53,786 research outputs found
MSSM from Ads/CFT
We develop a robust version of the MSSM from a orbifolded AdS/CFT,
with natural low scale unification and briefly discuss cosmology in this
testable model.Comment: 12 pages latex and one eps figur
Massive Superstrings are Black Holes
We argue that it is inconsistent to ignore the gravitational backreaction for
on-shell superstring states at the Planck mass and beyond, and that these
quantum states become Kerr black holes in the classical limit. Consequences are
discussed.Comment: 10 pages, IFP-708-UNC and VAND-TH-94-1
Simplified Renormalizable Model for Tribimaximal Mixing and Cabibbo Angle
In a simplified renormalizable model where the neutrinos have PMNS
(Pontecorvo-Maki-Nakagawa-Sakata) mixings tan and with flavor symmetry there is a
corresponding prediction where the quarks have CKM (Cabibbo-Kobayashi-Maskawa)
mixings tan.Comment: Further typos correcte
The Complexity of the Homotopy Method, Equilibrium Selection, and Lemke-Howson Solutions
We show that the widely used homotopy method for solving fixpoint problems,
as well as the Harsanyi-Selten equilibrium selection process for games, are
PSPACE-complete to implement. Extending our result for the Harsanyi-Selten
process, we show that several other homotopy-based algorithms for finding
equilibria of games are also PSPACE-complete to implement. A further
application of our techniques yields the result that it is PSPACE-complete to
compute any of the equilibria that could be found via the classical
Lemke-Howson algorithm, a complexity-theoretic strengthening of the result in
[Savani and von Stengel]. These results show that our techniques can be widely
applied and suggest that the PSPACE-completeness of implementing homotopy
methods is a general principle.Comment: 23 pages, 1 figure; to appear in FOCS 2011 conferenc
Melt viscosities of lattice polymers using a Kramers potential treatment
Kramers relaxation times and relaxation times and
for the end-to-end distances and for center of mass diffusion are
calculated for dense systems of athermal lattice chains. is defined
from the response of the radius of gyration to a Kramers potential which
approximately describes the effect of a stationary shear flow. It is shown that
within an intermediate range of chain lengths N the relaxation times
and exhibit the same scaling with N, suggesting that N-dependent
melt-viscosities for non-entangled chains can be obtained from the Kramers
equilibrium concept.Comment: submitted to: Journal of Chemical Physic
"Heterotic" Discrete Flavor Model
We present an extended 331 model with discrete flavor symmetry that
simultaneously explains the need to have exactly three generations and provides
acceptable quark and lepton masses and mixings. New fermionic states and gauge
bosons are predicted within the reach of the LHC. We discuss the relevance to
the 126 GeV scalar discovered at the LHC.Comment: 13 pages, v3: version to appear in PR
Switching and Extension of a [c2]Daisy-Chain Dimer Polymer
We report the synthesis of a [c2]daisy-chain dimer via ruthenium-catalyzed ring-closing olefin metathesis. Confirmation of the interlocked nature of the structure was achieved through single-crystal X-ray diffraction analysis. The dimer could be readily switched from the bound to the unbound conformation by treatment with 3.0 equiv of KOH and subsequently reprotonated by treatment with 3.0 equiv of HPF_6. Azide functionalization of the dimer enabled incorporation in linear step-growth polymer chains using the alkyne-azide “click” reaction. Gel permeation chromatography coupled with multiangle laser light scattering analysis showed the polymers contained 22 dimers and had a radius of gyration of 14.8 nm. Acylation of the amines of the dimers sterically forced elongation of the interlocked units, and MALLS analysis of the polymer showed a 48% increase in the R_g (21.4 nm)
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