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Yosuke Imamura

Publications and source records attributed to Yosuke Imamura.

70 records · Page 4Linked to original sources
arXiv2002

Open string - BMN operator correspondence in the weak coupling regime

We reproduce the correspondence between open string states |n> and BMN operators O_n in N=2 supersymmetric gauge theory using a worldsheet computation with the relation =O_n, where and obtain a chiral operator and BMN operators, respectively, in correspondence to them. Because we take the coupling constant to be weak and the background spacetime to be flat Minkowski, not AdS, the string states |n> are circular waves around the D3-branes, instead of KK modes on S^5. We also discuss the 1/J correction to the correspondence.

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arXiv2002

Large angular momentum closed strings colliding with D-branes

We investigate colliding processes of closed strings with large angular momenta with D-branes. We give explicit CFT calculations for closed string states with an arbitrary number of bosonic excitations and no or one fermion excitation. The results reproduce the correspondence between closed string states and single trace operators in the boundary gauge theory recently suggested by Berenstein, Maldacena and Nastase.

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arXiv2002

Gauge transformations on a D-brane in Vacuum String Field Theory

We study gauge transformations of the Hata-Kawano vector state on a D25-brane in the framework of vacuum string field theory. We show that among the infinite number of components of the polarization vector, all the components except one spacetime vector degree of freedom are gauge freedom, and give string field gauge transformations reproducing gauge transformations of the constant modes of the U(1) gauge field. These gauge transformations can be used to fix the normalization of the vector field. We also discuss a difficulty in obtaining a gauge invariant action of the vector field. Our arguments rely on the factorization ansatz of gauge transformations.

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arXiv2001

A D2-brane realization of Maxwell-Chern-Simons-Higgs systems

We show that N=2 supersymmetric Maxwell-Chern-Simons-Higgs systems in three dimension can be realized as gauge theories on a D2-brane in D8-branes background with a non-zero B-field. We reproduce a potential of Coulomb branch of the Chern-Simons theory as a potential of a D2-brane in a classical D8-brane solution and show that each Coulomb vacuum is realized by a D2-brane stabilized in the bulk at a certain distance from D8-branes.

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arXiv2000

Orientifold Planes, Type I Wilson Lines and Non-BPS D-branes

There is a longstanding puzzle concerned with the existence of Op~-planes with p>=6, which are orientifold p-planes of negative charge with stuck Dp-branes. We study the consistency of configurations with various orientifold planes and propose a resolution to this puzzle. It is argued that O6~-planes are possible in massive IIA theory with odd cosmological constant, while O7~-planes and O8~-planes are not allowed. Various relations between orientifold planes and non-BPS D-branes are also addressed.

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arXiv2000

T-duality of non-commutative gauge theories

Via T-duality a theory of open strings on a D1-brane wrapped along a cycle of slanted torus is described by a U(1) gauge theory on a D2-brane in the B-field background. It is also known that there is another dual description of the D1-brane configuration by a non-commutative gauge theory on a D2-brane. Therefore, these two gauge theories on D2-branes are equivalent. Recently, the existence of a continuous set of equivalent gauge theories including these two was suggested. We give a dual D1-brane configuration for each theory in this set, and show that the relation among parameters for equivalent gauge theories can be easily reproduced by rotation of the D1-brane configuration. We also discuss a relation between this duality and Morita equivalence.

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arXiv1999

Tachyonic modes on type 0 NS5-branes

Via T-duality, a stack of unwrapped type 0 NS5-branes is transformed into a Kaluza-Klein monopole with A_n type singularity at its center. The spectrum of twisted modes at the singularity contains tachyonic modes. We show that, in certain parameter region, this tachyonic spectrum is completely reproduced as modes of the bulk tachyon field localized on a classical NS5-brane solution. In passing, we show how twisted modes at the singularity reproduce gauge fields on stacks of NS5-branes.

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arXiv1999

Branes in type 0/type II duality

We derive relations between type 0 and type II D-brane configurations under the T-duality suggested by Bergman and Gaberdiel and confirm that the massless fields on D-branes are identical to those on the dual D-brane configurations. Furthermore, we discuss dualities of type 0 and type II NS5-branes and find that the dual of an unwrapped type 0 NS5-brane is a Kaluza-Klein monopole with non-supersymmetric blow up modes.

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arXiv1999

String junctions on backgrounds with a positively charged orientifold plane

By means of the heterotic/type IIB duality, we study properties of junctions on backgrounds with a positively charged orientifold seven-plane and D-branes, which are expected to give seven dimensional Sp(r) gauge theories. We give a modified BPS condition for the junctions and show that it reproduces the adjoint representation of the Sp(r) group.

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arXiv1998

Baryon Mass and Phase Transitions in Large N Gauge Theory

We calculate the baryon mass in N=4 large $N$ gauge theory by means of AdS/CFT correspondence and show that it is a truly bound state, at least in some situations. We find that a phase transition occurs at a critical temperature. Furthermore, we find there are bound states of W-bosons in the Higgs phase, where the gauge group is broken to SU(N_1)xSU(N_2).

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arXiv1998

Supersymmetries and BPS Configurations on Anti-de Sitter Space

We study supersymmetry breaking due to the presence of branes on anti-de Sitter space and obtain conditions for brane orientations not to break too many supersymmetries. Using the conditions, we construct a brane configuration corresponding to a baryon in large N gauge theory, and it is shown that the baryon is a marginal bound state of quarks as is expected from supersymmetry.

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arXiv1998

E_8 flavour multiplets

We analyze gauge symmetry enhancements $SO(16)\to E_8$ on eight D7-branes and $SO(14)\times U(1)\to E_8$ on seven D7-branes from open strings. String configurations which we present in this paper are closely related to the ones given by Gaberdiel and Zwiebach. Our construction is based on $SO(8)\times SO(8)$ decomposition and its relation to the D8-brane case via T-duality is clearer. Then we study supersymmetric Yang-Mills theory on D3-brane near the D7-branes. This theory has flavour symmetry group which is equal to the gauge group on D7-branes. We suggest that when this symmetry is enhanced, two dyons make bound states which, together with elementary quarks, constitute an $E_8$ multiplet.

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arXiv1997

D-particle creation on an orientifold plane

We study the propagations of gravitational wave and D-particle on D6-brane and orientifold 6-plane backgrounds in the M-theory framework. In the case of orientifold plane, D-particle number is not conserved and gravitational wave can convert into D-particle. For the simplest case, we calculate its amplitude numerically.

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arXiv1997

A Comment on Fundamental Strings in M(atrix) Theory

We present a solution of M(atrix) theory describing type IIA fundamental string. Our construction is based on the central charge of the longitudinal membrane (= fundamental string), the BPS saturation condition and the relation between M(atrix) theory and supersymmetric Yang-Mills theory. The fundamental string corresponds to a photon in supersymmetric Yang-Mills theory.

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