scholarly journals Thermoelectric Relations in the Conformal Limit in Dirac and Weyl Semimetals

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 814
Author(s):  
Vicente Arjona ◽  
Juan Borge ◽  
María A. H. Vozmediano
Keyword(s):  
Chemical Potential ◽  
Transport Coefficients ◽  
Three Dimensional ◽  
Anomalous Behavior ◽  
Conformal Anomaly ◽  
Electronic Systems ◽  
Electric Transport ◽  
Thermo Electric ◽  
Weyl Semimetals ◽  
Band Crossing

Dirac and Weyl semimetals are three-dimensional electronic systems with the Fermi level at or near a band crossing. Their low energy quasi-particles are described by a relativistic Dirac Hamiltonian with zero effective mass, challenging the standard Fermi liquid (FL) description of metals. In FL systems, electrical and thermo–electric transport coefficient are linked by very robust relations. The Mott relation links the thermoelectric and conductivity transport coefficients. In a previous publication, the thermoelectric coefficient was found to have an anomalous behavior originating in the quantum breakdown of the conformal anomaly by electromagnetic interactions. We analyze the fate of the Mott relation in the system. We compute the Hall conductivity of a Dirac metal as a function of the temperature and chemical potential and show that the Mott relation is not fulfilled in the conformal limit.

scholarly journals Critical behaviour of hydrodynamic series

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
M. Asadi ◽  
H. Soltanpanahi ◽  
F. Taghinavaz
Keyword(s):  
Chemical Potential ◽  
Transport Coefficients ◽  
Hydrodynamic Modes ◽  
Third Order ◽  
Hydrodynamic Mode ◽  
Strongly Coupled ◽  
Conformal Theory ◽  
Shear Dispersion ◽  
Type Iib String Theory ◽  
Hydrodynamic Transport

Abstract We investigate the time-dependent perturbations of strongly coupled $$ \mathcal{N} $$ N = 4 SYM theory at finite temperature and finite chemical potential with a second order phase transition. This theory is modelled by a top-down Einstein-Maxwell-dilaton description which is a consistent truncation of the dimensional reduction of type IIB string theory on AdS5×S5. We focus on spin-1 and spin-2 sectors of perturbations and compute the linearized hydrodynamic transport coefficients up to the third order in gradient expansion. We also determine the radius of convergence of the hydrodynamic mode in spin-1 sector and the lowest non-hydrodynamic modes in spin-2 sector. Analytically, we find that all the hydrodynamic quantities have the same critical exponent near the critical point θ = $$ \frac{1}{2} $$ 1 2 . Moreover, we propose a relation between symmetry enhancement of the underlying theory and vanishing of the only third order hydrodynamic transport coefficient θ1, which appears in the shear dispersion relation of a conformal theory on a flat background.

scholarly journals Exploring the Partonic Phase at Finite Chemical Potential in and out-of Equilibrium

Particles ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 178-192 ◽  
Author(s):  
O. Soloveva ◽  
P. Moreau ◽  
L. Oliva ◽  
V. Voronyuk ◽  
V. Kireyeu ◽  
...  
Keyword(s):  
Cross Sections ◽  
Chemical Potential ◽  
Transport Coefficients ◽  
Gluon Plasma ◽  
Entropy Density ◽  
Baryon Chemical Potential ◽  
Equilibrium Study ◽  
200 Gev ◽  
Quasiparticle Model ◽  
Scattering Cross Sections

We study the influence of the baryon chemical potential μ B on the properties of the Quark–Gluon–Plasma (QGP) in and out-of equilibrium. The description of the QGP in equilibrium is based on the effective propagators and couplings from the Dynamical QuasiParticle Model (DQPM) that is matched to reproduce the equation-of-state of the partonic system above the deconfinement temperature T c from lattice Quantum Chromodynamics (QCD). We study the transport coefficients such as the ratio of shear viscosity η and bulk viscosity ζ over entropy density s, i.e., η / s and ζ / s in the ( T , μ ) plane and compare to other model results available at μ B = 0 . The out-of equilibrium study of the QGP is performed within the Parton–Hadron–String Dynamics (PHSD) transport approach extended in the partonic sector by explicitly calculating the total and differential partonic scattering cross sections based on the DQPM and the evaluated at actual temperature T and baryon chemical potential μ B in each individual space-time cell where partonic scattering takes place. The traces of their μ B dependences are investigated in different observables for symmetric Au + Au and asymmetric Cu + Au collisions such as rapidity and m T -distributions and directed and elliptic flow coefficients v 1 , v 2 in the energy range 7.7 GeV ≤ s N N ≤ 200 GeV.

