arXiv subjects

Makoto Sakaguchi

Publications and source records attributed to Makoto Sakaguchi.

At least 37 records · Page 2Linked to original sources

arXiv2007

N=2 Quiver Gauge Model and Partial Supersymmetry Breaking

We construct an action of N=2 affine $A_n$ quiver gauge model having non-canonical kinetic terms and equipped with electric and magnetic FI terms. N=2 supersymmetry is shown to be broken to N=1 spontaneously and N=1 multiplets realized on the vacua are given. We also mention the models with different gauge groups. It is argued that the affine $A_1$ quiver gauge model provides a dynamical realization to approach the Klebanov-Witten N=1 fixed point.

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arXiv2007

Non-relativistic String and D-branes on AdS_5 x S^5 from Semiclassical Approximation

We show that non-relativistic actions of string and D-branes on AdS_5 x S^5 can be reproduced as a semiclassical approximation of the string and D-brane actions around static 1/2 BPS configurations. This is contrastive to the Penrose limit. For example, the pp-wave string can be recaptured as a semiclassical approximation around a 1/2 BPS particle rotating at the velocity of light. We argue that small deformation of a straight Wilson line would give a composite operator in the gauge-theory side that corresponds to a semiclassical state of the non-relativistic string, according to the semiclassical interpretation.

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arXiv2007

A Covariant Approach to Noncommutative M5-branes

We briefly review how to discuss noncommutative (NC) M5-branes and intersecting NC M5-branes from kappa-invariance of an open supermembrane action with constant three-form fluxes. The kappa-invariance gives rise to possible Dirichlet brane configurations. We shortly summarize a construction of projection operators for NC M5-branes and some intersecting configurations of NC M5-branes. A strong flux limit of them is also discussed.

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arXiv2007

Intersecting Noncommutative M5-branes from Covariant Open Supermembrane

We study intersecting noncommutative (NC) M5-branes from κ-invariance of an open supermembrane action with constant three-form fluxes. The $κ$-invariance gives rise to possible D-brane configurations for which projection operators can be determined. We construct projection operators for two types of 1/4 BPS intersecting NC M5-branes. The one is an intersection of two NC M5-branes: NC M5\bot NC M5 (3). The other is that of a NC M5-brane and a commutative (C) M5-brane: NC M5\bot C M5 (1). A NC M5-brane can be viewed as a bound state of M5 and M2, and the configurations M2\bot M5 (1) and M2\bot M2 (0) are realized on the intersecting M5-branes. Taking a commutative limit the allowed intersecting M5-branes are surely reproduced: M5\bot M5 (3) and M5\bot M5 (1).

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arXiv2006

Spontaneous Partial Breaking of N=2 Supersymmetry and the U(N) Gauge Model

We briefly review the properties of the N=2 U(N) gauge model with/without matters. On the vacua, N=2 supersymmetry and the gauge symmetry are spontaneously broken to N=1 and a product gauge group, respectively. The masses of the supermultiplets appearing on the N=1 vacua are given. We also discuss the relation to the matrix model.

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arXiv2006

Noncommutative M-branes from Covariant Open Supermembranes

We discuss an open supermembrane in the presence of a constant three-form. The boundary conditions to ensure the kappa-invariance of the action lead to possible Dirichlet branes. It is shown that a noncommutative (NC) M5-brane is possible as a boundary and the self-duality condition that the flux on the world-volume satisfies is derived from the requirement of the kappa-symmetry. We also find that the open supermembrane can attach to each of infinitely many M2-branes on an M5-brane, namely a strong flux limit of the NC M5-brane.

