hole uniqueness. The supertube solutions are completely regular, and generically have small curvature. They also have the same asymptotics as the three-charge black hole; and so they might be mapped to microstates of the D1-D5-p system and used to explain the entropy of this black hole.

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arXiv2004

A harmonic family of dielectric flow solutions with maximal supersymmetry

We construct a new harmonic family: dielectric flow solutions with maximal supersymmetry in eleven-dimensional supergravity. These solutions are asymptotically AdS_4 x S^7, while in the infra-red the M2 branes are dielectrically polarized into M5 branes. These solutions are holographically dual to vacua of the mass deformed theory on M2 branes. They also provide an interesting insight on the supergravity solutions sourced by giant gravitons, allowing one to see how supergravity solves the giant graviton puzzle.

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arXiv2004

The complex geometry of holographic flows of quiver gauge theories

We argue that the complete Klebanov-Witten flow solution must be described by a Calabi-Yau metric on the conifold, interpolating between the orbifold at infinity and the cone over T^(1,1) in the interior. We show that the complete flow solution is characterized completely by a single, simple, quasi-linear, second order PDE, or "master equation," in two variables. We show that the Pilch-Warner flow solution is almost Calabi-Yau: It has a complex structure, a hermitian metric, and a holomorphic (3,0)-form that is a square root of the volume form. It is, however, not Kahler. We discuss the relationship between the master equation derived here for Calabi-Yau geometries and such equations encountered elsewhere and that govern supersymmetric backgrounds with multiple, independent fluxes.

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arXiv2004

N=1 supersymmetric solutions of IIB supergravity

We present a new class of "dielectric" N=1 supersymmetric solutions of IIB supergravity. This class contains not just the ten-dimensional lift of the Leigh-Strassler renormalization group flow, but also the Coulomb branch deformation of this flow in which the branes are allowed to spread in a radially symmetric manner, preserving the SU(2) global symmetry. We use the "algebraic Killing spinor" technique, illustrating how it can be adapted to N=1 supersymmetric flows.

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arXiv2004

A Family of M-theory Flows with Four Supersymmetries

We use the techniques of "algebraic Killing spinors" to obtain a family of holographic flow solutions with four supersymmetries in M-theory. The family of supersymmetric backgrounds constructed here includes the non-trivial flow to the (2+1)-dimensional analog of the Leigh-Strassler fixed point as well as generalizations that involve the M2-branes spreading in a radially symmetric fashion on the Coulomb branch of this non-trivial fixed point theory. In spreading out, these M2-branes also appear to undergo dielectric polarization into M5-branes. Our results naturally extend the earlier applications of the "algebraic Killing spinor" method and also generalize the harmonic Ansatz in that our entire family of new supersymmetric backgrounds is characterized by the solutions of a single, second-order, non-linear PDE. We also show that our solution is a natural hybrid of special holonomy and the "dielectric deformation" of the canonical supersymmetry projector on the M2-branes.

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arXiv2004

Supersymmetric Solutions with Fluxes from Algebraic Killing Spinors

We give a general framework for constructing supersymmetric solutions in the presence of non-trivial fluxes of tensor gauge fields. This technique involves making a general Ansatz for the metric and then defining the Killing spinors in terms of very simple projectors on the spinor fields. These projectors and, through them, the spinors, are determined algebraically in terms of the metric Ansatz. The Killing spinor equations then fix the tensor gauge fields algebraically, and, with the Bianchi identities, provide a system of equations for all the metric functions. We illustrate this by constructing an infinite family of massive flows that preserve eight supersymmetries in M-theory. This family constitutes all the radially symmetric Coulomb branch flows of the softly broken, large N scalar-fermion theory on M2-branes. We reduce the problem to the solution of a single, non-linear partial differential equation in two variables. This equation governs the flow of the fermion mass, and the function that solves it then generates the entire M-theory solution algebraically in terms of the function and its first derivatives. While the governing equation is non-linear, it has a very simple perturbation theory from which one can see how the Coulomb branch is encoded.

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arXiv2003

Penrose Limits of RG Fixed Points and PP-Waves with Background Fluxes

We consider a family of pp-wave solutions of IIB supergravity. This family has a non-trivial, constant 5-form flux, and non-trivial, (light-cone) time-dependent RR and NS-NS 3-form fluxes. The solutions have either 16 or 20 supersymmetries depending upon the time dependence. One member of this family of solutions is the Penrose limit of the solution obtained by Pilch and Warner as the dual of a Leigh-Strassler fixed point. The family of solutions also provides indirect evidence in support of a recent conjecture concerning a large N duality group that acts on RG flows of N=2 supersymmetric, quiver gauge theories.

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