13,051 research outputs found
Electrical and optical properties of fluid iron from compressed to expanded regime
Using quantum molecular dynamics simulations, we show that the electrical and
optical properties of fluid iron change drastically from compressed to expanded
regime. The simulation results reproduce the main trends of the electrical
resistivity along isochores and are found to be in good agreement with
experimental data. The transition of expanded fluid iron into a nonmetallic
state takes place close to the density at which the constant volume derivative
of the electrical resistivity on internal energy becomes negative. The study of
the optical conductivity, absorption coefficient, and Rosseland mean opacity
shows that, quantum molecular dynamics combined with the Kubo-Greenwood
formulation provides a powerful tool to calculate and benchmark the electrical
and optical properties of iron from expanded fluid to warm dense region
Probability Thermodynamics and Probability Quantum Field
In this paper, we introduce probability thermodynamics and probability
quantum fields. By probability we mean that there is an unknown operator,
physical or nonphysical, whose eigenvalues obey a certain statistical
distribution. Eigenvalue spectra define spectral functions. Various
thermodynamic quantities in thermodynamics and effective actions in quantum
field theory are all spectral functions. In the scheme, eigenvalues obey a
probability distribution, so a probability distribution determines a family of
spectral functions in thermodynamics and in quantum field theory. This leads to
probability thermodynamics and probability quantum fields determined by a
probability distribution. There are two types of spectra: lower bounded
spectra, corresponding to the probability distribution with nonnegative random
variables, and the lower unbounded spectra, corresponding to probability
distributions with negative random variables. For lower unbounded spectra, we
use the generalized definition of spectral functions. In some cases, we
encounter divergences. We remove the divergence by a renormalization procedure.
Moreover, in virtue of spectral theory in physics, we generalize some concepts
in probability theory. For example, the moment generating function in
probability theory does not always exist. We redefine the moment generating
function as the generalized heat kernel, which makes the concept definable when
the definition in probability theory fails. As examples, we construct examples
corresponding to some probability distributions. Thermodynamic quantities,
vacuum amplitudes, one-loop effective actions, and vacuum energies for various
probability distributions are presented
Coalescence of Carbon Atoms on Cu (111) Surface: Emergence of a Stable Bridging-Metal Structure Motif
By combining first principles transition state location and molecular
dynamics simulation, we unambiguously identify a carbon atom approaching
induced bridging metal structure formation on Cu (111) surface, which strongly
modify the carbon atom coalescence dynamics. The emergence of this new
structural motif turns out to be a result of the subtle balance between Cu-C
and Cu-Cu interactions. Based on this picture, a simple theoretical model is
proposed, which describes a variety of surface chemistries very well
Back reaction effects on the imaginary potential of quarkonia in heavy quark cloud
Applying the AdS/CFT correspondence, we investigate the effect of back reaction on the imaginary part of heavy quarkonia potential in strongly coupled N=4 supersymmetric Yang-Mills (SYM) plasma. The back reaction considered here arises from the inclusion of static heavy quarks uniformly distributed over N=4 SYM plasma. It is shown that the presence of back reaction reduces the absolute value of the imaginary potential thus decreasing the thermal width. Furthermore, the results imply that back reaction enhances the quarkonia dissociation
2,3,6,3′,4′-Penta-O-acetyl-4,1′,6′-trichloro-4,1′,6′-trideoxysucrose
In the title compound, C22H29Cl3O13, the glucopyran ring exists in the chair conformation while the glucofuran ring adopts an envelope conformation. Intramolecular C—H⋯O hydrogen bonds occur. In the crystal, adjacent molecules are linked by weak intermolecular C—H⋯O hydrogen bonds
Imaginary potential and entropic force in non-commutative plasma
We study the imaginary potential and entropic force with respect to a heavy quarkonium in non-commutative N=4 super Yang-Mills (SYM) plasma at strong coupling. We compute the two quantities both along commutative as well as the non commutative coordinates of the brane. It is found that the two methods give the same result: non-commutativity reduces quarkonia dissociation
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