24,276 research outputs found
On the mean value of some new sequences
The main purpose of this paper is using the elementary and analytic methods
to study the mean value properties of the Smarandache repetitional sequence, and give two asymptotic formulas for it
Equilibrium Phase Behavior and Maximally Random Jammed State of Truncated Tetrahedra
Systems of hard nonspherical particles exhibit a variety of stable phases
with different degrees of translational and orientational order, including
isotropic liquid, solid crystal, rotator and a variety of liquid crystal
phases. In this paper, we employ a Monte Carlo implementation of the
adaptive-shrinking-cell (ASC) numerical scheme and free-energy calculations to
ascertain with high precision the equilibrium phase behavior of systems of
congruent Archimedean truncated tetrahedra over the entire range of possible
densities up to the maximal nearly space-filling density. In particular, we
find that the system undergoes two first-order phase transitions as the density
increases: first a liquid-solid transition and then a solid-solid transition.
The isotropic liquid phase coexists with the Conway-Torquato (CT) crystal phase
at intermediate densities. At higher densities, we find that the CT phase
undergoes another first-order phase transition to one associated with the
densest-known crystal. We find no evidence for stable rotator (or plastic) or
nematic phases. We also generate the maximally random jammed (MRJ) packings of
truncated tetrahedra, which may be regarded to be the glassy end state of a
rapid compression of the liquid. We find that such MRJ packings are
hyperuniform with an average packing fraction of 0.770, which is considerably
larger than the corresponding value for identical spheres (about 0.64). We
conclude with some simple observations concerning what types of phase
transitions might be expected in general hard-particle systems based on the
particle shape and which would be good glass formers
The Possible J^{PC}=0^{--} Exotic State
In order to explore the possible existence of the exotic state, we
have constructed the tetraquark interpolating operators systematically. As a
byproduct, we notice the tetraquark operators without derivatives do
not exist. The special Lorentz structure of the currents forbids the
four-quark correction to the spectral density. Now the gluon condensate is the
dominant power correction. Within the framework of the finite energy sum rule,
none of the seven interpolating currents supports a resonant signal. Therefore
we conclude that the exotic state does not exist below 2 GeV, which is
consistent with the current experimental observations.Comment: 12 pages, 27 figure
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