103,215 research outputs found
Recommended from our members
Willingness to Pay for Brand Reputation: Lessons from the Volkswagen Diesel Emissions Scandal
In this study, we use the announcement of the Volkswagen emissions scandalon September 18, 2015, as an exogenous shock to measure consumers’ willing-ness to pay (WTP) for brand reputation. Only Volkswagen diesel cars producedin2009-2015were announced as emissions violators. Using eBay car auction data,we estimate the impacts of the scandal on the prices of Volkswagen emissionsnon-violatingcars. Our difference-in-differences estimates show that final bid prices decreased by 14% and 9% in diesel and gasoline car markets, respectively, whichpurely reflected a decline in consumers’ WTP for Volkswagen’s brand reputation.Additionally, the difference in price-drops between the violating and non-violating diesel cars is statistically insignificant. This may be due to the fact that consumers rationally adjust their WTP by expecting compensation which will almost surely be provided by Volkswagen for violating models
The Grassmannian Sigma Model in SU(2) Yang-Mills Theory
Spin-charge separation in pure SU(2) Yang-Mills theory was recently found to
involve the dynamics of an O(3) non-linear sigma model and, seemingly, a
Grassmannian non-linear sigma model. In this article we explicitly construct
the Grassmannian sigma model of the form appearing in the the spin-charge
separated SU(2) theory through a quaternionic decomposition of the manifold,
thus verifying its relevance in this context. The coupling between this model
and the O(3) non-linear sigma model is further commented upon.Comment: 11 pages, undergraduate research project; version published in J.
Phys.
Eta-nucleon coupling constant in QCD with SU(3) symmetry breaking
We study the NN coupling constant using the method of QCD sum rules
starting from the vacuum-to-eta correlation function of the interpolating
fields of two nucleons. The matrix element of this correlation has been taken
with respect to nucleon spinors to avoid unwanted pole contribution. The
SU(3)-flavor symmetry breaking effects have been accounted for via the
-mass, s-quark mass and eta decay constant to leading order. Out of the
four sum rules obtained by taking the ratios of the two sum rules in
conjunction with the two sum rules in nucleon mass, three are found to give
mutually consistent results. We find the SU(3) breaking effects significant, as
large as 50% of the SU(3) symmetric part.Comment: 13 pages, 12 figure
Comment on "Two Phase Transitions in the Fully frustrated XY Model"
The conclusions of a recent paper by Olsson (Phys. Rev. Lett. 75, 2758
(1995), cond-mat/9506082) about the fully frustrated XY model in two dimensions
are questioned. In particular, the evidence presented for having two separate
chiral and U(1) phase transitions are critically considered.Comment: One page one table, to Appear in Physical Review Letter
Prescribed pattern transformation in swelling gel tubes by elastic instability
We present a study on swelling-induced circumferential buckling of tubular
shaped gels. Inhomogeneous stress develops as gel swells under mechanical
constraints, which gives rise to spontaneous buckling instability without
external force. Full control over the post-buckling pattern is experimentally
demonstrated. A simple analytical model is developed using elastic energy to
predict stability and post-buckling patterns upon swelling. Analysis reveals
that height to diameter ratio is the most critical design parameter to
determine buckling pattern, which agrees well with experimental and numerical
results.Comment: 32 pages, 7 figure
The role of the dopant in the superconductivity of diamond
We present an {\it ab initio} study of the recently discovered
superconductivity of boron doped diamond within the framework of a
phonon-mediated pairing mechanism. The role of the dopant, in substitutional
position, is unconventional in that half of the coupling parameter
originates in strongly localized defect-related vibrational modes, yielding a
very peaked Eliashberg function. The electron-phonon
coupling potential is found to be extremely large and T is limited by the
low value of the density of states at the Fermi level
Anomalous tunneling conductances of a spin singlet \nu=2/3 edge states: Interplay of Zeeman splitting and Long Range Coulomb Interaction
The point contact tunneling conductance between edges of the spin singlet
quantum Hall states is studied both in the
quasiparticle tunneling picture and in the electron tunneling picture. Due to
the interplay of Zeeman splitting and the long range Coulomb interaction
between edges of opposite chirality novel spin excitations emerge, and their
effect is characterized by anomalous exponents of the charge and spin tunneling
conductances in various temperature ranges. Depending on the kinds of
scatterings at the point contact and the tunneling mechanism the anomalous
interaction in spin sector may enhance or suppress the tunneling conductances.
The effects of novel spin excitation are also relevant to the recent NMR
experiments on quantum Hall edges.Comment: Revtex File, 7 pages: To be published in Physical Reviews
- …