28,781 research outputs found
Coulomb energy and gluon distribution in the presence of static sources
We compute the energy of the ground state and a low lying excitation of the
gluonic field in the presence of static quark -anti-quark (\qq) sources. We
show that for separation between the sources less then a few fm the gluonic
ground state of the static \qq system can be well described in terms of a
mean field wave functional with the excited states corresponding to a single
quasi-particle excitation of the gluon field. We also discuss the role of many
particle excitations relevant for large separation between sources.Comment: 14 pages, 11 figure
Atmospheric Circulation of Exoplanets
We survey the basic principles of atmospheric dynamics relevant to explaining
existing and future observations of exoplanets, both gas giant and terrestrial.
Given the paucity of data on exoplanet atmospheres, our approach is to
emphasize fundamental principles and insights gained from Solar-System studies
that are likely to be generalizable to exoplanets. We begin by presenting the
hierarchy of basic equations used in atmospheric dynamics, including the
Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent
models. We then survey key concepts in atmospheric dynamics, including the
importance of planetary rotation, the concept of balance, and scaling arguments
to show how turbulent interactions generally produce large-scale east-west
banding on rotating planets. We next turn to issues specific to giant planets,
including their expected interior and atmospheric thermal structures, the
implications for their wind patterns, and mechanisms to pump their east-west
jets. Hot Jupiter atmospheric dynamics are given particular attention, as these
close-in planets have been the subject of most of the concrete developments in
the study of exoplanetary atmospheres. We then turn to the basic elements of
circulation on terrestrial planets as inferred from Solar-System studies,
including Hadley cells, jet streams, processes that govern the large-scale
horizontal temperature contrasts, and climate, and we discuss how these
insights may apply to terrestrial exoplanets. Although exoplanets surely
possess a greater diversity of circulation regimes than seen on the planets in
our Solar System, our guiding philosophy is that the multi-decade study of
Solar-System planets reviewed here provides a foundation upon which our
understanding of more exotic exoplanetary meteorology must build.Comment: In EXOPLANETS, edited by S. Seager, to be published in the Spring of
2010 in the Space Science Series of the University of Arizona Press (Tucson,
AZ) (refereed; accepted for publication
The Impact on Maryland\u27s Budget of Allowing Same-Sex Couples to Marry
This analysis estimates the potential impact of extending marriage rights to same-sex couples on Maryland’s state budget. Drawing on data from the U.S. Census Bureau and Maryland statistical reports, we estimate that extending marriage rights to same-sex couples would result in a net gain of approximately $3.2 million each year. This net gain is attributable to savings in expenditures on meanstested public benefit programs and an increase in sales and lodging tax revenue from weddings and wedding-related tourism
Homicide through a Different Lens
This is a pre-copyedited, author-produced version of an article accepted for publication in British Journal of Criminology following peer review. The version of record Morris, P.K. & Graycar, Adam (2011), Homicide through a Different Lens, British Journal of Criminology, Vol. 53, No 5, 823-838 is available online at https://doi.org/10.1093/bjc/azr038.Homicide rates vary across modern societies, yet most scholarly works on homicide are based on studies in developed countries, although, in less developed countries, homicide rates are higher. Homicide is multidimensional and its related social causes and prevalence differ across cultures. In low-homicide countries, most homicides occur as a result of either criminal activity or personal relationship difficulties. This paper highlights that, in one developing country—Jamaica—a different pattern is more common. High homicide rates are connected with partisan politics and neighbourhood social organization. The argument is that neighbourhood social and political factors drive high homicide rates in urban Jamaica
Continuous variable remote state preparation
We extend exact deterministic remote state preparation (RSP) with minimal
classical communication to quantum systems of continuous variables. We show
that, in principle, it is possible to remotely prepare states of an ensemble
that is parameterized by infinitely many real numbers, i.e., by a real
function, while the classical communication cost is one real number only. We
demonstrate continuous variable RSP in three examples using (i) quadrature
measurement and phase space displacement operations, (ii) measurement of the
optical phase and unitaries shifting the same, and (iii) photon counting and
photon number shift.Comment: 7 pages, RevTeX
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Census Snapshot: United States
Using data from the U.S. Census Bureau, this report provides demographic and economic information about same-sex couples and same-sex couples raising children in the U.S. We compare same-sex "unmarried partners," which the Census Bureau defines as an unmarried couple who "shares living quarters and has a close personal relationship," to different-sex married couples in the U.S
Resummation of Large Endpoint Corrections to Color-Octet J/psi Photoproduction
An unresolved problem in J/psi phenomenology is a systematic understanding of
the differential photoproduction cross section, dsigma/dz [gamma + p -> J/psi +
X], where z= E_psi/E_gamma in the proton rest frame. In the non-relativistic
QCD (NRQCD) factorization formalism, fixed-order perturbative calculations of
color-octet mechanisms suffer from large perturbative and nonperturbative
corrections that grow rapidly in the endpoint region, z -> 1. In this paper,
NRQCD and soft collinear effective theory are combined to resum these large
corrections to the color-octet photoproduction cross section. We derive a
factorization theorem for the endpoint differential cross section involving the
parton distribution function and the color-octet J/psi shape functions. A one
loop matching calculation explicitly confirms our factorization theorem at
next-to-leading order. Large perturbative corrections are resummed using the
renormalization group. The calculation of the color-octet contribution to
dsigma/dz is in qualitative agreement with data. Quantitative tests of the
universality of color-octet matrix elements require improved knowledge of shape
functions entering these calculations as well as resummation of the
color-singlet contribution which accounts for much of the total cross section
and also peaks near the endpoint.Comment: 30 pages, 6 figure
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