Experimental and simulation study of impurity transport response to RMPs in RF-heated H-mode plasmas at EAST

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Germán Vogel ◽  
Hongming Zhang ◽  
Yongcai Shen ◽  
Shuyu Dai ◽  
Youwen Sun ◽  
...  
Keyword(s):  
Inner Core ◽  
Extreme Ultraviolet ◽  
Transport Coefficients ◽  
Three Dimensional ◽  
Line Emission ◽  
Core Region ◽  
Emission Mitigation ◽  
One Dimensional ◽  
Impurity Transport ◽  
Transport Code

Spatial profiles of impurity emission measurements in the extreme ultraviolet (EUV) spectroscopic range in radiofrequency (RF)-heated discharges are combined with one-dimensional and three-dimensional transport simulations to study the effects of resonant magnetic perturbations (RMPs) on core impurity accumulation at EAST. The amount of impurity line emission mitigation by RMPs appears to be correlated with the ion Z for lithium, carbon, iron and tungsten monitored, i.e. stronger suppression of accumulation for heavier ions. The targeted effect on the most detrimental high-Z impurities suggests a possible advantage using RMPs for impurity control. Profiles of transport coefficients are calculated with the STRAHL one-dimensional impurity transport code, keeping $\nu /D$ fixed and using the measured spatial profiles of $\textrm{F}{\textrm{e}^{20 + }}$ , $\textrm{F}{\textrm{e}^{21 + }}$ and $\textrm{F}{\textrm{e}^{22 + }}$ to disentangle the transport coefficients. The iron diffusion coefficient ${D_{\textrm{Fe}}}$ increases from $1.0- 2.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ to $1.5- 3.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ from the core region to the edge region $(\rho \gt 0.5)$ after the onset of RMPs. Meanwhile, an inward pinch of iron convective velocity ${\nu _{\textrm{Fe}}}$ decreases in magnitude in the inner core region and increases significantly in the outer confined region, simultaneously contributing to preserving centrally peaked $\textrm{Fe}$ profiles and exhausting the impurities. The ${D_{\textrm{Fe}}}$ and ${\nu _{\textrm{Fe}}}$ variations lead to reduced impurity contents in the plasma. The three-dimensional edge impurity transport code EMC3-EIRENE was also applied for a case of RMP-mitigated high-Z accumulation at EAST and compared to that of low-Z carbon. The exhaust of ${\textrm{C}^{6 + }}$ toward the scrape-off layer accompanying an overall suppression of heavier ${\textrm{W}^{30 + }}$ is observed when using RMPs.

Theory of ultrasonic attenuation in one and two dimensional metals

1976 ◽  
Vol 54 (14) ◽  
pp. 1454-1460 ◽  
Author(s):  
T. Tiedje ◽  
R. R. Haering
Keyword(s):  
Ultrasonic Attenuation ◽  
Three Dimensional ◽  
Electronic Systems ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
One Dimensional ◽  
The Difference

The theory of ultrasonic attenuation in metals is extended so that it applies to quasi one and two dimensional electronic systems. It is shown that the attenuation in such systems differs significantly from the well-known results for three dimensional systems. The difference is particularly marked for one dimensional systems, for which the attenuation is shown to be strongly temperature dependent.

Three-dimensional quantum Hall effect in Weyl and double-Weyl semimetals

2018 ◽  
Vol 382 (44) ◽  
pp. 3205-3210
Author(s):  
Zhi-Peng Gao ◽  
Zhi Li ◽  
Dan-Wei Zhang
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Three Dimensional ◽  
Weyl Semimetals

scholarly journals Hydrodynamic magneto-transport in holographic charge density wave states

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Andrea Amoretti ◽  
Daniel Areán ◽  
Daniel K. Brattan ◽  
Luca Martinoia
Keyword(s):  
Black Hole ◽  
Transport Coefficients ◽  
Density Wave ◽  
Thermo Electric ◽  
Hydrodynamic Description ◽  
Dc Conductivities ◽  
Analytic Expressions ◽  
Wave States ◽  
Hole Geometry ◽  
Gauge Gravity