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arXiv2006

Partial Supersymmetry Breaking and N=2 U(N_c) Gauge Model with Hypermultiplets in Harmonic Superspace

We provide a manifestly N=2 supersymmetric formulation of the N=2 U(N_c) gauge model constructed in terms of N=1 superfields in hep-th/0409060. The model is composed of N=2 vector multiplets in harmonic superspace and can be viewed as the N=2 U(N_c) Yang-Mills effective action equipped with the electric and magnetic Fayet-Iliopoulos terms. We generalize this gauge model to an N=2 U(N_c) QCD model by introducing N=2 hypermultiplets in harmonic superspace which include both the fundamental representation of U(N_c) and the adjoint representation of U(N_c). The effect of the magnetic Fayet-Iliopoulos term is to shift the auxiliary field by an imaginary constant. Examining vacua of the model, we show that N=2 supersymmetry is spontaneously broken down to N=1.

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arXiv2006

Non-Relativistic AdS Branes and Newton-Hooke Superalgebra

We examine a non-relativistic limit of D-branes in AdS_5xS^5 and M-branes in AdS_{4/7}xS^{7/4}. First, Newton-Hooke superalgebras for the AdS branes are derived from AdSxS superalgebras as Inonu-Wigner contractions. It is shown that the directions along which the AdS-brane worldvolume extends are restricted by requiring that the isometry on the AdS-brane worldvolume and the Lorentz symmetry in the transverse space naturally extend to the super-isometry. We also derive Newton-Hooke superalgebras for pp-wave branes and show that the directions along which a brane worldvolume extends are restricted. Then the Wess-Zumino terms of the AdS branes are derived by using the Chevalley-Eilenberg cohomology on the super-AdSxS algebra, and the non-relativistic limit of the AdS-brane actions is considered. We show that the consistent limit is possible for the following branes: Dp (even,even) for p=1 mod 4 and Dp (odd,odd) for p=3 mod 4 in AdS_5xS^5, and M2 (0,3), M2 (2,1), M5 (1,5) and M5 (3,3) in AdS_{4}xS^{7} and S^{4}xAdS_{7}. We furthermore present non-relativistic actions for the AdS branes.

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arXiv2006

Noncommutative D-brane from Covariant AdS Superstring

We explore noncommutative D-branes in the AdS_5xS^5 background from the viewpoint of κ-invariance of a covariant open string action in the Green-Schwarz formulation. Boundary conditions to ensure the κ-invariance of the action lead to possible configurations of noncommutative D-branes. With this covariant method, we derive configurations of 1/4 BPS noncommutative D-branes. The resulting D-branes other than D-string are 1/4 BPS at any places, and the D-string is exceptional and it is 1/2 BPS at the origin and 1/4 BPS outside the origin. All of them are reduced to possible 1/4 BPS or 1/2 BPS AdS D-branes in the commutative limit or the strong magnetic flux limit. We also apply the same analysis to an open superstring in the pp-wave background and derive configurations of 1/4 BPS noncommutative D-branes in the pp-wave. These D-branes consistently related to AdS D-branes via the Penrose limit.

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arXiv2006

Supersymmetric U(N) Gauge Model and Partial Breaking of N=2 Supersymmetry

We review the construction of the N=2 U(N) gauge model and the analysis of vacua of the model. On the vacua, N=2 supersymmetry is spontaneously broken to N=1, and the gauge symmetry is broken to a product gauge group \prod_{i=1}^n U(N_i). The masses of the supermultiplets appearing on the N=1 vacua are given. We provide a manifestly N=2 supersymmetric formulation of the U(N) gauge model coupled with N=2 hypermultiplets, and show that N=2 supersymmetry is partially broken down to N=1 spontaneously.

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arXiv2005

Scalar Laplacian on Sasaki-Einstein Manifolds Y^{p,q}

We study the spectrum of the scalar Laplacian on the five-dimensional toric Sasaki-Einstein manifolds Y^{p,q}. The eigenvalue equation reduces to Heun's equation, which is a Fuchsian equation with four regular singularities. We show that the ground states, which are given by constant solutions of Heun's equation, are identified with BPS states corresponding to the chiral primary operators in the dual quiver gauge theories. The excited states correspond to non-trivial solutions of Heun's equation. It is shown that these reduce to polynomial solutions in the near BPS limit.

