17,738 research outputs found
Mirror Symmetry of Calabi-Yau Supermanifolds
We study super Landau-Ginzburg mirrors of the weighted projective superspace
WCP^{3|2} which is a Calabi-Yau supermanifold and appeared in
hep-th/0312171(Witten) in the topological B-model. One of them is an elliptic
fibration over the complex plane whose coordinate is given in terms of two
bosonic and two fermionic variables as well as Kahler parameter of WCP^{3|2}.
The other is some patch of a degree 3 Calabi-Yau hypersurface in CP^2 fibered
by the complex plane whose coordinate depends on both above four variables and
Kahler parameter but its dependence behaves quite differently.Comment: 12pp; the last paragraph of section 1 improved and some
clarifications adde
Quantum N=2 super Algebra In Superspace
We discuss the N=2 extension of Polyakov-Bershadsky algebra with
the generic central charge, , at the quantum level in superspace. It
contains, in addition to the spin 1 N=2 stress tensor, the spins
bosonic and spins fermionic supercurrents satisfying the first class
nonlinear chiral constraints. In the limit, the ``classical''
N=2 algebra is recovered.Comment: 8 pages, LaTeX, name of the first author extende
Perturbing Around A Warped Product Of AdS_4 and Seven-Ellipsoid
We compute the spin-2 Kaluza-Klein modes around a warped product of AdS_4 and
a seven-ellipsoid. This background with global G_2 symmetry is related to a
U(N) x U(N) N=1 superconformal Chern-Simons matter theory with sixth order
superpotential. The mass-squared in AdS_4 is quadratic in G_2 quantum number
and KK excitation number. We determine the dimensions of spin-2 operators using
the AdS/CFT correspondence. The connection to N=2 theory preserving SU(3) x
U(1)_R is also discussed.Comment: 21pp; The second and last paragraphs of section 2, the footnotes 1
and 2 added and to appear in JHE
Geometrically Induced Phase Transitions at Large N
Utilizing the large N dual description of a metastable system of branes and
anti-branes wrapping rigid homologous S^2's in a non-compact Calabi-Yau
threefold, we study phase transitions induced by changing the positions of the
S^2's. At leading order in 1/N the effective potential for this system is
computed by the planar limit of an auxiliary matrix model. Beginning at the two
loop correction, the degenerate vacuum energy density of the discrete confining
vacua split, and a potential is generated for the axion. Changing the relative
positions of the S^2's causes discrete jumps in the energetically preferred
confining vacuum and can also obstruct direct brane/anti-brane annihilation
processes. The branes must hop to nearby S^2's before annihilating, thus
significantly increasing the lifetime of the corresponding non-supersymmetric
vacua. We also speculate that misaligned metastable glueball phases may
generate a repulsive inter-brane force which stabilizes the radial mode present
in compact Calabi-Yau threefolds.Comment: 47 pages, 7 figure
Phonons in Nanocrystalline 57Fe
We measured the phonon density of states (DOS) of nanocrystalline Fe by resonant inelastic nuclear γ-ray scattering. The nanophase material shows large distortions in its phonon DOS. We attribute the high energy distortion to lifetime broadening. A damped harmonic oscillator model for the phonons provides a low quality factor, Qu, averaging about 5, but the longitudinal modes may have been broadened most. The nanocrystalline Fe also shows an enhancement in its phonon DOS at energies below 15 meV. The difference in vibrational entropy of the bulk and nanocrystalline Fe was small, owing to competing changes in the nanocrystalline phonon DOS at low and high energies
Complete Nondiagonal Reflection Matrices of RSOS/SOS and Hard Hexagon Models
In this paper we compute the most general nondiagonal reflection matrices of
the RSOS/SOS models and hard hexagon model using the boundary Yang-Baxter
equations. We find new one-parameter family of reflection matrices for the RSOS
model in addition to the previous result without any parameter. We also find
three classes of reflection matrices for the SOS model, which has one or two
parameters. For the hard hexagon model which can be mapped to RSOS(5) model by
folding four RSOS heights into two, the solutions can be obtained similarly
with a main difference in the boundary unitarity conditions. Due to this, the
reflection matrices can have two free parameters. We show that these extra
terms can be identified with the `decorated' solutions. We also generalize the
hard hexagon model by `folding' the RSOS heights of the general RSOS(p) model
and show that they satisfy the integrability conditions such as the Yang-
Baxter and boundary Yang-Baxter equations. These models can be solved using the
results for the RSOS models.Comment: 18pages,Late
More on Meta-Stable Brane Configuration
We describe the intersecting brane configuration of type IIA string theory
corresponding to the meta-stable nonsupersymmetric vacua in four dimensional
N=1 supersymmetric SU(N_c) gauge theory with an antisymmetric flavor, a
conjugate symmetric flavor, eight fundamental flavors, m_f fundamental flavors
and m_f antifundamental flavors. This is done by analyzing the N=1
supersymmetric SU(2m_f-N_c+4) magnetic gauge theory with dual matters and the
corresponding dual superpotential.Comment: 20 pp, 3 figures; Pages 11,12, and 14 improved; to appear in CQ
N=8 SCFT and M Theory on AdS_4 x RP^7
We study M theory on AdS_4 \times \RP^7 corresponding to 3 dimensional
superconformal field theory which is the strong coupling limit of
3 dimensional super Yang-Mills theory. For SU(N) theory, a wrapped M5 brane on
\RP^5 can be interpreted as baryon vertex. For theory, by
using the property of (co-)homology of \RP^7, we classify various wrapping
branes and consider domain walls and the baryon vertex.Comment: 17 pages, Changed baryon like operator as M5 branes in M theory
rather than D6 brane in IIA theory. To appear in Phys.Rev.
In situ real-time analysis of alloy film composition and segregation dynamics with parallel detection reflection electron energy loss spectroscopy
Real-time measurements of GexSi1 – x/Si(001) composition and segregation dynamics in Sn/Si(001) in molecular beam epitaxy are demonstrated using parallel detection reflection electron energy loss spectroscopy. Parallel detection enables quantitative acquisition of low-loss spectra in a time of < 500 µs and surface composition determination in GexSi1 – x/Si(001) via Ge L2,3 core loss analysis to a precision of approximately 2% in time of order 1 s. Segregation and trapping kinetics of monolayer thickness Sn films during Si epitaxy on Sn-covered Si(100) has also been studied using the Sn M4.5 core loss
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