scholarly journals HALL CONDUCTIVITY ESTIMATES FROM MAGNETOTELLURIC SOUNDING DATA

2020 ◽  
Vol 11 (4) ◽  
pp. 817-828
Author(s):  
V. Plotkin ◽  
V. V. Potapov
Keyword(s):  
Hall Effect ◽  
Normal Wave ◽  
Magnetotelluric Sounding ◽  
Hall Conductivity ◽  
Petroleum Reservoir ◽  
Attenuation Coefficients ◽  
Reservoir Rocks ◽  
Phase Velocities ◽  
Left Circular Polarization ◽  
Semiconductor Properties

Many minerals have semiconductor properties. It is known that petroleum reservoir rocks permeated with hydrocarbon fluids can sometimes behave as semiconductors. In the Earth’s magnetic field, the electrical conductivity of such materials becomes anisotropic, and the Hall effect is quite possible in rocks in natural conditions and detectable by magnetotelluric sounding. In the anisotropic medium, the field is subject to normal mode splitting, and its components show different attenuation coefficients and phase velocities. The modes differ due to polarization and rotation of the field vectors (clockwise in one mode, and counterclockwise in another). With account of the Hall effect, responses of the medium can be different when the medium is excited by a single normal wave. To detect the Hall effect in MTS surveys, we use the polarization analysis method and select the spectra of modes with right and left circular polarization. Special experiments were carried out to detect the contribution of the Hall effect during the MTS surveys. This article presents the first estimates of the Hall conductivity for the studied rocks.

Chiral bosonic field theories and the quantum Hall effect

2001 ◽  
Vol 79 (9) ◽  
pp. 1121-1131 ◽  
Author(s):  
P Bracken
Keyword(s):  
Hall Effect ◽  
Gauge Transformation ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Equation Of Motion ◽  
Hall Conductivity ◽  
Field Theories ◽  
Bosonic Field ◽  
Chern Simons

The gauge-transformation properties of the actions of certain scalar and Chern–Simons theories are investigated, including contributions from the boundary. By imposing chirality constraints on the fields, these types of theories can be used to describe the quantum Hall effect. It is shown that the corresponding equation of motion for the associated current for the theory generates an anomaly, which can be related directly to the Hall conductivity. PACS Nos.: 73.43, 03.70, 11.10, 11.30R

scholarly journals Large Hall and Nernst responses from thermally induced spin chirality in a spin-trimer ferromagnet

2021 ◽  
Vol 118 (33) ◽  
pp. e2023588118
Author(s):  
Kamil K. Kolincio ◽  
Max Hirschberger ◽  
Jan Masell ◽  
Shang Gao ◽  
Akiko Kikkawa ◽  
...  
Keyword(s):  
Hall Effect ◽  
Thermal Fluctuations ◽  
Hall Conductivity ◽  
Strong Response ◽  
Thermally Induced ◽  
Conduction Electrons ◽  
Lattice State ◽  
Ferromagnetic Ordering ◽  
Ordering Transition ◽  
Fundamental Units

The long-range order of noncoplanar magnetic textures with scalar spin chirality (SSC) can couple to conduction electrons to produce an additional (termed geometrical or topological) Hall effect. One such example is the Hall effect in the skyrmion lattice state with quantized SSC. An alternative route to attain a finite SSC is via the spin canting caused by thermal fluctuations in the vicinity of the ferromagnetic ordering transition. Here, we report that for a highly conducting ferromagnet with a two-dimensional array of spin trimers, the thermally generated SSC can give rise to a gigantic geometrical Hall conductivity even larger than the intrinsic anomalous Hall conductivity of the ground state. We also demonstrate that the SSC induced by thermal fluctuations leads to a strong response in the Nernst effect. A comparison of the sign and magnitude of fluctuation–Nernst and Hall responses in fundamental units indicates the need for a momentum–space picture to model these thermally induced signals.