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arXiv2005

Partial Breaking of N=2 Supersymmetry and of Gauge Symmetry in the U(N) Gauge Model

We explore vacua of the U(N) gauge model with N=2 supersymmetry recently constructed in hep-th/0409060. In addition to the vacuum previously found with unbroken U(N) gauge symmetry in which N=2 supersymmetry is partially broken to N=1, we find cases in which the gauge symmetry is broken to a product gauge group \prod_{i=1}^n U(N_i). The N=1 vacua are selected by the requirement of a positive definite Kahler metric. We obtain the masses of the supermultiplets appearing on the N=1 vacua.

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arXiv2005

Notes on Five-dimensional Kerr Black Holes

The geometry of five-dimensional Kerr black holes is discussed based on geodesics and Weyl curvatures. Kerr-Star space, Star-Kerr space and Kruskal space are naturally introduced by using special null geodesics. We show that the geodesics of AdS Kerr black hole are integrable, which generalizes the result of Frolov and Stojkovic. We also show that five-dimensional AdS Kerr black holes are isospectrum deformations of Ricci-flat Kerr black holes in the sense that the eigenvalues of the Weyl curvature are preserved.

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arXiv2005

Supersymmetric U(N) Gauge Model and Partial Breaking of N=2 Supersymmetry

Guided by the gauging of U(N) isometry associated with the special Kahler geometry, and the discrete R symmetry, we construct the N=2 supersymmetric action of a U(N) invariant nonabelian gauge model in which rigid N=2 supersymmetry is spontaneously broken to N=1. This generalizes the abelian model considered by Antoniadis, Partouche and Taylor. We shed light on complexity of the supercurrents of our model associated with a broken N=2 supermultiplet of currents, and discuss the spontaneously broken supersymmetry as an approximate fermionic shift symmetry.

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arXiv2004

Seven-dimensional Einstein Manifolds from Tod-Hitchin Geometry

We construct infinitely many seven-dimensional Einstein metrics of weak holonomy G_2. These metrics are defined on principal SO(3) bundles over four-dimensional Bianchi IX orbifolds with the Tod-Hitchin metrics. The Tod-Hitchin metric has an orbifold singularity parameterized by an integer, and is shown to be similar near the singularity to the Taub-NUT de Sitter metric with a special charge. We show, however, that the seven-dimensional metrics on the total space are actually smooth. The geodesics on the weak G_2 manifolds are discussed. It is shown that the geodesic equation is equivalent to the Hamiltonian equation of an interacting rigid body system. We also discuss M-theory on the product space of AdS_4 and the seven-dimensional manifolds, and the dual gauge theories in three-dimensions.

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arXiv2004

U(N) Gauge Model and Partial Breaking of N=2 Supersymmetry

We briefly review a construction of N=2 supersymmetric U(N) gauge model in which rigid N=2 supersymmetry is spontaneously broken to N=1. This model generalizes the abelian model considered by Antoniadis, Patouche and Taylor. We discuss the conditions on the vacua of the model with partial supersymmetry breaking.

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arXiv2004

D-branes of Covariant AdS Superstrings -- An Overview --

We briefly review a covariant analysis of D-branes of type IIB superstring on the AdS_5xS^5 background from the κ-invariance of the Green-Schwarz string action. The possible configurations of D-branes preserving half of supersymmetries are classified in both cases of AdS_5xS^5 and the pp-wave background.

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arXiv2004

Sasaki-Einstein Twist of Kerr-AdS Black Holes

We consider Kerr-AdS black holes with equal angular momenta in arbitrary odd spacetime dimensions \ge 5. Twisting the Killing vector fields of the black holes, we reproduce the compact Sasaki-Einstein manifolds constructed by Gauntlett, Martelli, Sparks and Waldram. We also discuss an implication of the twist in string theory and M-theory.

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