The Experts below are selected from a list of 187437 Experts worldwide ranked by ideXlab platform
K A Matveev - One of the best experts on this subject based on the ideXlab platform.
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transport properties of partially Equilibrated quantum wires
Physical Review B, 2010Co-Authors: Tobias Micklitz, Jerome Rech, K A MatveevAbstract:We study the effect of thermal equilibration on the transport properties of a weakly interacting one-dimensional electron system. Although equilibration is severely suppressed due to phase-space restrictions and conservation laws, it can lead to intriguing signatures in partially Equilibrated quantum wires. We consider an ideal homogeneous quantum wire. At finite temperature we find a correction to the quantized conductance, which for a short wire scales with its length, but saturates in the limit of an infinitely long wire. We also discuss thermoelectric properties of long quantum wires. We show that the uniform quantum wire is a perfect thermoelectric refrigerator, approaching Carnot efficiency with increasing wire length.
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Conductance of fully Equilibrated quantum wires
Physical Review Letters, 2009Co-Authors: Jerome Rech, Tobias Micklitz, K A MatveevAbstract:We study the conductance of a quantum wire in the presence of weak electron-electron scattering. In a sufficiently long wire the scattering leads to full equilibration of the electron distribution function in the frame moving with the electric current. At non-zero temperature this equilibrium distribution differs from the one supplied by the leads. As a result the contact resistance increases, and the quantized conductance of the wire acquires a quadratic in temperature correction. The magnitude of the correction is found by analysis of the conservation laws of the system and does not depend on the details of the interaction mechanism responsible for equilibration.
Y D Afanasyev - One of the best experts on this subject based on the ideXlab platform.
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zonal jets in equilibrating baroclinic instability on the polar beta plane experiments with altimetry
Journal of Geophysical Research, 2015Co-Authors: Anna Magdalena Matulka, Y D AfanasyevAbstract:Results from the laboratory experiments on the evolution of baroclinically unstable flows generated in a rotating tank with topographic β-effect are presented. We study zonal jets of alternating direction which occur in these flows. The primary system we model includes lighter fluid in the South and heavier fluid in the North with resulting slow meridional circulation and fast mean zonal motion. In a two-layer system, the velocity shear between the layers results in baroclinic instability which Equilibrates with time and, due to interaction with β-effect generates zonal jets. This system is archetypal for various geophysical systems including the general circulation and jet streams in the Earth's atmosphere, the Antarctic Circumpolar Current, or the areas in the vicinity of western boundary currents where baroclinic instability and multiple zonal jets are observed. The gradient of the surface elevation and the thickness of the upper layer are measured in the experiments using the Altimetric Imaging Velocimetry and the Optical Thickness Velocimetry techniques, respectively. Barotropic and baroclinic velocity fields are then derived from the measured quantities. The results demonstrate that the zonal jets are driven by “eddy forcing” due to continuously created baroclinic perturbations. The flow is baroclinic to a significant degree and the jets are “surface intensified.” The meridional wavelength of the jets varies linearly with the baroclinic radius of deformation and is also in a good agreement with a modified Rhines scale. This suggests a linear dependence of the perturbation velocity in the Equilibrated baroclinically unstable flow on the β-parameter.
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zonal jets in equilibrating baroclinic instability on the polar beta plane experiments with altimetry
arXiv: Atmospheric and Oceanic Physics, 2015Co-Authors: Anna Magdalena Matulka, Y D AfanasyevAbstract:Results from the laboratory experiments on the evolution of baroclinically unstable flows generated in a rotating tank with topographic beta-effect are presented. We study zonal jets of alternating direction which occur in these flows. The primary system we model includes lighter fluid in the South and heavier fluid in the North with resulting slow meridional circulation and fast mean zonal motion. In a two-layer system the velocity shear between the layers results in baroclinic instability which Equilibrates with time and, due to interaction with beta-effect generates zonal jets. This system is archetypal for various geophysical systems including the general circulation and jet streams in the Earths atmosphere, the Antarctic Circumpolar Current or the areas in the vicinity of western boundary currents where baroclinic instability and multiple zonal jets are observed. The gradient of the surface elevation and the thickness of the upper layer are measured in the experiments using the Altimetric Imaging Velocimetry and the Optical Thickness Velocimetry techniques respectively. Barotropic and baroclinic velocity fields are then derived from the measured quantities. The results demonstrate that the zonal jets are driven by eddy forcing due to continuously created baroclinic perturbations. The flow is baroclinic to a significant degree and the jets are surface intensified. The meridional wavelength of the jets varies linearly with the baroclinic radius of deformation and is also in a good agreement with a modified Rhines scale. This suggests a linear dependence of the perturbation velocity in the Equilibrated baroclinically unstable flow on the beta-parameter.
Jerome Rech - One of the best experts on this subject based on the ideXlab platform.
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transport properties of partially Equilibrated quantum wires
Physical Review B, 2010Co-Authors: Tobias Micklitz, Jerome Rech, K A MatveevAbstract:We study the effect of thermal equilibration on the transport properties of a weakly interacting one-dimensional electron system. Although equilibration is severely suppressed due to phase-space restrictions and conservation laws, it can lead to intriguing signatures in partially Equilibrated quantum wires. We consider an ideal homogeneous quantum wire. At finite temperature we find a correction to the quantized conductance, which for a short wire scales with its length, but saturates in the limit of an infinitely long wire. We also discuss thermoelectric properties of long quantum wires. We show that the uniform quantum wire is a perfect thermoelectric refrigerator, approaching Carnot efficiency with increasing wire length.
