arXiv subjects

Hitoshi Nishino

Publications and source records attributed to Hitoshi Nishino.

At least 55 records · Page 3Linked to original sources

arXiv2003

Supermembrane with Non-Abelilan Gauging and Chern-Simons Quantization

We present non-Abelian gaugings of supermembrane for general isometries for compactifications from eleven-dimensions, starting with Abelian case as a guide. We introduce a super Killing vector in eleven-dimensional superspace for a non-Abelian group G associated with the compact space B for a general compactification, and couple it to a non-Abelian gauge field on the world-volume. As a technical tool, we use teleparallel superspace with no manifest local Lorentz covariance. Interestingly, the coupling constant is quantized for the non-Abelian group G, due to its generally non-trivial mapping π_3(G).

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arXiv2003

Noncommutative Self-Dual Supersymmetric Yang-Mills Theory

We formulate noncommutative self-dual N=4 supersymmetric Yang-Mills theory in D=2+2 dimensions. As in the corresponding commutative case, this theory can serve as the possible master theory of all the noncommutative supersymmetric integrable models in lower dimensions. As a by-product, noncommutative self-dual N=2 supersymmetric Yang-Mills theory is obtained in D=2+2. We also perform a dimensional reduction of the N=2 theory further into N=(2,2) in D=1+1, as a basis for more general future applications. As a typical example, we show how noncommutative integrable matrix N=(1,0) supersymmetric KdV equations in D=1+1 arise from this theory, via the Yang-Mills gauge groups GL(n, R) or SL(2n, R).

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arXiv2003

Self-Dual Supergravity in Seven Dimensions with Reduced Holonomy G_2

We present self-dual N=2 supergravity in superspace for Euclidean seven dimensions with the reduced holonomy G_2 \subset SO(7), including all higher-order terms. As its foundation, we first establish N=2 supergravity without self-duality in Euclidean seven dimensions. We next show how the generalized self-duality in terms of octonion structure constants can be consistently imposed on the superspace constraints. We found two self-dual N=2 supergravity theories possible in 7D, depending on the representations of the two spinor charges of N=2. The first formulation has both of the two spinor charges in the {\bf 7} of G_2 with 24 + 24 on-shell degrees of freedom. The second formulation has both charges in the {\bf 1} of G_2 with 16 + 16 on-shell degrees of freedom.

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arXiv2003

Self-Dual N=(1,0) Supergravity in Eight Dimensions with Reduced Holonomy Spin(7)

We construct chiral N=(1,0) self-dual supergravity in Euclidean eight-dimensions with reduced holonomy Spin(7), including all the higher-order interactions in a closed form. We first establish the non-chiral N=(1,1) superspace supergravity in eight-dimensions with SO(8) holonomy without self-duality, as the foundation of the formulation. In order to make the whole computation simple, and the generalized self-duality compatible with supersymmetry, we adopt a particular set of superspace constraints similar to the one originally developed in ten-dimensional superspace. The intrinsic properties of octonionic structure constants make local supersymmetry, generalized self-duality condition, and reduced holonomy Spin(7) all consistent with each other.

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arXiv2003

Noncommutative Nonlinear Supersymmetry

We present noncommutative nonlinear supersymmetric theories. The first example is a non-polynomial Akulov-Volkov-type lagrangian with noncommutative nonlinear global supersymmetry in arbitrary space-time dimensions. The second example is the generalization of this lagrangian to Dirac-Born-Infeld lagrangian with nonlinear supersymmetry realized in dimensions D=2,3,4, 6 and 10.

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arXiv2002

Gauged N=2 Supergravity in Nine-Dimensions and Domain Wall Solutions

We present massive N=2 supergravity with SO(2)-gauging in nine-dimensions by direct construction. A full lagrangian and transformation rules are fixed, respectively up to quartic and quadratic fermion terms. Corresponding to the generalized Scherk-Schwarz dimensional reduction utilizing SL(2,R) symmetry, this theory allows three arbitrary mass parameters m_0, m_1and m_2 in addition to the minimal gauge coupling g, so that our system has the most general form compared with other results in the past. Unlike ordinary gauged maximal supergravity theories in other dimensions, the scalar potential is positive definite for arbitrary values of the mass parameters. As an application, we also analyze the stability and supersymmetry for 7-brane domain wall solutions for this gauged maximal supergravity, keeping the three mass parameters.