NONCOMMUTATIVE DESCRIPTION OF SPIN HALL EFFECT

2009 ◽  
Vol 06 (02) ◽  
pp. 343-360 ◽  
Author(s):  
AHMED JELLAL ◽  
RACHID HOUÇA
Keyword(s):  
Magnetic Field ◽  
Quantum Mechanics ◽  
Hall Effect ◽  
High Frequency ◽  
Hall Conductivity ◽  
Spin Hall Effect ◽  
Harmonic Oscillators ◽  
Frequency Regime ◽  
Basic Features ◽  
Noncommutative Plane

We propose an approach based on a generalized quantum mechanics to deal with the basic features of the intrinsic spin Hall effect. This can be done by considering two decoupled harmonic oscillators on the noncommutative plane and evaluating the spin Hall conductivity. Focusing on the high frequency regime, we obtain a diagonalized Hamiltonian. After getting the corresponding spectrum, we show that there is a Hall conductivity without an external magnetic field, which is noncommutativity parameter θ-dependent. This allows us to make contact with the spin Hall effect and also give different interpretations. Fixing θ, one can recover three different approaches dealing with the phenomenon.

scholarly journals Current Percolation in Medium with Boundaries under Quantum Hall Effect Conditions

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
M. U. Malakeeva ◽  
V. E. Arkhincheev
Keyword(s):  
Finite Number ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Hall Current ◽  
Quantum Hall ◽  
Singular Points ◽  
Hall Conductivity

The current percolation has been considered in the medium with boundaries under quantum Hall effect conditions. It has been shown that in that case the effective Hall conductivity has a nonzero value due to percolation of the Hall current through the finite number of singular points (in our model these are corners at the phase joints).

WILSON LOOPS AND NON-ABELIAN STATISTICS IN THE QUANTUM HALL EFFECT

1992 ◽  
Vol 06 (17) ◽  
pp. 2875-2891
Author(s):  
MICHAEL STONE
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Conductivity Tensor ◽  
Hall Conductivity ◽  
Wilson Loops ◽  
Many Body ◽  
Quantum Numbers ◽  
The Many ◽  
Chern Simons

There is a topological connection between the boundary excitations of a quantum Hall fluid and the quantum numbers of its vortex-like bulk quasi-particles. I use this connection to examine the group properties of vortex excitations in a generalized quantum Hall fluid, and show how the vortex trajectories become Wilson lines interacting via Chern-Simons fields. As a result, I argue that non-abelian statistics, if they exist, should be independent of the detailed properties of the many-body wavefunction and will depend only on the bulk Hall conductivity tensor.

Laser ablation GC–MS analysis of oil-bearing fluid inclusions in petroleum reservoir rocks

2012 ◽  
Vol 43 ◽  
pp. 20-25 ◽  
Author(s):  
Zhirong Zhang ◽  
Paul Greenwood ◽  
Qu Zhang ◽  
Dan Rao ◽  
Weijun Shi
Keyword(s):  
Laser Ablation ◽  
Fluid Inclusions ◽  
Petroleum Reservoir ◽  
Reservoir Rocks ◽  
Ms Analysis

Effect of Temperature and Frequency on the Acoustic Properties of Konjac Glucomannan-Agar Gels as Tissue Mimicking Materials

2020 ◽  
Vol 307 ◽  
pp. 351-356
Author(s):  
Anis Nazihah Mat Daud ◽  
Md Supar Rohani ◽  
Rosly Jaafar
Keyword(s):  
Soft Tissue ◽  
Konjac Glucomannan ◽  
Acoustic Properties ◽  
Effect Of Temperature ◽  
Attenuation Coefficients ◽  
Phase Velocities ◽  
Agar Gels ◽  
Immersion Technique ◽  
Pulse Echo

In this study, we determine the effect of temperature and frequency on the acoustic properties of konjac glucomannan (KGM)-agar gels to confirm their compatibilities as tissue mimicking materials (TMMs). The acoustic properties of four samples; A (KGM-0.10 g agar), B (KGM-0.20 g agar), C (KGM-0.30 g agar) and D (KGM-0.40 g agar) were measured using pulse echo immersion technique. Findings indicated that the longitudinal velocities of all samples were increased while their attenuation coefficients were decreased as the temperature increased from 27.0 to 37.0°C. It also showed that the phase velocities of all samples were independent to frequency but their attenuation coefficients were increased as the frequency increased from 4.0 to 6.0 MHz. KGM-agar gels are compatible as soft TMMs since their acoustic properties are comparable with the acoustic properties of soft tissue.

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