13,270 research outputs found
Three-Point Functions at Finite Temperature
We study 3-point functions at finite temperature in the closed time path
formalism. We give a general decomposition of the eight component tensor in
terms of seven vertex functions. We derive a spectral representation for these
seven functions in terms of two independent real spectral functions. We derive
relationships between the seven functions and obtain a representation of the
vertex tensor that greatly simplifies calculations in real time.Comment: 21 pages LaTeX; one ps-figure; Revised version, contains more
references and discussio
Evaporation Prescription for Time-Dependent Density Functional Calculations
Collisions between Cm and Ca are systematically calculated by
time-dependent density functional calculations with evaporation prescription.
Depending on the incident energy and impact parameter, fusion, fusion-fission,
and quasi-fission events are expected to appear. In this paper, the evaporation
prescription is introduced, which is expected to be rather important to
heavy-ion reactions producing superheavy nuclei, where the heavier total mass
can be related to the higher total excitation energy.Comment: To appear in the NN2012 Proceedings in Journal of Physics: Conference
Series; revised based on the referee's comment (ver. 2, 09/2012
Elliptic flow of thermal photons and dileptons
In this talk we describe the recently discovered rich phenomenology of
elliptic flow of electromagnetic probes of the hot matter created in
relativistic heavy-ion collisions. Using a hydrodynamic model for the
space-time dynamics of the collision fireball created in Au+Au collisions at
RHIC, we compute the transverse momentum spectra and elliptic flow of thermal
photons and dileptons. These observables are shown to provide differential
windows into various stages of the fireball expansion.Comment: 8 pages, including 9 figures. Invited talk at the Hard Probes 2006
Conference (Asilomar, June 9-16, 2006), to appear in the Proceedings
(Elsevier
Stability of quasi-linear hyperbolic dissipative systems
In this work we want to explore the relationship between certain eigenvalue
condition for the symbols of first order partial differential operators
describing evolution processes and the linear and nonlinear stability of their
stationary solutions.Comment: 16 pages, Te
Four-Point Spectral Functions and Ward Identities in Hot QED
We derive spectral representations for the different components of the
4-point function at finite temperature in the real time formalism in terms of
five real spectral densities. We explicitly calculate all these functions in
QED in the hard thermal loop approximation. The Ward identities obeyed by the
1-loop 3- and 4-point functions in real time and their spectral functions are
derived. We compare our results with those derived previously in the
imaginary-time formalism for retarded functions in hot QCD, and we discuss the
generalization of our results to non-equilibrium situations.Comment: 16 pages in Revtex with 3 figures, dense version, a typo correcte
Radial flow afterburner for event generators and the baryon puzzle
A simple afterburner including radial flow to the randomized transverse
momentum obtained from event generators, Pythia and Hijing, has been
implemented to calculate the ratios and compare them with available
data. A coherent trend of qualitative agreement has been obtained in
collisions and in for various centralities. Those results indicate that
the radial flow does play an important role in the so called baryon puzzle
anomaly.Comment: 11 pages, 5 figures. To appear in Journal of Physics
Shock heating by FR I radio sources in galaxy clusters
Feedback by active galactic nuclei (AGN) is frequently invoked to explain the
cut-off of the galaxy luminosity function at the bright end and the absence of
cooling flows in galaxy clusters. Meanwhile, there are recent observations of
shock fronts around radio-loud AGN. Using realistic 3D simulations of jets in a
galaxy cluster, we address the question what fraction of the energy of active
galactic nuclei is dissipated in shocks. We find that weak shocks that
encompass the AGN have Mach numbers of 1.1-1.2 and dissipate at least 2% of the
mechanical luminosity of the AGN. In a realistic cluster medium, even a
continuous jet can lead to multiple shock structures, which may lead to an
overestimate of the AGN duty cycles inferred from the spatial distribution of
waves.Comment: accepted by MNRAS Letter
A systematic comparison of jet quenching in different fluid-dynamical models
Comparing four different (ideal and viscous) hydrodynamic models for the
evolution of the medium created in 200 AGeV Au-Au collisions, combined with two
different models for the path length dependence of parton energy loss, we study
the effects of jet quenching on the emission-angle dependence of the nuclear
suppression factor R_AA(phi) and the away-side per trigger yield I_AA(phi).
Each hydrodynamic model was tuned to provide a reasonable description of the
single-particle transverse momentum spectra for all collision centralities, and
the energy loss models were adjusted to yield the same pion nuclear suppression
factor in central Au-Au collisions. We find that the experimentally measured
in-plane vs. out-of-plane spread in R_AA(phi) is better reproduced by models
that shift the weight of the parton energy loss to later times along its path.
Among the models studied here, this is best achieved by energy loss models that
suppress energy loss at early times, combined with hydrodynamic models that
delay the dilution of the medium density due to hydrodynamic expansion by
viscous heating. We were unable to identify a clear tomographic benefit of a
measurement of I_AA(phi) over that of R_AA(phi).Comment: 17 pages, 11 figure
Psychopharmacological Procedures
Psychopharmacology has opened the door to many previously blocked parts of psychiatric therapy. It has been a welcome catalyst for a long awaited rapprochement between psychiatry and the rest of medicine. Even if psychopharmacological research is not likely to produce another revolutionary breakthrough type of drug in the near future, there is good reason to expect many more useful therapeutic tools to issue from such research in the years to come
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