scholarly journals Graphene’s non-equilibrium fermions reveal Doppler-shifted magnetophonon resonances accompanied by Mach supersonic and Landau velocity effects

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. T. Greenaway ◽  
P. Kumaravadivel ◽  
J. Wengraf ◽  
L. A. Ponomarenko ◽  
A. I. Berdyugin ◽  
...  
Keyword(s):  
Monolayer Graphene ◽  
Lattice Vibrations ◽  
Two Dimensional ◽  
Supersonic Speed ◽  
Atomic Lattice ◽  
Fermion Systems ◽  
Transverse Acoustic ◽  
Far From Equilibrium ◽  
Quantum Phenomena ◽  
Non Equilibrium

AbstractOscillatory magnetoresistance measurements on graphene have revealed a wealth of novel physics. These phenomena are typically studied at low currents. At high currents, electrons are driven far from equilibrium with the atomic lattice vibrations so that their kinetic energy can exceed the thermal energy of the phonons. Here, we report three non-equilibrium phenomena in monolayer graphene at high currents: (i) a “Doppler-like” shift and splitting of the frequencies of the transverse acoustic (TA) phonons emitted when the electrons undergo inter-Landau level (LL) transitions; (ii) an intra-LL Mach effect with the emission of TA phonons when the electrons approach supersonic speed, and (iii) the onset of elastic inter-LL transitions at a critical carrier drift velocity, analogous to the superfluid Landau velocity. All three quantum phenomena can be unified in a single resonance equation. They offer avenues for research on out-of-equilibrium phenomena in other two-dimensional fermion systems.

Tunable optical vortex array in a two-dimensional electromagnetically induced atomic lattice

2021 ◽  
Author(s):  
jinpeng Yuan ◽  
Hengfei ZHANG ◽  
Chaohua Wu ◽  
lirong wang ◽  
liantuan xiao ◽  
...  
Keyword(s):  
Optical Vortex ◽  
Two Dimensional ◽  
Atomic Lattice ◽  
Vortex Array

scholarly journals Energy loss by fast-travelling charged particles traversing two-dimensional materials

2020 ◽  
Vol 233 ◽  
pp. 03005
Author(s):  
Jaime E. Santos ◽  
Mikhail Vasilevskiy ◽  
Nuno M.R. Peres ◽  
Antti-Pekka Jauho
Keyword(s):  
Thin Films ◽  
Energy Loss ◽  
2D Materials ◽  
Charged Particles ◽  
Monolayer Graphene ◽  
Two Dimensional ◽  
Particle Detection ◽  
Hydrodynamic Approximation ◽  
Radiation Losses ◽  
Two Dimensional Materials

We consider the problem of the radiation losses by fast-traveling particles traversing two-dimensional (2d) materials or thin films. After review¬ing the screening of electromagnetic fields by two dimensional conducting ma¬terials, we obtain the energy loss by a fast particle traversing such a material or film. In particular, we discuss the pattern of radiation emitted by monolayer graphene treated within a hydrodynamic approximation. These results are com¬pared with recent published results using similar approximations and, having in mind a potential application to particle detection, we briefly discuss how one can improve on the signals obtained by using other two-dimensional materials.

scholarly journals Non-Equilibrium Ionization in Puppis A

1983 ◽  
Vol 101 ◽  
pp. 245-252
Author(s):  
P. F. Winkler ◽  
C. R. Canizares ◽  
B. C. Bromley
Keyword(s):  
High Resolution ◽  
Spectroscopic Data ◽  
Supernova Remnant ◽  
Optical Data ◽  
Equilibrium Conditions ◽  
X Ray ◽  
Flux Measurements ◽  
Far From Equilibrium ◽  
Einstein Observatory ◽  
Non Equilibrium

High resolution X-ray spectroscopy of the brightest knot of emission in the Puppis A supernova remnant shows that it is made up of ionizing plasma, far from equilibrium. Flux measurements in several X-ray lines enable us to determine the non-equilibrium conditions: electron temperature, ion populations, and time since the knot was heated by the supernova shock. Imaging and spectroscopic data from the Einstein Observatory together suggest that this knot is a cloud of density about 10 cm−3 which has recently been shocked to a temperature 7 × 106 K. Radio and optical data on the region appear consistent with this picture.

Application of Steepest-Entropy-Ascent Quantum Thermodynamics to Predicting Heat and Mass Diffusion From the Atomistic Up to the Macroscopic Level

2015 ◽  
Author(s):  
Guanchen Li ◽  
Michael R. von Spakovsky
Keyword(s):  
Spatial Scales ◽  
Local Equilibrium ◽  
Phenomenological Approach ◽  
Heat Diffusion ◽  
Quantum Thermodynamics ◽  
Macroscopic Property ◽  
State Evolution ◽  
Equilibrium Process ◽  
Far From Equilibrium ◽  
Non Equilibrium

Conventional first principle approaches for studying non-equilibrium or far-from-equilibrium processes all depend on the mechanics of individual particles or quantum states and as a result, require too many details of the mechanical features of the system to easily or even practically arrive at the value of a macroscopic property. In contrast, thermodynamics, which has been extremely successful in the stable equilibrium realm, provides an approach for determining a macroscopic property without going into the mechanical details. Nonetheless, such a phenomenological approach is not generally applicable to a non-equilibrium process except in the near-equilibrium realm and under the limiting local equilibrium and continuum assumptions, both of which prevent its application across all scales. To address these drawbacks, steepest-entropy-ascent quantum thermodynamics (SEAQT) can be used. It provides an ensemble-based, thermodynamics, first principles approach applicable to the entire non-equilibrium realm even that far-from-equilibrium and does so with a single kinematics and dynamics able to cross all temporal and spatial scales. Based on prior developments by the authors, this paper applies SEAQT to the study of mass and heat diffusion. Specifically, the study focuses on the thermodynamic features of far-from-equilibrium state evolution. Two kinds of size effects on the evolution trajectory, i.e., concentration and volume effects, are discussed.

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