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arXiv2002

Topologican Gauging of N=16 Supergravity in Three-Dimensions

We present a topologically non-trivial generalization of gauged N=16 supergravity on the coset E_8 / SO(16) in three-dimensions. This formulation is based on a combination of BF-term and a Chern-Simons term for an SO(16) gauge field A_\m{}^{I J}. The fact that an additional vector field B_\m{}^{I J} is physical and propagating with couplings to σ-model fields makes our new gauging non-trivial and different from the conventional one. Even though the field strength of the A_\m{}^{I J}-field vanishes on-shell, the action is topologically non-trivial due to non-vanishing π_3-homotopy. We also present an additional modifications by an extra Chern-Simons term. As by-products, we give also an application to N=9 supergravity coupled to a σ-model on the coset F_4 / SO(9), and a new BF-Chern-Simons theory coupled to ^\forall N extended supergravity.

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arXiv2002

Generalized BF Theory in Superspace as Underlying Theory of 11D Supergravity

We construct a generalized BF theory in superspace that can embed eleven-dimensional supergravity theory. Our topological BF theory can accommodate all the necessary Bianchi identities for teleparallel superspace supergravity in eleven-dimensions, as the simplest but nontrivial solutions to superfield equations for our superspace action. This indicates that our theory may have solutions other than eleven-dimensional supergravity, accommodating generalized theories of eleven-dimensional supergravity. Therefore our topological theory can be a good candidate for the low energy limit of M-theory, as an underlying fundamental theory providing a `missing link' between eleven-dimensional supergravity and M-theory.

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arXiv2002

Axisymmetric Gravitational Solutions as Possible Classical Backgrounds around Closed String Mass Distributions

By studying singularities in stationary axisymmetric Kerr and Tomimatsu-Sato solutions with distortion parameter \d = 2, 3, ... in general relativity, we conclude that these singularities can be regarded as nothing other than closed string-like circular mass distributions. We use two different regularizations to identify \d-function type singularities in the energy-momentum tensor for these solutions, realizing a regulator independent result. This result gives supporting evidence that these axisymmetric exact solutions may well be the classical solutions around closed string-like mass distributions, just like Schwarzschild solution corresponding to a point mass distribution. In other words, these axisymmetric exact solutions may well provide the classical backgrounds around closed strings.

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arXiv2002

Supersymmetric E_{8(+8)} / SO(16) Sigma-Model Coupled to N=1 Supergravity in Three-Dimensions

A three-dimensional simple N=1 supergravity theory with a supersymmetric sigma-model on the coset E_{8(+8)} / SO(16) is constructed. Both bosons and fermions in the matter multiplets are in the spinorial 128-representation of SO(16) with the same chirality. Due to their common chirality, this model can not be obtained from the maximal N=16 supergravity. By introducing an independent vector multiplet, we can also gauge an arbitrary subgroup of SO(16) together with a Chern-Simons term. Similar N=1 supersymmetric sigma-models coupled to supergravity are also constructed for the cosets F_{4(-20)} / SO(9) and SO(8,n) / SO(8) X SO(n).

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arXiv2002

Teleparallel Complex Gravity as Foundation for Noncommutative Gravity

We present a teleparallel complex gravity as the foundation for the formulation of noncommutative gravity theory. The negative energy ghosts in the conventional formulation with U(1,3) local Lorentz connection no longer exists, since the local Lorentz invariance is broken down to U(1,3) global Lorentz symmetry. As desired, our teleparallel complex gravity theory also passes the key classical test of perihelion advance of Mercury. Based on this result, we present a lagrangian for the noncommutative teleparallel gravity theory.

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arXiv2001

Unimodular Supergravity

We present the locally supersymmetric formulation of unimodular gravity theory in D (1\le D \le 11) dimensions, namely supergravity theory with the metric tensor whose determinant is constrained to be unity. In such a formulation, the usual fine-tuning of cosmological constant is no longer needed, but its value is understood as an initial condition. Moreover, the zero-ness of the cosmological constant is concluded as the most probable configuration, based on the effective vacuum functional. We also show that the closure of supersymmetry gauge algebra is consistent with the unimodular condition on the metric.

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arXiv2001

Noncommutative Supersymmetric Yang-Mills Theory in Ten-Dimensions with Higher-Derivative Terms

We present an action for noncommutative supersymmetric Yang-Mills theory in ten-dimensions, and confirm its invariance under supersymmetry. We next add higher-order derivative terms to such a noncommutative supersymmetric action. These terms contain fields as high as the quartic order. This resulting action can be regarded as supersymmetric generalization of noncommutative non-Abelian Dirac-Born-Infeld action. Some ambiguities related to field redefinitions are also clarified.

