2,514 research outputs found
Thermodynamics of the Schwarzschild-AdS black hole with a minimal length
Using the mass-smeared scheme of black holes, we study the thermodynamics of
black holes. Two interesting models are considered. One is the self-regular
Schwarzschild-AdS black hole whose mass density is given by the analogue to
probability densities of quantum hydrogen atoms. The other model is the same
black hole but whose mass density is chosen to be a rational fractional
function of radial coordinates. Both mass densities are in fact analytic
expressions of the -function. We analyze the phase structures of the
two models by investigating the heat capacity at constant pressure and the
Gibbs free energy in an isothermal-isobaric ensemble. Both models fail to decay
into the pure thermal radiation even with the positive Gibbs free energy due to
the existence of a minimal length. Furthermore, we extend our analysis to a
general mass-smeared form that is also associated with the -function,
and indicate the similar thermodynamic properties for various possible
mass-smeared forms based on the -function.Comment: v1: 25 pages, 14 figures; v2: 26 pages, 15 figures; v3: minor
revisions, final version to appear in Adv. High Energy Phy
An adaptive multilevel indexing method for disaster service discovery
With the globe facing various scales of natural disasters then and there, disaster recovery is one among the hottest research areas and the rescue and recovery services can be highly benefitted with the advancements of information and communications technology (ICT). Enhanced rescue effect can be achieved through the dynamic networking of people, systems and procedures. A seamless integration of these elements along with the service-oriented systems can satisfy the mission objectives with the maximum effect. In disaster management systems, services from multiple sources are usually integrated and composed into a usable format in order to effectively drive the decision-making process. Therefore, a novel service indexing method is required to effectively discover desirable services from the large-scale disaster service repositories, comprising a huge number of services. With this in mind, this paper presents a novel multilevel indexing algorithm based on the equivalence theory in order to achieve effective service discovery in large-scale disaster service repositories. The performance and efficiency of the proposed model have been evaluated by both theoretical analysis and practical experiments. The experimental results proved that the proposed algorithm is more efficient for service discovery and composition than existing inverted index methods
An updated determination of the pion-photon transition form factor
In this paper, we study the properties of the pion-photon transition form
factor (TFF), , by using the principle
of maximum commonality (PMC) to deal with its perturbative QCD contribution up
to next-to-next-to-leading order (NNLO) QCD corrections. Applying the PMC, we
achieve precise pQCD approximant for the TFF in large -region without
conventional renormalization scale ambiguity. We also discuss the power
suppressed non-valence quark contribution to the TFF, which is important for a
sound prediction in low and intermediate -region, e.g. the non-valence
quark components affect the TFF by about to when changes
down from to . The resultant pion-photon
TFF shows a better agreement with previous Belle data. It is hoped that
previous discrepancies between the experimental measurements and theoretical
predictions could be clarified by the forth-coming precise data on the Belle II
measurements.Comment: 7 pages, 6 figure
Prompting Large Language Models to Reformulate Queries for Moment Localization
The task of moment localization is to localize a temporal moment in an
untrimmed video for a given natural language query. Since untrimmed video
contains highly redundant contents, the quality of the query is crucial for
accurately localizing moments, i.e., the query should provide precise
information about the target moment so that the localization model can
understand what to look for in the videos. However, the natural language
queries in current datasets may not be easy to understand for existing models.
For example, the Ego4D dataset uses question sentences as the query to describe
relatively complex moments. While being natural and straightforward for humans,
understanding such question sentences are challenging for mainstream moment
localization models like 2D-TAN. Inspired by the recent success of large
language models, especially their ability of understanding and generating
complex natural language contents, in this extended abstract, we make early
attempts at reformulating the moment queries into a set of instructions using
large language models and making them more friendly to the localization models.Comment: 4 pages, 2 figure
An optical clock based on a topological attractor in the polariton superfluid dynamics
We propose an optical polariton clock based on the topologically protected
persistent oscillatory dynamics of a polariton superfluid, which is excited
non-resonantly by a super-Gaussian laser beam in a semiconductor microcavity
containing an external C-shape potential. The persistent oscillations,
characterised by a topological attractor, are based on the dynamical behavior
of small Josephson vortices rotating around the edge of the core of the central
vortex. The clock demonstrates a remarkable stability towards perturbations and
may be tuned by the pump laser intensity to two different frequency ranges:
20.16{\pm}0.14 GHz and 48.4{\pm}1.2 GHz. This clock generator is bistable due
to the chirality of the vortex
Diverse anisotropy of phonon transport in two-dimensional IV-VI compounds: A comparative study
New classes two-dimensional (2D) materials beyond graphene, including layered
and non-layered, and their heterostructures, are currently attracting
increasing interest due to their promising applications in nanoelectronics,
optoelectronics and clean energy, where thermal transport property is one of
the fundamental physical parameters. In this paper, we systematically
investigated the phonon transport properties of 2D orthorhombic group IV-VI
compounds of , , and by solving the Boltzmann transport
equation (BTE) based on first-principles calculations. Despite the similar
puckered (hinge-like) structure along the armchair direction as phosphorene,
the four monolayer compounds possess diverse anisotropic properties in many
aspects, such as phonon group velocity, Young's modulus and lattice thermal
conductivity (), etc. Especially, the along the zigzag and
armchair directions of monolayer shows the strongest anisotropy while
monolayer and shows an almost isotropy in phonon transport. The
origin of the diverse anisotropy is fully studied and the underlying mechanism
is discussed in detail. With limited size, the could be effectively
lowered, and the anisotropy could be effectively modulated by nanostructuring,
which would extend the applications in nanoscale thermoelectrics and thermal
management. Our study offers fundamental understanding of the anisotropic
phonon transport properties of 2D materials, and would be of significance for
further study, modulation and aplications in emerging technologies.Comment: 14 pages, 8 figures, 2 table
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