13,638 research outputs found
The Quantum Echo of the Early Universe
We show that the fluctuations of quantum fields as seen by late comoving
observers are significantly influenced by the history of the early Universe,
and therefore they transmit information about the nature of spacetime in
timescales when quantum gravitational effects were non-negligible. We discuss
how this may be observable even nowadays, and thus used to build falsifiability
tests of quantum gravity theories.Comment: 3 pages. 2 Figures. Proceedings Theory Canada 9. Published in
Canadian Journal of Physics.
(http://www.nrcresearchpress.com/doi/abs/10.1139/cjp-2014-0567
Violation of the strong Huygen's principle and timelike signals from the early Universe
We analyze the implications of the violations of the strong Huygens principle
in the transmission of information from the early universe to the current era
via massless fields. We show that much more information reaches us through
timelike channels (not mediated by real photons) than it is carried by rays of
light, which are usually regarded as the only carriers of information.Comment: 5 pages, 2 figures. RevTeX 4.1. V2: Updated to match published
version. Previous title "A glimpse of the early universe without real light"
modified to match Physical Review Letters published versio
Diffuse interstellar bands {\lambda}5780 and {\lambda}5797 in the Antennae Galaxy as seen by MUSE
ABRIDGED: Diffuse interstellar bands (DIBs) are faint spectral absorption
features of unknown origin. Research on DIBs beyond the Local Group (LG) will
surely blossom in the era of the ELTs. A possibility that needs to be explored
is the use of integral field spectrographs. We do so by using MUSE data for the
Antennae Galaxy, the closest major galaxy merger. High S-to-N spectra were
created by co-adding the signal of many spatial elements. The emission of the
underlying stellar population was modeled using STARLIGHT. To our knowledge, we
have derived the first maps for the DIBs at l5780 and l5797 in galaxies outside
the LG. The l5780 DIB was detected in an area of ~0.6 arcmin2, corresponding to
a linear scale of ~25 kpc2. This region was sampled using >200 independent
lines of sight. The DIB l5797 was detected in >100 independent lines of sight.
Both DIBs are associated with a region with high emission in the HI 21 cm line,
implying a connection between atomic gas and DIBs, as the correlations for the
Milky Way also suggest. Conversely, there is mild spatial association between
the two DIBs and the molecular gas, in agreement with results for our Galaxy
that indicate a lack of correlation between DIBs and molecular gas. The overall
structure for the DIB strength distribution and extinction are comparable.
Within the system, the l5780 DIB clearly correlates with the extinction. Both
DIBs follow the relationship between equivalent width and reddening when data
for several galaxies are considered. Unidentified Infrared emission Bands
(UIBs, likely caused by PAHs) and the l5780 and l5797 DIBs show similar but not
identical spatial distributions. We attribute the differences to extinction
effects without necessarily implying a radically different nature of the
respective carriers. The results illustrate the enormous potential of integral
field spectrographs for extragalactic DIB research.Comment: 12 pages, 13 figures, accepted by Astronomy & Astrophysics; version
corrected by English edito
On the strategic choice of spatial price policy: the role of the pricing game rules.
The strategic choice of spatial price policy under duopoly crucially depends on the rules of price competition. We show that under simultaneous price competition and under leader-follower price competition (with the discriminatory firm being the leader), the pricing policy game is not, as stated by Thisse and Vives (1988), a Prisoner's Dilemma.
Global fit to transitions
We perform a general model-independent analysis of transitions, including measurements of ,
, their differential distributions, the recently
measured longitudinal polarization , and constraints from the
lifetime, each of which has significant impact on
the fit. A global fit to a general set of Wilson coefficients of an effective
low-energy Hamiltonian is presented, the solutions of which are interpreted in
terms of hypothetical new-physics mediators. From the obtained results we
predict selected observables, such as the baryonic
transition , the ratio
, the forward-backward asymmetries , the polarization asymmetries
, and the longitudinal polarization fraction
. The latter shows presently a slight tension with any new-physics
model, such that an improved measurement could have an important impact. We
also discuss the potential change due the very recently announced preliminary
measurement by the Belle collaboration.Comment: 47 pages, 12 figures. Version published at JHE
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