We show that a special type of colliding 7-brane configuration of a
codimension-two singularity realizes not only a six-dimensional spectrum with
exactly the same quantum numbers as that of the three-generation E7/(SU(5) x
U(1)^3) coset family uni...

A supersymmetric solution to type II supergravity is constructed by
superposing two hyperkähler with torsion metrics. The solution is given by a
Käler with torsion metric with holonomy. The metric is embedded into
a heterotic solution ...

F-theory Family Unification

Shun'ya Mizoguchi

JHEP 1407(018) 1-39 May 2014 [Refereed]

We propose a new geometric mechanism for naturally realizing unparallel three families of flavors in string theory, using the framework of F-theory. We consider a set of coalesced local 7-branes of a particular Kodaira singularity type and allow s...

Some of the supersymmetric nonlinear sigma models on exceptional groups (E7
or E8) are known to yield almost minimal necessary content of matter fields for
phenomenological model building, including three chiral families and a Higgs
multiplet. We ...

Using the SL(2,R)-duality in a dimensionally reduced spacetime in (the
bosonic sector of) five-dimensional minimal supergravity, we construct general
Kaluza-Klein black hole solutions which carry six independent charges, its
mass, angular momentum...

The dimensional reduction of the bosonic sector of five-dimensional minimal
supergravity to a Lorentzian four-dimensional spacetime leads to a theory with
a massless axion and a dilaton coupled to gravity and two U(1) gauge fields and
the dimensio...

We consider the Gibbons-Hawking metric for a three-dimensional periodic array
of multi-Taub-NUT centers, containing not only centers with a positive NUT
charge but also ones with a negative NUT charge. The latter are regarded as
representing the a...

The dimensional reduction of (the bosonic sector of) five-dimensional minimal
supergravity to four dimensions leads to a theory with a massless axion and a
dilaton coupled to gravity and two U(1) gauge fields (one of which has
Chern-Simons couplin...

We show that the gauge, gravitational (tangent-bundle) and their mixed
anomalies arising from the localized modes near a 5-brane in the SO(32)
heterotic string theory cancel with the anomaly inflow from the bulk with the
use of the Green-Schwarz m...

We show that there exist two 27 and one 27 bar of E6, net one D=4, N=1 chiral
matter supermultiplet as zero modes localized on the intersection of two
5-branes in the E8 x E8 heterotic string theory. The smeared intersecting
5-brane solution is us...

We show that there exist two 27 and one 27bar of E6, net one chiral
supermultiplet as zero modes localized on the intersecting 5-branes in the E8 x
E8 heterotic string theory. A heterotic background is constructed by the
standard embedding in the ...

We consider type II and heterotic string compactifications on an isolated
singularity in the noncompact Gepner model approach. The conifold-type ADE
noncompact Calabi-Yau threefolds, as well as the ALE twofolds, are modeled by a
tensor product of ...

We construct spacetime supersymmetric, modular invariant partition functions
of strings on the conifold-type singularities which include contributions from
the discrete-series representations of SL(2, R). The discrete spectrum is
automatically con...

We study the Lorentz invariance of D=4 and 6 superstrings in the
double-spinor formalism, which are equivalent to the D=4 and 6 superstrings in
the pure-spinor formalism in the sense of the BRST cohomology. We first
re-examine how the conformal an...

We study lower-dimensional superstrings in the double-spinor formalism
introduced by Aisaka and Kazama. These superstrings can be consistently
quantized and are equivalent to the lower-dimensional pure-spinor superstrings
proposed by Grassi and Wy...

We report on progress in determining the complete form of vertex operators
for the IIB matrix model. The exact expressions are obtained for those emitting
massless IIB supergravity fields up to sixth order in the light-cone
superfield, in which th...

We study the zero-dimensional reduced model of D=6 pure super Yang-Mills
theory and argue that the large N limit describes the (2,0) Little String
Theory. The one-loop effective action shows that the force exerted between two
diagonal blocks of ma...

We obtain sets of infinite number of conserved nonlocal charges of strings in
a flat space and pp-wave backgrounds, and compare them before and after
T-duality transformation. In the flat background the set of nonlocal charges is
the same before a...

Motivated by the recent analysis of the E10 sigma model for the study of M
theory, we study a one-dimensional sigma model associated with the hyperbolic
Kac-Moody algebra G2H and its link to D=5, N=2 pure supergravity, which closely
resembles in m...