Abstract We employ hydrodynamics and gauge/gravity to study magneto-transport in phases of matter where translations are broken (pseudo-)spontaneously. First we provide a hydrodynamic description of systems where translations are broken homogeneously at nonzero lattice pressure and magnetic field. This allows us to determine analytic expressions for all the relevant transport coefficients. Next we construct holographic models of those phases and determine all the DC conductivities in terms of the dual black hole geometry. Combining the hydrodynamic and holographic descriptions we obtain analytic expression for the AC thermo-electric correlators. These are fixed in terms of the black hole geometry and a pinning frequency we determine numerically. We find an excellent agreement between our hydrodynamic and holographic descriptions and show that the holographic models are good avatars for the study of magneto-phonons.

scholarly journals Irradiated three-dimensional Luttinger semimetal: A factory for engineering Weyl semimetals

2018 ◽  
Vol 97 (20) ◽  
Author(s):  
Sayed Ali Akbar Ghorashi ◽  
Pavan Hosur ◽  
Chin-Sen Ting
Keyword(s):  
Three Dimensional ◽  
Weyl Semimetals

scholarly journals Generation of a Nernst Current from the Conformal Anomaly in Dirac and Weyl Semimetals

2018 ◽  
Vol 120 (20) ◽  
Author(s):  
M. N. Chernodub ◽  
Alberto Cortijo ◽  
María A. H. Vozmediano
Keyword(s):  
Conformal Anomaly ◽  
Weyl Semimetals

scholarly journals Formation of Three-Dimensional Electronic Networks Using Axially Ligated Metal Phthalocyanines as Stable Neutral Radicals

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 747
Author(s):  
Ryoya Sato ◽  
Masaki Matsuda
Keyword(s):  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Charge Carriers ◽  
Electronic Systems ◽  
Metal Phthalocyanine ◽  
Molecular Conductors ◽  
Metal Phthalocyanines ◽  
X Ray ◽  
Electronic Networks ◽  
Electrical Resistivities

Organic π-radical crystals are potential single-component molecular conductors, as they involve charge carriers. We fabricated new organic π-radical crystals using axially ligated metal phthalocyanine anions ([MIII(Pc)L2]−) as starting materials. Electrochemical oxidation of [MIII(Pc)L2]− afforded single crystals of organic π-radicals of the type MIII(Pc)Cl2·THF (M = Co or Fe, THF = tetrahydrofuran), where the π-conjugated macrocyclic phthalocyanine ligand is one-electron oxidized. The X-ray crystal structure analysis revealed that MIII(Pc)Cl2 formed three-dimensional networks with π-π overlaps. The electrical resistivities of CoIII(Pc)Cl2·THF and FeIII(Pc)Cl2·THF at room temperature along the a-axis were 6 × 102 and 6 × 103 Ω cm, respectively, and were almost isotropic, meaning that MIII(Pc)Cl2·THF had three-dimensional electronic systems.

Binding Energies and Linear and Nonlinear Optical Properties of a Donor Impurity in a Three-Dimensional Quantum Pseudodot

2013 ◽  
Vol 68 (12) ◽  
pp. 744-750 ◽  
Author(s):  
Muharrem Kirak ◽  
Sait Yilmaz
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Chemical Potential ◽  
Refractive Index Change ◽  
Three Dimensional ◽  
Great Influence ◽  
Binding Energies ◽  
Nonlinear Optical Properties ◽  
Hydrogenic Impurity ◽  
Mass Approximation

A theoretical study of the electronic properties of the ground state and excited states and the linear and the third-order nonlinear optical properties (i. e., absorption coefficients and refractive indices) in a spherical GaAs pseudodot system is reported. The variational procedure has been employed in determining sublevel energy eigenvalues and their wave functions within the effective mass approximation. Our results indicate that the chemical potential of the electron gas and the minimum value of the pseudoharmonic potential have a great influence on the electrical and optical properties of hydrogenic impurity states. Also, we have found that the magnitudes of the absorption coefficient and the refractive index change of the spherical quantum dot increase for transitions between higher levels.

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