53,322 research outputs found
New estimates of the hybrid US Phillips curve
This paper examines the validity of Rudd and Whelan’s (2006) critiques of Gali and Gertler’s (1999) hybrid Phillips curve (HYPC) by re-estimating the HYPC using full information maximum likelihood (FIML). We also estimate HYPC with the constraint that the weights for the sum of forward looking and backward looking expectations should be unity. Our results support Rudd and Whelan’s conclusion that the weight for forward looking expectations is insignificant.New Keynesian Phillips Curve, Price Rigidities, FIML Estimation
SUSY Dark Matter In Light Of CDMS/XENON Limits
In this talk we briefly review the current CDMS/XENON constraints on the
neutralino dark matter in three popular supersymmetric models: the minimal
(MSSM), the next-to-minimal (NMSSM) and the nearly minimal (nMSSM). The
constraints from the dark matter relic density and various collider experiments
are also taken into account. The conclusion is that for each model the current
CDMS/XENON limits can readily exclude a large part of the parameter space
allowed by other constraints and the future SuperCDMS or XENON100 can cover
most of the allowed parameter space. The implication for the Higgs search at
the LHC is also discussed. It is found that in the currently allowed parameter
space the MSSM charged Higgs boson is quite unlikely to be discovered at the
LHC while the neutral Higgs bosons and may be accessible at the LHC in
the parameter space with a large parameter.Comment: talk given at 2nd International Workshop on Dark Matter, Dark Energy
and Matter-Antimatter Asymmetry, Nov 5-6, 2010, Hsinchu, Taiwan (to appear in
Int. J. Mod. Phys. D
Control of coherent backscattering by breaking optical reciprocity
Reciprocity is a universal principle that has a profound impact on many areas
of physics. A fundamental phenomenon in condensed-matter physics, optical
physics and acoustics, arising from reciprocity, is the constructive
interference of quantum or classical waves which propagate along time-reversed
paths in disordered media, leading to, for example, weak localization and
metal-insulator transition. Previous studies have shown that such coherent
effects are suppressed when reciprocity is broken. Here we show that by
breaking reciprocity in a controlled manner, we can tune, rather than simply
suppress, these phenomena. In particular, we manipulate coherent backscattering
of light, also known as weak localization. By utilizing a non-reciprocal
magneto-optical effect, we control the interference between time-reversed paths
inside a multimode fiber with strong mode mixing, and realize a continuous
transition from the well-known peak to a dip in the backscattered intensity.
Our results may open new possibilities for coherent control of classical and
quantum waves in complex systemsComment: Comments are welcom
On the Entropy Function and the Attractor Mechanism for Spherically Symmetric Extremal Black Holes
In this paper we elaborate on the relation between the entropy formula of
Wald and the "entropy function" method proposed by A. Sen. For spherically
symmetric extremal black holes, it is shown that the expression of extremal
black hole entropy given by A. Sen can be derived from the general entropy
definition of Wald, without help of the treatment of rescaling the AdS_2 part
of near horizon geometry of extremal black holes. In our procedure, we only
require that the surface gravity approaches to zero, and it is easy to
understand the Legendre transformation of f, the integration of Lagrangian
density on the horizon, with respect to the electric charges. Since the Noether
charge form can be defined in an "off-shell" form, we define a corresponding
entropy function, with which one can discuss the attractor mechanism for
extremal black holes with scalar fields.Comment: v3: Revtex4, 19 pages, discussion added, mistakes corrected, final
version; to appear in Phys. Rev.
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