431 research outputs found
Large N reduction on coset spaces
As an extension of our previous work concerning the large N reduction on
group manifolds, we study the large N reduction on coset spaces. We show that
large N field theories on coset spaces are described by certain corresponding
matrix models. We also construct Chern-Simons-like theories on group manifolds
and coset spaces, and give their reduced models.Comment: 22 pages, typos correcte
Gauge-Higgs Unification and Quark-Lepton Phenomenology in the Warped Spacetime
In the dynamical gauge-Higgs unification of electroweak interactions in the
Randall-Sundrum warped spacetime the Higgs boson mass is predicted in the range
120 GeV -- 290 GeV, provided that the spacetime structure is determined at the
Planck scale. Couplings of quarks and leptons to gauge bosons and their
Kaluza-Klein (KK) excited states are determined by the masses of quarks and
leptons. All quarks and leptons other than top quarks have very small couplings
to the KK excited states of gauge bosons. The universality of weak interactions
is slightly broken by magnitudes of , and for
-, - and -, respectively. Yukawa couplings become
substantially smaller than those in the standard model, by a factor |\cos
\onehalf \theta_W| where is the non-Abelian Aharonov-Bohm phase
(the Wilson line phase) associated with dynamical electroweak symmetry
breaking.Comment: 34 pages, 7 eps files, comments and a reference adde
Large-N reduction for N=2 quiver Chern-Simons theories on S^3 and localization in matrix models
We study reduced matrix models obtained by the dimensional reduction of N=2
quiver Chern-Simons theories on S^3 to zero dimension and show that if a
reduced model is expanded around a particular multiple fuzzy sphere background,
it becomes equivalent to the original theory on S^3 in the large-N limit. This
is regarded as a novel large-N reduction on a curved space S^3. We perform the
localization method to the reduced model and compute the free energy and the
vacuum expectation value of a BPS Wilson loop operator. In the large-N limit,
we find an exact agreement between these results and those in the original
theory on S^3.Comment: 46 pages, 11 figures; minor modification
Quantifying and Controlling Prethermal Nonergodicity in Interacting Floquet Matter
The use of periodic driving for synthesizing many-body quantum states depends crucially on the existence of a prethermal regime, which exhibits drive-tunable properties while forestalling the effects of heating. This dependence motivates the search for direct experimental probes of the underlying localized nonergodic nature of the wave function in this metastable regime. We report experiments on a many-body Floquet system consisting of atoms in an optical lattice subjected to ultrastrong sign-changing amplitude modulation. Using a double-quench protocol, we measure an inverse participation ratio quantifying the degree of prethermal localization as a function of tunable drive parameters and interactions. We obtain a complete prethermal map of the drive-dependent properties of Floquet matter spanning four square decades of parameter space. Following the full time evolution, we observe sequential formation of two prethermal plateaux, interaction-driven ergodicity, and strongly frequency-dependent dynamics of long-time thermalization. The quantitative characterization of the prethermal Floquet matter realized in these experiments, along with the demonstration of control of its properties by variation of drive parameters and interactions, opens a new frontier for probing far-from-equilibrium quantum statistical mechanics and new possibilities for dynamical quantum engineering
T-duality, Fiber Bundles and Matrices
We extend the T-duality for gauge theory to that on curved space described as
a nontrivial fiber bundle. We also present a new viewpoint concerning the
consistent truncation and the T-duality for gauge theory and discuss the
relation between the vacua on the total space and on the base space. As
examples, we consider S^3(/Z_k), S^5(/Z_k) and the Heisenberg nilmanifold.Comment: 24 pages, typos correcte
N=4 Super Yang-Mills from the Plane Wave Matrix Model
We propose a nonperturbative definition of N=4 super Yang-Mills (SYM). We
realize N=4 SYM on RxS^3 as the theory around a vacuum of the plane wave matrix
model. Our regularization preserves sixteen supersymmetries and the gauge
symmetry. We perform the 1-loop calculation to give evidences that the
superconformal symmetry is restored in the continuum limit.Comment: 39 pages, 6 figures, some sentences are improved, references added,
typos corrected, version to appear in PR
Bone Morphogenetic Protein-6 (BMP-6) induces atresia in goat primordial follicles cultured in vitro
Heterozygote Advantage for Fecundity
Heterozygote advantage, or overdominance, remains a popular and persuasive explanation for the maintenance of genetic variation in natural populations in the face of selection. However, despite being first proposed more than 80 years ago, there remain few examples that fit the criteria for heterozygote advantage, all of which are associated with disease resistance and are maintained only in the presence of disease or other gene-by-environment interaction. Here we report five new examples of heterozygote advantage, based around polymorphisms in the BMP15 and GDF9 genes that affect female fecundity in domesticated sheep and are not reliant on disease for their maintenance. Five separate mutations in these members of the transforming growth factor β (TGFβ) superfamily give phenotypes with fitness differentials characteristic of heterozygous advantage. In each case, one copy of the mutant allele increases ovulation rate, and ultimately litter size per ewe lambing, relative to the wildtype. However, homozygous ewes inheriting mutant alleles from both parents have impaired oocyte development and maturation, which results in small undeveloped ovaries and infertility. Using data collected over many years on ovulation rates, litter size, and lambing rates, we have calculated the equilibrium solution for each of these polymorphisms using standard population genetic theory. The predicted equilibrium frequencies obtained for these mutant alleles range from 0.11 to 0.23, which are amongst the highest yet reported for a polymorphism maintained by heterozygote advantage. These are amongst the most frequent and compelling examples of heterozygote advantage yet described and the first documented examples of heterozygote advantage that are not reliant on a disease interaction for their maintenance
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