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Conductance of fully Equilibrated quantum wires
Physical Review Letters, 2009Co-Authors: Jerome Rech, Tobias Micklitz, K A MatveevAbstract:We study the conductance of a quantum wire in the presence of weak electron-electron scattering. In a sufficiently long wire the scattering leads to full equilibration of the electron distribution function in the frame moving with the electric current. At non-zero temperature this equilibrium distribution differs from the one supplied by the leads. As a result the contact resistance increases, and the quantized conductance of the wire acquires a quadratic in temperature correction. The magnitude of the correction is found by analysis of the conservation laws of the system and does not depend on the details of the interaction mechanism responsible for equilibration.
Laurent Gallimard - One of the best experts on this subject based on the ideXlab platform.
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a constitutive relation error estimator based on traction free recovery of the Equilibrated stress
International Journal for Numerical Methods in Engineering, 2009Co-Authors: Laurent GallimardAbstract:A new methodology for recovering Equilibrated stress fields is presented, which is based on traction-free subdomains' computations. It allows a rather simple implementation in a standard finite element code compared with the standard technique for recovering Equilibrated tractions. These Equilibrated stresses are used to compute a constitutive relation error estimator for a finite element model in 2D linear elasticity. A lower bound and an upper bound for the discretization error are derived from the error in the constitutive relation. These bounds in the discretization error are used to build lower and upper bounds for local quantities of interest. Copyright © 2008 John Wiley & Sons, Ltd.
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A constitutive relation error estimator based on traction‐free recovery of the Equilibrated stress
International Journal for Numerical Methods in Engineering, 2008Co-Authors: Laurent GallimardAbstract:A new methodology for recovering Equilibrated stress fields is presented, which is based on traction-free subdomains' computations. It allows a rather simple implementation in a standard finite element code compared with the standard technique for recovering Equilibrated tractions. These Equilibrated stresses are used to compute a constitutive relation error estimator for a finite element model in 2D linear elasticity. A lower bound and an upper bound for the discretization error are derived from the error in the constitutive relation. These bounds in the discretization error are used to build lower and upper bounds for local quantities of interest. Copyright © 2008 John Wiley & Sons, Ltd.
Anna Magdalena Matulka - One of the best experts on this subject based on the ideXlab platform.
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zonal jets in equilibrating baroclinic instability on the polar beta plane experiments with altimetry
Journal of Geophysical Research, 2015Co-Authors: Anna Magdalena Matulka, Y D AfanasyevAbstract:Results from the laboratory experiments on the evolution of baroclinically unstable flows generated in a rotating tank with topographic β-effect are presented. We study zonal jets of alternating direction which occur in these flows. The primary system we model includes lighter fluid in the South and heavier fluid in the North with resulting slow meridional circulation and fast mean zonal motion. In a two-layer system, the velocity shear between the layers results in baroclinic instability which Equilibrates with time and, due to interaction with β-effect generates zonal jets. This system is archetypal for various geophysical systems including the general circulation and jet streams in the Earth's atmosphere, the Antarctic Circumpolar Current, or the areas in the vicinity of western boundary currents where baroclinic instability and multiple zonal jets are observed. The gradient of the surface elevation and the thickness of the upper layer are measured in the experiments using the Altimetric Imaging Velocimetry and the Optical Thickness Velocimetry techniques, respectively. Barotropic and baroclinic velocity fields are then derived from the measured quantities. The results demonstrate that the zonal jets are driven by “eddy forcing” due to continuously created baroclinic perturbations. The flow is baroclinic to a significant degree and the jets are “surface intensified.” The meridional wavelength of the jets varies linearly with the baroclinic radius of deformation and is also in a good agreement with a modified Rhines scale. This suggests a linear dependence of the perturbation velocity in the Equilibrated baroclinically unstable flow on the β-parameter.
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zonal jets in equilibrating baroclinic instability on the polar beta plane experiments with altimetry
arXiv: Atmospheric and Oceanic Physics, 2015Co-Authors: Anna Magdalena Matulka, Y D AfanasyevAbstract:Results from the laboratory experiments on the evolution of baroclinically unstable flows generated in a rotating tank with topographic beta-effect are presented. We study zonal jets of alternating direction which occur in these flows. The primary system we model includes lighter fluid in the South and heavier fluid in the North with resulting slow meridional circulation and fast mean zonal motion. In a two-layer system the velocity shear between the layers results in baroclinic instability which Equilibrates with time and, due to interaction with beta-effect generates zonal jets. This system is archetypal for various geophysical systems including the general circulation and jet streams in the Earths atmosphere, the Antarctic Circumpolar Current or the areas in the vicinity of western boundary currents where baroclinic instability and multiple zonal jets are observed. The gradient of the surface elevation and the thickness of the upper layer are measured in the experiments using the Altimetric Imaging Velocimetry and the Optical Thickness Velocimetry techniques respectively. Barotropic and baroclinic velocity fields are then derived from the measured quantities. The results demonstrate that the zonal jets are driven by eddy forcing due to continuously created baroclinic perturbations. The flow is baroclinic to a significant degree and the jets are surface intensified. The meridional wavelength of the jets varies linearly with the baroclinic radius of deformation and is also in a good agreement with a modified Rhines scale. This suggests a linear dependence of the perturbation velocity in the Equilibrated baroclinically unstable flow on the beta-parameter.