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Minoru Eto

Publications and source records attributed to Minoru Eto.

135 records · Page 8Linked to original sources

Global Structure of Moduli Space for BPS Walls

We study the global structure of the moduli space of BPS walls in the Higgs branch of supersymmetric theories with eight supercharges. We examine the structure in the neighborhood of a special Lagrangian submanifold M, and find that the dimension of the moduli space can be larger than that naively suggested by the index theorem, contrary to previous examples of BPS solitons. We investigate BPS wall solutions in an explicit example of M using Abelian gauge theory. Its Higgs branch turns out to contain several special Lagrangian submanifolds including M. We show that the total moduli space of BPS walls is the union of these submanifolds. We also find interesting dynamics between BPS walls as a byproduct of the analysis. Namely, mutual repulsion and attraction between BPS walls sometimes forbid a movement of a wall and lock it in a certain position; we also find that a pair of walls can transmute to another pair of walls with different tension after they pass through.

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Effective Theory on Non-Abelian Vortices in Six Dimensions

Non-Abelian vortices in six spacetime dimensions are obtained for a supersymmetric U(N) gauge theory with N hypermultiplets in the fundamental representation. Massless (moduli) fields are identified and classified into Nambu-Goldstone and quasi-Nambu-Goldstone fields. Effective gauge theories for the moduli fields are constructed on the four-dimensional world volume of vortices. A systematic method to obtain the most general form of the effective Lagrangian consistent with symmetry is proposed. The moduli space for the multi-vortices is found to be a vector bundle over the complex Grassmann manifold.

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Non-BPS walls and their stability in 5d SUSY theory

We review recent work (hep-th/0404114) on non-BPS domain walls in $5d$ SUSY theory. An exact solution of non-BPS multi-walls is found in supersymmetric massive T*(CP1) model in five dimensions. The non-BPS multi-wall solution is found to have no tachyon. The N=1 supersymmetry preserved on the four-dimensional world volume of one wall is broken by the coexistence of the other wall. The supersymmetry breaking is exponentially suppressed as the distance between the walls increases.

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Radius Stabilization in a Supersymmetric Warped Compactification

A supersymmetric (SUSY) model of radius stabilization is constructed for the S^1/Z_2 warped compactifications with a hypermultiplet in five dimensions. Requiring the continuity of scalar field across the boundaries, we obtain radius stabilization preserving SUSY, realizing the SUSY extension of the Goldberger-Wise mechanism. Even if we allow discontinuities of the Z_2 odd field across the boundary, we always obtain SUSY preservation but obtain the radius stabilization only when the discontinuity is fixed by other mechanism.

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Non-BPS Walls and Their Stability in 5D Supersymmetric Theory

An exact solution of non-BPS multi-walls is found in supersymmetric massive T^\star(\mathbb{CP}^1) model in five dimensions. The non-BPS multi-wall solution is found to have no tachyon. Although it is only metastable under large fluctuations, we can give topological stability by considering a model with a double covering of the T^\star(\mathbb{CP}^1) target manifold. The {\cal N}=1 supersymmetry preserved on the four-dimensional world volume of one wall is broken by the coexistence of the other wall. The supersymmetry breaking is exponentially suppressed as the distance between the walls increases.

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BPS Multi-Walls in Five-Dimensional Supergravity

Exact BPS solutions of multi-walls are obtained in five-dimensional supergravity. The solutions contain 2n parameters similarly to the moduli space of the corresponding global SUSY models and have a smooth limit of vanishing gravitational coupling. The models are constructed as gravitational deformations of massive T^*CP^n nonlinear sigma models by using the off-shell formulation of supergravity and massive quaternionic quotient method with U(1)*U(1) gauging. We show that the warp factor can have at most single stationary point in this case. We also obtain BPS multi-wall solutions even for models which reduce to generalizations of massive T^*CP^n models with only U(1)^n isometry in the limit of vanishing gravitational coupling. At particular values of parameters, isometry of the quaternionic manifolds is enhanced.

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Solvable Models of Domain Walls in N=1 Supergravity

A class of exactly solvable models of domain walls are worked out in D=4 ${\cal N}=1$ supergravity. We develop a method to embed globally supersymmetric theories with exact BPS domain wall solutions into supergravity, by introducing a gravitationally deformed superpotential. The gravitational deformation is natural in the spirit of maintaining the Kähler invariance. The solutions of the warp factor and the Killing spinor are also obtained. We find that three distinct behaviors of warp factors arise depending on the value of a constant term in the superpotential : exponentially decreasing in both sides of the wall, flat in one side and decreasing in the other, and increasing in one side and decreasing in the other. Only the first possibility gives the localized massless graviton zero mode. Models with multi-walls and models with runaway vacua are also discussed.

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Stability and Fluctuations on Walls in N=1 Supergravity

The recently found non-BPS multi-wall configurations in the N=1 supergravity in four dimensions is shown to have no tachyonic scalar fluctuations without additional stabilization mechanisms. Mass of radion (lightest massive fluctuation) is found to be proportional to $Lambda {\rm e}^{-πΛR/2}$, where $Λ$ is the inverse width of the wall and $ R$ is the radius of compactified dimension. We obtain localized massless graviton and gravitino forming a supermultiplet with respect to the Killing spinor. The relation between the bulk energy density and the boundary energy density (cosmological constants) is an automatic consequence of the field equation and Einstein equation. In the limit of vanishing gravitational coupling, the Nambu-Goldstone modes are reproduced.

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Exactly solved BPS wall and winding number in N=1 Supergravity

A BPS exact wall solution is found in N=1 supergravity in four dimensions. The model uses chiral scalar field with a periodic superpotential admitting winding numbers. Maintaining the periodicity in supergravity requires a gravitational correction to superpotential which allows the exact solution. By introducing boundary cosmological constants, we construct non-BPS multi-wall solutions for which a systematic analytic approximation is worked out for small gravitational coupling.

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