2,995 research outputs found
A Memetic Algorithm for the Multidimensional Assignment Problem
The Multidimensional Assignment Problem (MAP or s-AP in the case of s
dimensions) is an extension of the well-known assignment problem. The most
studied case of MAP is 3-AP, though the problems with larger values of s have
also a number of applications. In this paper we propose a memetic algorithm for
MAP that is a combination of a genetic algorithm with a local search procedure.
The main contribution of the paper is an idea of dynamically adjusted
generation size, that yields an outstanding flexibility of the algorithm to
perform well for both small and large fixed running times. The results of
computational experiments for several instance families show that the proposed
algorithm produces solutions of very high quality in a reasonable time and
outperforms the state-of-the art 3-AP memetic algorithm.Comment: 14 page
Interacting new agegraphic Phantom model of dark energy in non-flat universe
In this paper we consider the new agegraphic model of interacting dark energy
in non-flat universe. We show that the interacting agegraphic dark energy can
be described by a phantom scalar field. Then we show this phantomic description
of the agegraphic dark energy and reconstruct the potential of the phantom
scalar field.Comment: 8 pages, no figur
Interacting Three Fluid System and Thermodynamics of the Universe Bounded by the Event Horizon
The work deals with the thermodynamics of the universe bounded by the event
horizon. The matter in the universe has three constituents namely dark energy,
dark matter and radiation in nature and interaction between then is assumed.
The variation of entropy of the surface of the horizon is obtained from unified
first law while matter entropy variation is calculated from the Gibbss' law.
Finally, validity of the generalized second law of thermodynamics is examined
and conclusions are written point wise.Comment: 7 page
Weak Gravity Conjecture for Noncommutative Field Theory
We investigate the weak gravity bounds on the U(1) gauge theory and scalar
field theories in various dimensional noncommutative space. Many results are
obtained, such as the upper bound on the noncommutative scale for
four dimensional noncommutative U(1) gauge theory. We also discuss the weak
gravity bounds on their commutative counterparts. For example, our result on 4
dimensional noncommutative U(1) gauge theory reduces in certain limit to its
commutative counterpart suggested by Arkani-Hamed et.al at least at tree-level.Comment: 9 page
Statefinder diagnostic and stability of modified gravity consistent with holographic and new agegraphic dark energy
Recently one of us derived the action of modified gravity consistent with the
holographic and new-agegraphic dark energy. In this paper, we investigate the
stability of the Lagrangians of the modified gravity as discussed in [M. R.
Setare, Int. J. Mod. Phys. D 17 (2008) 2219; M. R. Setare, Astrophys. Space
Sci. 326 (2010) 27]. We also calculate the statefinder parameters which
classify our dark energy model.Comment: 12 pages, 2 figures, accepted by Gen. Relativ. Gravi
Some Low Dimensional Evidence for the Weak Gravity Conjecture
We discuss a few examples in 2+1 dimensions and 1+1 dimensions supporting a
recent conjecture concerning the relation between the Planck scale and the
coupling strength of a non-gravitional interaction, unlike those examples in
3+1 dimensions, we do not have to resort to exotic physics such as small black
holes. However, the result concerning these low dimensional examples is a
direct consequence of the 3+1 dimensional conjecture.Comment: 7 pages, harvma
Holographic dark energy with time varying parameter
We consider the holographic dark energy model in which the model parameter
evolves slowly with time. First we calculate the evolution of EoS
parameter as well as the deceleration parameter in this generalized version of
holographic dark energy (GHDE). Depending on the parameter , the phantom
regime can be achieved earlier or later compare with original version of
holographic dark energy. The evolution of energy density of GHDE model is
investigated in terms of parameter . We also show that the time-dependency
of can effect on the transition epoch from decelerated phase to
accelerated expansion. Finally, we perform the statefinder diagnostic for GHDE
model and show that the evolutionary trajectories of the model in plane
are strongly depend on the parameter .Comment: 16 pages, 4 figures, accepted by Astrophys Space Sc
Achieving Conformational Control in RTP and TADF Emitters by Functionalization of the Central Core
Three new symmetrical donor–acceptor–donor (D–A–D)-type molecules were prepared with phenothiazine (PTZ) as electron donors and 9,9-dimethylthioxanthene (TX) as the electron acceptor. The PTZ groups are attached at different positions on the acceptor core – ortho or meta to the sulfur of TX. The molecules have been characterized by X-ray crystallography, in-depth photophysical studies and theoretical calculations. This series provides new insights into how molecular functionalization and intramolecular charge transfer determines the singlet-triplet gap ΔEST. Two of the molecules have weak D/A decoupling and a relatively large ΔEST of 0.52 eV which prohibits the upconversion of triplet excitons to the singlet state, showing strong room temperature phosphorescence (RTP). When the TX acceptor strength is enhanced by the attachment of benzoyl substituents a very small ΔEST of <0.01 eV is observed. In this case excitons in the triplet state can be efficiently upconverted to the singlet state via reverse intersystem crossing (RISC) resulting in thermally activated delayed fluorescence (TADF). TADF and RTP are unambiguously assigned by distinctive photophysical data, notably a comparison of degassed and aerated luminescence spectra, temperature-dependent time-resolved fluorescence decays and power dependence of the intensity of delayed emission (for the TADF emitter)
A Weak Gravity Conjecture for Scalar Field Theories
We show that the recently proposed weak gravity conjecture\cite{AMNV0601} can
be extended to a class of scalar field theories. Taking gravity into account,
we find an upper bound on the gravity interaction strength, expressed in terms
of scalar coupling parameters. This conjecture is supported by some
two-dimensional models and noncommutative field theories.Comment: version published in JHE
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