Unitary 1-matrix models are shown to be exactly equivalent to hermitian
1-matrix models coupled to 2N vectors with appropriate potentials, to all
orders in the 1/N expansion. This fact allows us to use all the techniques
developed and results obta...

We study the gravitational corrections to the F-term in four-dimensional N=1
U(N) gauge theories with flavors, using the Dijkgraaf-Vafa theory. We derive a
compact formula for the annulus contribution in terms of the prime form on the
matrix model...

A hermitian one-matrix model with an even quartic potential exhibits a
third-order phase transition when the cuts of the matrix model curve coalesce.
We use the known solutions of this matrix model to compute effective
superpotentials of an N=1, S...

We show, by direct computations of bosonic string spectra, the O(d,d;Z)
(d=1,2) T-duality in the maximally supersymmetric IIB plane-wave background
compactified on S^1 and T^2. Only half of the ordinary set of zero modes appear
in the Hamiltonian....

We discuss the Green-Schwarz action for type IIB strings in general
plane-wave backgrounds obtained as Penrose limits from any IIB supergravity
solutions with vanishing background fermions. Using the normal-coordinate
expansion in superspace, we p...

The Weyl group symmetry W(E_k) is studied from the points of view of the
E-strings, Painleve equations and U-duality. We give a simple reformulation of
the elliptic Painleve equation in such a way that the hidden symmetry W(E_10)
is manifestly rea...

We examine whether any type II asymmetric orbifolds have the same massless
spectrum as the dimensional reduction of D=5 simple supergravity, which,
besides the eleven-dimensional supergravity, is the only known supergravity
above four dimensions w...

We propose a new prescription of how to represent D-branes in Gepner models
in more general homology classes than those in the previous constructions. The
central role is played by a certain projection acting on the
Recknagel-Schomerus boundary st...

We construct modular invariant partition functions for type II strings on a
conifold and a singular Eguchi-Hanson instanton by means of the SL(2,R)/U(1)
version of Gepner models. In the conifold case, we find an extra massless
hypermultiplet in th...

Extending the seminal work of Bilal and Gervais, we construct a tachyon-free,
modular invariant partition function for critical superstrings on
four-dimensional Minkowski x two-dimensional black hole. This model may be
thought of as an SL(2,R)/U(1...

We give a complete set of generators for the discrete exceptional U-duality
groups of toroidal compactified type II theory and M-theory in d>2. For this,
we use the DSZ quantization in d=4 as originally proposed by Hull and Townsend,
and determine...

It has been known that D=5 simple supergravity resembles D=11 supergravity in
many respects. We present their further resemblances in (1) the duality groups
upon dimensional reduction, and (2) the worldsheet structure of the solitonic
string of th...

We show that any -dimensional strictly stationary, asymptotically
Minkowskian solution of a null reduction of -dimensional pure
gravity must saturate the BPS bound provided that the KK vector field can be
identified appropriatel...

We consider dimensional reduction of the eleven-dimensional supergravity to
less than four dimensions. The three-dimensional nonlinear
sigma model is derived by direct dimensional reduction from eleven dimensions.
In two dimensi...

The non-linear sigma model of the dimensionally reduced Einstein (-Maxwell)
theory is diagonally embedded into that of the two-dimensional heterotic string
theory. Consequently, the embedded string backgrounds satisfy the
(electro-magnetic) Ernst ...

Reinhold W. Gebert, Takeo Inami, Shun'ya Mizoguchi

Int.J.Mod.Phys. A11 (1996) 5479-5493 Mar 1995

We show that the Painlevé test is useful not only for probing
(non-)integrability but also for finding the values of spins of conserved
currents (W currents) in Toda field theories (TFTs). In the case of the TFTs
based on simple Lie algebras t...

We study the Geroch group in the framework of the Ashtekar formulation. In
the case of the one-Killing-vector reduction, it turns out that the third
column of the Ashtekar connection is essentially the gradient of the Ernst
potential, which implie...

Preliminary investigations are made for the stability of the expansion
in three-dimensional gravity coupled to various matter fields, which are
power-counting renormalizable. For unitary matters, a tachyonic pole appears in
the spin-2 part o...

We study the Turaev-Viro invariant as the Euclidean Chern-Simons-Witten
gravity partition function with positive cosmological constant. After
explaining why it can be identified as the partition function of 3-dimensional
gravity, we show that the ...

We study the -deformed su(2) spin network as a 3-dimensional quantum
gravity model. We show that in the semiclassical continuum limit the
Turaev-Viro invariant obtained recently defines naturally regularized
path-integral la Pon...