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arXiv2001

Teleparallel Superspace in Eleven Dimensions Coupled to Supermembranes

We present a superspace formulation of N=1 eleven-dimensional supergravity with no manifest local Lorentz covariance, which we call teleparallel superspace. This formulation will be of great importance, when we deal with other supergravity theories in dimensions higher than eleven dimensions, or a possible formulation of noncommutative supergravity. As an illustrative example, we apply our teleparallel superspace formulation to the case of N=1 supergravity in twelve-dimensions. We also show the advantage of teleparallel superspace as backgrounds for supermembrane action.

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arXiv2001

A Note on Embedding of M-Theory Corrections into Eleven-Dimensional Superspace

By analyzing eleven-dimensional superspace fourth-rank superfield strength F-Bianchi identities, we show that M-theory corrections to eleven-dimensional supergravity can not be embedded into the mass dimension zero constraints, such as the (\g^{a b})_{\a\b} X_{a b}{}^c or i (\g^{a_1... a_5})_{\a\b} X_{a_1... a_5}{}^c -terms in the supertorsion constraint T_{\a\b}{}^c. The only possible modification of superspace constraint at dimension zero is found to be the scaling of F_{\a\b c d} like F_{\a\b c d} = (1/2) \big(\g_{c d}\big)_{\a\b} e^Φfor some real scalar superfield Φ, which alone is further shown not enough to embed general M-theory corrections. This conclusion is based on the dimension zero F-Bianchi identity under the two assumptions: (i) There are no negative dimensional constraints on the F-superfield strength: F_{\a\b\g\d} = F_{\a\b\g d} =0; (ii) The supertorsion T-Bianchi identities and F-Bianchi identities are not modified by Chern-Simons terms. Our result can serve as a powerful tool for future exploration of M-theory corrections embedded into eleven-dimensional superspace supergravity.

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arXiv2001

Alternative N=2 Supergravity in Singular Five Dimensions with Matter/Gauge Couplings

We present an extended study of our previous work on an alternative five-dimensional N=2 supergravity theory that has a single antisymmetric tensor and a dilaton as a part of supergravity multiplet. The new fields are natural Neveu-Schwarz massless fields in superstring theory. Our total matter multiplets include n copies of vector multiplets forming the sigma-model coset space SO(n,1) / SO(n), and n' copies of hypermultiplets forming the quaternionic Kähler manifold Sp(n',1) / Sp(n') X Sp(1). We complete the couplings of matter multiplets to supergravity with the gauged group of the type SO(2) X Sp(n') X Sp(1) X H X [ U(1) ]^{n-p+1} for an arbitrary gauge group H with p = dim H + 1, and the isotropy group Sp(n') X Sp(1) of the coset Sp(n',1) / Sp(n') X Sp(1) formed by the hypermultiplets. We also describe the generalization to singular 5D space-time as in the conventional formulation

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arXiv2001

Deliberations on 11D Superspace for the M-Theory Effective Action

In relation to the superspace modifications of 11D supergeometry required to describe the M-theory low-energy effective action, we present an analysis of infinitesimal supergravity fluctuations about the flat superspace limit. Our investigation confirms Howe's interpretation of our previous Bianchi identity analysis. However, the analysis also shows that should 11D supergravity obey the rules of other off-shell supergravity theories, the complete M-theory corrections will necessarily excite our previously anticipated spin-1/2 engineering dimension-1/2 spinor auxiliary multiplet superfield. The analysis of fluctuations yields more evidence that Howe's 1997 theorem is specious when applied to Poincar\' e supergravity or 11D supergravity/M-theory. We end by commenting upon recent advances in this area.

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arXiv2001

Alternative N=2 Supergravity in Five Dimensions with Singularities

We present an alternative N=2 supergravity multiplet coupled to n copies of vector multiplets and n' copies of hypermultiplets in five dimensions. Our supergravity multiplet contains a single antisymmetric tensor and a dilaton, which are natural Neveu-Schwarz massless fields in superstring theory. The absence of the explicit Chern-Simons terms in our lagrangian deletes the non-trivial constraints on the couplings of vector multiplets in the conventional formulation. The scalars in the vector multiplets form the sigma-model for the coset SO(n,1) / SO(n), like those in the vector multiplets coupled to N=1 supergravity in nine dimensions, while the scalars in the hypermultiplets form that for the quaternionic Kahler manifold Sp(n',1) / Sp(n') X Sp(1). We also perform the gauging of the SO(2) subgroup of the Sp(1) = SL(2,R) automorphism group of N=2 supersymmetry. Our result is also generalized to singular 5D space-time as in the conventional formulation, as a preliminary for supersymmetric Randall-Sundrum brane world scenario.

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