6,540 research outputs found
Holographic Van der Waals phase transition for a hairy black hole
The Van der Waals(VdW) phase transition in a hairy black hole is investigated
by analogizing its charge, temperature, and entropy as the temperature,
pressure, and volume in the fluid respectively. The two point correlation
function(TCF), which is dual to the geodesic length, is employed to probe this
phase transition. We find the phase structure in the temperaturegeodesic
length plane resembles as that in the temperaturethermal entropy plane
besides the scale of the horizontal coordinate. In addition, we find the equal
area law(EAL) for the first order phase transition and critical exponent of the
heat capacity for the second order phase transition in the
temperaturegeodesic length plane are consistent with that in
temperaturethermal entropy plane, which implies that the TCF is a good probe
to probe the phase structure of the back hole.Comment: Accepted by Advances in High Energy Physics(The special issue:
Applications of the Holographic Duality to Strongly Coupled Quantum Systems
The Advantage of Playing Home in NBA: Microscopic, Team-Specific and Evolving Features
The idea that the success rate of a team increases when playing home is
broadly accepted and documented for a wide variety of sports. Investigations on
the so-called home advantage phenomenon date back to the 70's and every since
has attracted the attention of scholars and sport enthusiasts. These studies
have been mainly focused on identifying the phenomenon and trying to correlate
it with external factors such as crowd noise and referee bias. Much less is
known about the effects of home advantage in the microscopic dynamics of the
game (within the game) or possible team-specific and evolving features of this
phenomenon. Here we present a detailed study of these previous features in the
National Basketball Association (NBA). By analyzing play-by-play events of more
than sixteen thousand games that span thirteen NBA seasons, we have found that
home advantage affects the microscopic dynamics of the game by increasing the
scoring rates and decreasing the time intervals between scores of teams playing
home. We verified that these two features are different among the NBA teams,
for instance, the scoring rate of the Cleveland Cavaliers team is increased
0.16 points per minute (on average the seasons 2004-05 to 2013-14) when playing
home, whereas for the New Jersey Nets (now the Brooklyn Nets) this rate
increases in only 0.04 points per minute. We further observed that these
microscopic features have evolved over time in a non-trivial manner when
analyzing the results team-by-team. However, after averaging over all teams
some regularities emerge; in particular, we noticed that the average
differences in the scoring rates and in the characteristic times (related to
the time intervals between scores) have slightly decreased over time,
suggesting a weakening of the phenomenon.Comment: Accepted for publication in PLoS ON
The Distribution of the Asymptotic Number of Citations to Sets of Publications by a Researcher or From an Academic Department Are Consistent With a Discrete Lognormal Model
How to quantify the impact of a researcher's or an institution's body of work
is a matter of increasing importance to scientists, funding agencies, and
hiring committees. The use of bibliometric indicators, such as the h-index or
the Journal Impact Factor, have become widespread despite their known
limitations. We argue that most existing bibliometric indicators are
inconsistent, biased, and, worst of all, susceptible to manipulation. Here, we
pursue a principled approach to the development of an indicator to quantify the
scientific impact of both individual researchers and research institutions
grounded on the functional form of the distribution of the asymptotic number of
citations. We validate our approach using the publication records of 1,283
researchers from seven scientific and engineering disciplines and the chemistry
departments at the 106 U.S. research institutions classified as "very high
research activity". Our approach has three distinct advantages. First, it
accurately captures the overall scientific impact of researchers at all career
stages, as measured by asymptotic citation counts. Second, unlike other
measures, our indicator is resistant to manipulation and rewards publication
quality over quantity. Third, our approach captures the time-evolution of the
scientific impact of research institutions.Comment: 20 pages, 11 figures, 3 table
Wannier-Stark localization in one-dimensional amplitude-chirped lattices
We study the Wannier-Stark (WS) localization in one-dimensional
amplitude-chirped lattices with the th onsite potential modulated by a
function , where is the external field with a period
determined by ( and are co-prime integers). In the
Hermitian (or non-Hermitian) systems with real (or imaginary) fields, we can
obtain real (or imaginary) WS ladders in the eigenenergy spectrum. In most
cases with , there are multiple WS ladders with all the eigenstates
localized in the strong field limit. However, in the lattices with , the
energy-dependent localization phenomenon emerges due to the competition between
spatially periodic and linearly increasing behaviors in the onsite potential.
About half the number of eigenstates are gathered at the band center and can
extend over a wide region or even the full range of the lattice, even when the
field becomes very strong. Moreover, in the non-Hermitian lattices with odd
, some of the WS ladders become doubly degenerate, where the eigenstates are
evenly distributed at two neighboring sites in a wide regime of field strength.
Our work opens an avenue for exploring WS localization in both Hermitian and
non-Hermitian amplitude-chirped lattices.Comment: 6 pages, 6 figure
Thermodynamics and weak cosmic censorship conjecture of the torus-like black hole
After studying the energy-momentum relation of charged particles'
Hamilton-Jacobi equations, we discuss the laws of thermodynamics and the weak
cosmic censorship conjecture in torus-like black holes. We find that both the
first law of thermodynamic as well as the weak cosmic censorship conjecture are
valid in both the normal phase space and extended phase space. However, the
second law of thermodynamics is only valid in the normal phase space. Our
results show that the first law and weak cosmic censorship conjecture do not
depend on the phase spaces while the second law depends. What's more, we find
that the shift of the metric function that determines the event horizon take
the same form in different phase spaces, indicating that the weak cosmic
censorship conjecture is independent of the phase space.Comment: 15 page
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