scholarly journals Viscosities of gluon dominated QGP model within relativistic non-Abelian hydrodynamics

2015 ◽  
Vol 30 (14) ◽  
pp. 1550077 ◽  
Author(s):  
T. P. Djun ◽  
L. T. Handoko ◽  
B. Soegijono ◽  
T. Mart
Keyword(s):  
Shear Viscosity ◽  
Energy Momentum Tensor ◽  
Gluon Plasma ◽  
Equation Of Motion ◽  
Momentum Conservation ◽  
Momentum Tensor ◽  
First Principle ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Energy And Momentum

Based on the first principle calculation, a Lagrangian for the system describing quarks, gluons, and their interactions, is constructed. Ascribed to the existence of dissipative behavior as a consequence of strong interaction within quark–gluon plasma (QGP) matter, auxiliary terms describing viscosities are constituted into the Lagrangian. Through a "kind" of phase transition, gluon field is redefined as a scalar field with four-vector velocity inherently attached. Then, the Lagrangian is elaborated further to produce the energy–momentum tensor of dissipative fluid-like system and the equation of motion (EOM). By imposing the law of energy and momentum conservation, the values of shear and bulk viscosities are analytically calculated. Our result shows that, at the energy level close to hadronization, the bulk viscosity is bigger than shear viscosity. By making use of the conjectured values η/s~1/4π and ζ/s~1, the ratio of bulk to shear viscosity is found to be ζ/η>4π.

Unified DE–DM with diffusive interactions scenario from scalar fields

2017 ◽  
Vol 26 (12) ◽  
pp. 1743021 ◽  
Author(s):  
David Benisty ◽  
E. I. Guendelman
Keyword(s):  
Dark Matter ◽  
Fixed Point ◽  
Energy Momentum Tensor ◽  
Scalar Fields ◽  
Equation Of Motion ◽  
Momentum Conservation ◽  
Momentum Tensor ◽  
Gravitational Energy ◽  
Spacetime Theory ◽  
Energy Momentum Conservation

Generalized models of unified dark matter (DM) and dark energy (DE) in the context of Two Measure Theories and of dynamical spacetime theories are obtained. In Two Measure Theories, one uses metric independent volume elements and this allows to construct unified DM and DE, where the cosmological constant appears as an integration constant associated to the equation of motion of the measure fields. The dynamical spacetime theories generalize the Two Measure Theories by introducing a vector field whose equation of motion guarantees the conservation of a certain energy–momentum tensor, which may be related, but in general is not the same as the gravitational energy–momentum tensor. By considering the dynamical space field appearing in another part of the action (apart from the coupling to the energy–momentum tensor), we can obtain noncovariant energy–momentum conservation. Then, the dynamical spacetime theory becomes a theory of diffusive unified DE and DM. The nonconserved energy–momentum tensors lead at the end to a formulation of interacting DE–DM models in the form of a diffusive type interacting unified DE and DM scenario. We solved analytically the theories for asymptotic solution, and we show that the [Formula: see text]CDM is a fixed point of these theories at large times.

A combined study of thermodynamic and first-principle calculation for single bond energy of Cu clusters

2019 ◽  
Vol 125 (9) ◽  
pp. 094302
Author(s):  
H. Li ◽  
H. N. Du ◽  
X. W. He ◽  
Y. Y. Shen ◽  
H. X. Zhang ◽  
...  
Keyword(s):  
Bond Energy ◽  
First Principle ◽  
Single Bond ◽  
Principle Calculation ◽  
First Principle Calculation

First-Principle Calculation on Misfit Layered Cobaltite and La-Doped Series

2013 ◽  
Vol 652-654 ◽  
pp. 554-558
Author(s):  
Xin Min Min ◽  
Xuchao Wang
Keyword(s):  
Thermoelectric Property ◽  
Variation Method ◽  
First Principle ◽  
Direct Relation ◽  
Discrete Variation ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Binary Oxides ◽  
La Doped ◽  
Layered Cobaltite

The relations between electronic structure and thermoelectric property of misfit layered cobaltite of Ca3Co4O9 and La-doped series are studied from the calculation by density function and discrete variation method (DFT-DVM). The highest valence band (HVB) and the lowest conduction band (LCB) near Fermi level are only mainly from O 2p and Co 3d in Ca2CoO3 layer. Therefore, the semiconductor, or thermoelectric property of Ca3Co4O9 should be mainly from Ca2CoO3 layer, but have no direct relation to the CoO2 layer, which is consistent with that binary oxides hardly have thermoelectric property, but trinary oxide compounds have quite good thermoelectric property. With the amount of La-doped increase, the gap between HVB and LCB firstly decrease, then reaches the minimum, finally increase. The gap affects the thermoelectric property. Therefore, there is a best amount of Na-doped to improve thermoelectric property, which is consistent with the experiment.

First-Principle Calculation of Al2O3(012)/SiC(310) Interface Model

2017 ◽  
Vol 896 ◽  
pp. 120-127 ◽  
Author(s):  
Ting Ting Zhou ◽  
Chuan Zhen Huang ◽  
Ming Dong Yi
Keyword(s):  
Grain Boundary ◽  
Population Analysis ◽  
First Principle ◽  
Interface Model ◽  
Electronic Density ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Multi Phase ◽  
Relationship Of ◽  
Interface Bonding Strength

First-principle calculation is carried out on Al2O3(012)/SiC(310) interface model. It can be concluded from the electronic density and population analysis that Al-C and O-Si located at grain boundary primarily contribute to the interface bonding strength and creep resistance property. The electronic charges in grain boundaries and grains are compared with each other. And the valence electrons are found to be redistributed. The relationship of all kinds of chemical bonds in grains and grain boundary of the interface model is analyzed. Also the toughening mechanism of Al2O3/SiC multi-phase ceramic tool materials is explained in nano-scale.

A Study on First Principle Calculation of Alloy Phase Diagram by Monte Carlo Simulation

1992 ◽  
Vol 291 ◽  
Author(s):  
Hideaki Sawada ◽  
Atsushi Nogami ◽  
Wataru Yamada ◽  
Tooru Matsiuniya
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Alloy Phase Diagram ◽  
Lattice Constant ◽  
Local Concentration ◽  
First Principle ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Local Lattice ◽  
Mc Simulation

ABSTRACTA method of first principle calculation of alloy phase diagram was developed by the combination of first principle energy band calculation, cluster expansion method (CEM) and Monte Carlo (MC) simulation, where the effective multi-body potential energy for the flip test in MC simulation was obtained by the decomposition of the total energy by CEM. This method was applied to Cu-Au binary system. The calculated phase diagram agreed with that of CVM by introducing the dependence of the lattice constant on the concentration of the whole system. Furthermore an attempt of introducing the effect of local lattice relaxation was performed by the consideration of the local concentration. The order-disorder transition temperature became closer to the experimental value by adjustment of the local lattice constant depending on the concentration in the local region consisted of up to the second nearest neighbors of the atom tested for flipping.

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