1,807 research outputs found
Smoking and Social Interaction
We study the social interaction of non-smokers and smokers as a sequential game, incorporating insights from social psychology and experimental economics into an economic model. Social norms a®ect human behavior such that non-smokers do not ask smokers to stop smoking and stay with them, even though disutility from smoking exceeds utility from social interaction. Overall, smoking is unduly often accepted when accommodating smoking is the social norm. The introduction of smoking and non-smoking areas does not overcome this speci¯c ine±ciency. We conclude that smoking bans may represent a required (second-best) policy. smoking policy, health, social norms, guilt aversion, social interactio
Detection of gravitational waves from the QCD phase transition with pulsar timing arrays
If the cosmological QCD phase transition is strongly first order and lasts
sufficiently long, it generates a background of gravitational waves which may
be detected via pulsar timing experiments. We estimate the amplitude and the
spectral shape of such a background and we discuss its detectability prospects.Comment: 7 pages, 5 figs. Version accepted by PR
Gravitational Radiation from Preheating with Many Fields
Parametric resonances provide a mechanism by which particles can be created
just after inflation. Thus far, attention has focused on a single or many
inflaton fields coupled to a single scalar field. However, generically we
expect the inflaton to couple to many other relativistic degrees of freedom
present in the early universe. Using simulations in an expanding
Friedmann-Lema\^itre-Robertson-Walker spacetime, in this paper we show how
preheating is affected by the addition of multiple fields coupled to the
inflaton. We focus our attention on gravitational wave production--an important
potential observational signature of the preheating stage. We find that
preheating and its gravitational wave signature is robust to the coupling of
the inflaton to more matter fields.Comment: 7 pages, 8 figures, v2 submission version, thank you for comments
Neutrino-Nucleus Reactions and Muon Capture in 12C
The neutrino-nucleus cross section and the muon capture rate are discussed
within a simple formalism which facilitates the nuclear structure calculations.
The corresponding formulae only depend on four types of nuclear matrix
elements, which are currently used in the nuclear beta decay. We have also
considered the non-locality effects arising from the velocity-dependent terms
in the hadronic current. We show that for both observables in 12C the higher
order relativistic corrections are of the order of ~5 only, and therefore do
not play a significant role. As nuclear model framework we use the projected
QRPA (PQRPA) and show that the number projection plays a crucial role in
removing the degeneracy between the proton-neutron two quasiparticle states at
the level of the mean field. Comparison is done with both the experimental data
and the previous shell model calculations. Possible consequences of the present
study on the determination of the neutrino oscillation
probability are briefly addressed.Comment: 29 pages, 6 figures, Revtex4. Several changes were made to the
previous manuscript, the results and final conclusions remain unalterable. It
has been accepted for publication as a Regular Article in Physical Review
Non-Markovian large amplitude motion and nuclear fission
The general problem of dissipation in macroscopic large-amplitude collective
motion and its relation to energy diffusion of intrinsic degrees of freedom of
a nucleus is studied. By applying the cranking approach to the nuclear many
body system, a set of coupled dynamical equations for the collective classical
variables and the quantum mechanical occupancies of the intrinsic nuclear
states is derived. Different dynamical regimes of the intrinsic nuclear motion
and its consequences on time properties of collective dissipation are
discussed. The approach is applied to the descant of the nucleus from the
fission barrier.Comment: 9 pages and 3 figure
Searching for gravitational wave burst in PTA data with piecewise linear functions
Transient gravitational waves (aka gravitational wave bursts) within the
nanohertz frequency band could be generated by a variety of astrophysical
phenomena such as the encounter of supermassive black holes, the kinks or cusps
in cosmic strings, or other as-yet-unknown physical processes. Radio-pulses
emitted from millisecond pulsars could be perturbed by passing gravitational
waves, hence the correlation of the perturbations in a pulsar timing array can
be used to detect and characterize burst signals with a duration of
years. We propose a fully Bayesian framework for the
analysis of the pulsar timing array data, where the burst waveform is
generically modeled by piecewise straight lines, and the waveform parameters in
the likelihood can be integrated out analytically. As a result, with merely
three parameters (in addition to those describing the pulsars' intrinsic and
background noise), one is able to efficiently search for the existence and the
sky location of {a burst signal}. If a signal is present, the posterior of the
waveform can be found without further Bayesian inference. We demonstrate this
model by analyzing simulated data sets containing a stochastic gravitational
wave background {and a burst signal generated by the parabolic encounter of two
supermassive black holes.Comment: 13 pages, 10 figure
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