scholarly journals Hybrid quantum-classical method for simulating high-temperature dynamics of nuclear spins in solids

2018 ◽  
Vol 98 (21) ◽  
Author(s):  
Grigory A. Starkov ◽  
Boris V. Fine
Keyword(s):  
High Temperature ◽  
Classical Method ◽  
Nuclear Spins ◽  
Temperature Dynamics

scholarly journals High Temperature Optical Spectra of Diatomic Molecules at Local Thermodynamic Equilibrium

Atoms ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 67 ◽  
Author(s):  
Robert Beuc ◽  
Mladen Movre ◽  
Goran Pichler
Keyword(s):  
High Temperature ◽  
Thermodynamic Equilibrium ◽  
Bound States ◽  
Local Thermodynamic Equilibrium ◽  
Classical Method ◽  
Rotational Quantum Number ◽  
Computer Time ◽  
Quantum Mechanical ◽  
Theoretical Approaches ◽  
Full Quantum

In the paper, several theoretical approaches to the determination of the reduced absorption and emission coefficients under local thermodynamic equilibrium conditions were exposed and discussed. The full quantum-mechanical procedure based on the Fourier grid Hamiltonian method was numerically robust but time consuming. In that method, all transitions between the bound, free, and quasi-bound states were treated as bound–bound transitions. The semi-classical method assumed continuous energies of ro-vibrational states, so it did not give the ro-vibrational structure of the molecular bands. That approach neglected the effects of turning points but agreed with the averaged-out quantum-mechanical spectra and it was computer time efficient. In the semi-quantum approximation, summing over the rotational quantum number J was done analytically using the classical Franck–Condon principle and the stationary–phase approximation and its consumption of computer time was lower by a few orders of magnitude than the case of the full quantum-mechanical approach. The approximation described well the vibrational but not the rotational structure of the molecular bands. All the above methods were compared and discussed in the case of a visible and near infrared spectrum of LiHe, Li2, and Cs2 molecules in the high temperature range.

scholarly journals STRONG INTERACTION DYNAMICS FROM SPONTANEOUS SYMMETRY BREAKING OF SCALE INVARIANCE

2007 ◽  
Vol 22 (17) ◽  
pp. 1209-1215 ◽  
Author(s):  
E. I. GUENDELMAN
Keyword(s):  
High Temperature ◽  
Simple Model ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Strong Interaction ◽  
Scale Invariance ◽  
Maximal Rank ◽  
Dilaton Field ◽  
Interaction Dynamics ◽  
Temperature Dynamics

Using the mechanism of spontaneous symmetry breaking of scale invariance obtained from the dynamics of maximal rank field strengths, it is possible to spontaneously generate confining behavior. Introducing a dilaton field, the study of nontrivial confining and de-confining transitions appears possible. This is manifest in two ways at least: One can consider bags which contain an unconfined phase in the internal region and a confined phase outside and also one obtains a simple model for deconfinement at high temperature from the finite temperature dynamics of the dilaton field.

High-Temperature Dynamics, High-Speed Modulation, and Transmission Experiments Using 1.3- $\mu\hbox{m}$ InGaAs Single-Mode VCSELs

2007 ◽  
Vol 25 (9) ◽  
pp. 2791-2798 ◽  
Author(s):  
E. Soderberg ◽  
J.S. Gustavsson ◽  
P. Modh ◽  
A. Larsson ◽  
Zhenzhong Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Single Mode ◽  
Speed Modulation ◽  
Temperature Dynamics ◽  
High Speed Modulation

Formation Mechanism of AlZrO and ZrAlON Phases in Al-ZrO2-N2 Systems

2010 ◽  
Vol 150-151 ◽  
pp. 1234-1238
Author(s):  
Rong Lin Wang ◽  
Jia Lin Sun ◽  
Jing Long Bu ◽  
Zhi Fa Wang
Keyword(s):  
Mass Transfer ◽  
High Temperature ◽  
Gas Phase ◽  
Formation Mechanism ◽  
Raw Materials ◽  
Contact Reaction ◽  
Intermediate Phases ◽  
N2 Atmosphere ◽  
Temperature Dynamics

Al-ZrO2 composites were sintered in N2 atmosphere at 1000 oC, 1100 oC, 1200 oC and 1300 oC with ZrO2 and Al powders as raw materials. Formation mechanism of AlZrO and ZrAlON phases in Al-ZrO2-N2 systems were investigated by TG-DTA, XRD, SEM and EDS analyses. Results showed there existed new phases of ZrAl3O3N and AlxZr1-xO2-0.5x beside ZrO, ZrN, Al2O3, AlN and intermediate phases of Al7O3N5, Al8O3N6, ZrON, ZrON2, Zr7O8N4 in samples sintered at 1000 oC to 1300 oC. There existed process of mass transfer of ZrO2 in gas phase in samples at high temperature. Dynamics processes of ZrAl3O3N and AlxZr1-xO2-0.5x phases formed in N2 atmosphere at high temperature included contact reaction and ZrAlON sosoloid crystallization.

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