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Hiroshi Itoyama

Publications and source records attributed to Hiroshi Itoyama.

At least 37 records · Page 2Linked to original sources
arXiv2010

The Quiver Matrix Model and 2d-4d Conformal Connection

We review the quiver matrix model (the ITEP model) in the light of the recent progress on 2d-4d connection of conformal field theories, in particular, on the relation between Toda field theories and a class of quiver superconformal gauge theories. On the basis of the CFT representation of the beta deformation of the model, a quantum spectral curve is introduced as << det (x- i g_s \partial ϕ(z)) >>=0 at finite N and for beta \neq 1. The planar loop equation in the large N limit follows with the aid of W_n constraints. Residue analysis is provided both for the curve of the matrix model with the "multi-log" potential and for the Seiberg-Witten curve in the case of SU(n) with 2n flavors, leading to the matching of the mass parameters. The isomorphism of the two curves is made manifest.

hep-th↗
arXiv2010

Method of Generating q-Expansion Coefficients for Conformal Block and N=2 Nekrasov Function by beta-Deformed Matrix Model

We observe that, at beta-deformed matrix models for the four-point conformal block, the point q=0 is the point where the three-Penner type model becomes a pair of decoupled two-Penner type models and where, in the planar limit, (an array of) two-cut eigenvalue distribution(s) coalesce into (that of) one-cut one(s). We treat the Dotsenko-Fateev multiple integral, with their paths under the recent discussion, as perturbed double-Selberg matrix model (at q=0, it becomes a pair of Selberg integrals) to construct two kinds of generating functions for the q-expansion coefficients and compute some. A formula associated with the Jack polynomial is noted. The second Nekrasov coefficient for SU(2) with N_f =4 is derived. A pair of Young diagrams appears naturally. The finite N loop equation at q=0 as well as its planar limit is solved exactly, providing a useful tool to evaluate the coefficients as those of the resolvents. The planar free energy in the q-expansion is computed to the lowest non-trivial order. A free field representation of the Nekrasov function is given.

hep-th↗
arXiv2009

Low Energy Processes Associated with Spontaneously Broken N=2 Supersymmetry

We consider low energy processes described by the N=2 supercurrent on its partially (to N=1) and spontaneously broken vacuum and the attendant Nambu-Goldstone fermion (NGF), which the presence of the electric and magnetic Fayet-Iliopoulos (FI) terms is responsible for. We show suppressions of amplitudes decaying into the NGF as its momentum becomes small. In the lagrangian realization (namely, the model of arXiv:hep-th/0409060) of the conserved supercurrent, the NGF resides in the overall U(1), which is nonetheless not decoupled, and interacts with the SU(N) sector through nonderivative as well as derivative couplings. The low energy suppression is instead accomplished by a cancellation between the annihilation diagram from the Yukawa couplings and the contact four-Fermi terms. We give a complete form of the supercurrent and the model is recast in more transparent notation.

hep-th↗
arXiv2009

Orientifolded Matrices and Supersymmetries that Give Rise to Spacetime Directional Asymmetry of Effective Interactions

Effects of matrix orientifolding that preserves supersymmetries are considered in the IIB matrix model with regard to its effective dynamics generated for diagonal elements. Taking the case of maximal supersymmetries and the long distance expansion of the one-loop effective action as well as cases where the size of the matrices is small, we demonstrate that the directional asymmetry of spacetime brought upon by this setup in fact leads to that of the forces exerting on the spacetime points: in addition to the two-body attraction between two points, there are attractions toward the four dimensional plate.

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arXiv2008

Deformation of Dijkgraaf-Vafa Relation via Spontaneously Broken N=2 Supersymmetry II

We consider the matter induced part of the effective superpotential of N=2, U(N) gauge model in which N=2 supersymmetry is spontaneously broken to N=1, by using the properties of the chiral ring and the generalized Konishi anomaly equations derived in our previous paper arXiv:0704.1060. It is shown that the effective superpotential is related to the planar free energy of the matrix model by a formula which consists of two parts -- the well-known part due to Dijkgraaf-Vafa and the part that acts as a deformation of the couplings. These couplings are those of the original bare prepotential in the action and at the same time matrix model couplings.

hep-th↗
arXiv2008

Nambu-Goto Like Action for the AdS_5 x S^5 Superstrings in the Generalized Light-Cone Gauge

We reinvestigate the kappa-symmetry-fixed Green-Schwarz action in the AdS_5 x S^5 background in a version of the light-cone gauge. In the generalized light-cone gauge, the action has been written in the phase space variables. We convert it into the standard action written in terms of the fields and their derivatives. We obtain a Nambu-Goto type action which has the correct flat-space limit.

hep-th↗
arXiv2007

Deformation of Dijkgraaf-Vafa Relation via Spontaneously Broken N=2 Supersymmetry

It is known that the fermionic shift symmetry of the N=1, U(N) gauge model with a superpotential of an adjoint chiral superfield is replaced by the second (spontaneously broken) supersymmetry in the N=2, U(N) gauge model with a prepotential and Fayet-Iliopoulos parameters. Based on a diagrammatic analysis, we demonstrate how the well-known form of the effective superpotential in the former model is modified in the latter. A set of two equations on the one-point functions stating the Konishi anomaly is modified accordingly.

hep-th↗
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.

hep-th↗
arXiv2007

U(N) Gauged N=2 Supergravity and Partial Breaking of Local N=2 Supersymmetry

We study a minimal model of U(N) gauged N=2 supergravity with one hypermultiplet parametrizing SO(4,1)/SO(4) quaternionic manifold. Local N=2 supersymmetry is known to be spontaneously broken to N=1 in the Higgs phase of U(1)_{graviphoton} \times U(1). Several properties are obtained of this model in the vacuum of unbroken SU(N) gauge group. In particular, we derive mass spectrum analogous to the rigid counterpart and put the entire effective potential on this vacuum in the standard superpotential form of N=1 supergravity.

hep-th↗
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.

hep-th↗
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.

hep-th↗
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.

hep-th↗
arXiv2005

Matrix Orientifolding and Models with Four or Eight Supercharges

The conditions under which matrix orientifolding and supersymmetry transformations commute are known to be stringent. Here we present the cases possessing four or eight supercharges upon ${\bf Z}_3$ orbifolding followed by matrix orientifolding. These cases descend from the matrix models with eight plus eight supercharges. There are fifty in total, which we enumerate.

hep-th↗
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.

hep-th↗
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.

hep-th↗
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.

hep-th↗
arXiv2002

Off-shell Crosscap State and Orientifold Planes with Background Dilatons

We show that a non-trivial dilaton condensation alters the dimensions of orientifold planes. An off-shell crosscap state which naturally interpolates between the usual on-shell crosscap states and their T-duals plays an important role in the analysis. We present an explicit representation of the off-shell crosscap state on an RP2 worldsheet in the gauge in which the worldsheet curvature in the bulk of the fundamental region of the RP2 vanishes. We show that the non-trivial dilaton condensation reproduces the correct descent relation among orientifold plane tensions.

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