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Related papers: Apparent extracellular current density and extrace…

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The electrical properties of extracellular space around neurons are important to understand the genesis of extracellular potentials, as well as for localizing neuronal activity from extracellular recordings. However, the exact nature of…

In this paper, we have developed a theory describing surface exciton polariton (SEPs) that accounts for the spatial dispersion of the dielectric constant connected with exciton momentum. Due to strong coupling between light and bulk…

Mesoscale and Nanoscale Physics · Physics 2024-11-13 Jason Hao , Jeffrey Owrutsky , Daniel Ratchford , Blake Simpkins , Alexander L. Efros

We discuss the foundations and extend the range of applicability of the widely used Kubo-Greenwood formula (KGF) for the electronic conductivity. The conductivity is derived from the current density, and only the probability amplitude…

Statistical Mechanics · Physics 2009-04-02 Ming-Liang Zhang , D. A. Drabold

We present a collection of biophysics examination problems that focus on electrodiffusion, the superposition principle, and currents in RC circuits, leading towards an understanding of the Hodgkin-Huxley model of action potentials. These…

Physics Education · Physics 2022-08-10 Vadim Shlyonsky , Bertrand de Prelle , Florian Bodranghien , Don Patrick Bischop , David Gall

The current flux density is a vector field that can be used to describe theoretically how electrons flow in a system out-of-equilibrium. In this work, we unequivocally demonstrate that the signal obtained from time-resolved X-ray scattering…

Atomic Physics · Physics 2020-02-04 Gunter Hermann , Vincent Pohl , Gopal Dixit , Jean Christophe Tremblay

Numerous measurements in the brain of the impedance between two extracellular electrodes have shown that it is approximately resistive in the range of biological interest, $<10\,$kHz, and has a value close to that expected from the…

Neurons and Cognition · Quantitative Biology 2017-11-22 Boris Barbour

It is well understood that various alternatives are available within EM theory for the definitions of energy density, momentum transfer, EM stress-energy tensor, and so forth. Although the various options are all compatible with the basic…

General Physics · Physics 2010-09-28 H. E. Puthoff

Exciton superfluid is a macroscopic quantum phenomenon in which large quantities of excitons undergo the Bose-Einstein condensation. Recently, exciton superfluid has been widely studied in various bilayer systems. However, experimental…

Mesoscale and Nanoscale Physics · Physics 2015-07-22 Qing-Dong Jiang , Zhi-qiang Bao , Qing-Feng Sun , X. C. Xie

In a previous paper we suggested that a macroscopic force field applied across a two-dimensional electron gas channel could induce a microscopic charge density wave as soon as the proper compressibility becomes negative, which happens at…

Mesoscale and Nanoscale Physics · Physics 2020-11-24 Erica Hroblak , Mohammad Zarenia , Giovanni Vignale

Accurate simulations of electric fields (E-fields) in neural stimulation depend on tissue conductivity representations that link underlying microscopic tissue structure with macroscopic assumptions. Mesoscale conductivity variations can…

The Maxwell equations for an homogeneous medium in which electric currents are composed of Ohmic, diffusive and impressed currents are written in the static approximation in which displacements currents are neglected. Closed exact…

Biological Physics · Physics 2016-10-26 Alejandro Cabo , Jorge J. Riera , Pedro A. Valdes Hernandez

In the framework of quantum electrodynamics (QED) in external potentials, we introduce a method to compute the time-dependence of the expectation value of the current density for time-dependent homogeneous external electric fields. We apply…

High Energy Physics - Theory · Physics 2015-10-29 Jochen Zahn

We propose a general physics-based approach for an accurate analytical calculation of the channel charge density in field-effect transistors as functions of the external gate biases. This approach is based on a consistent consideration of…

Mesoscale and Nanoscale Physics · Physics 2022-01-03 G. I. Zebrev , D. S. Malich

Accurate electromagnetic modeling of the head of a subject is of main interest in the fields of source reconstruction and brain stimulation. Those processes rely heavily on the quality of the model and, even though the geometry of the…

Medical Physics · Physics 2022-02-15 Martin Grignard , Christophe Geuzaine , Christophe Phillips

Power laws, that is, power spectral densities (PSDs) exhibiting 1/f^alpha behavior for large frequencies f, have commonly been observed in neural recordings. Power laws in noise spectra have not only been observed in microscopic recordings…

Biological Physics · Physics 2015-06-15 Klas H. Pettersen , Henrik Lindén , Tom Tetzlaff , Gaute T. Einevoll

We present predictions on the angular power spectrum of CMB fluctuations due to extragalactic point sources (EPS) by using a method for simulating realistic 2D distributions of clustered EPS. Both radio and far--IR selected source…

Astrophysics · Physics 2009-11-10 J. González-Nuevo , L. Toffolatti , F. Argüeso

Quantum polarization effects associated with the conformal anomaly in a static magnetic field background may generate a transverse electric current in the vacuum. The current may be produced either in an unbounded curved spacetime or in a…

High Energy Physics - Theory · Physics 2019-01-09 M. N. Chernodub , V. A. Goy , A. V. Molochkov

We obtain the dipolar anisotropies in the arrival directions of ultra-high energy cosmic rays diffusing from nearby extragalactic sources. We discuss both the energy regime of spatial diffusion and the quasi-rectilinear one leading to just…

High Energy Astrophysical Phenomena · Physics 2014-06-11 Diego Harari , Silvia Mollerach , Esteban Roulet

Current-free double layers of the type reported in plasmas in the presence of an expanding magnetic field [C. Charles and R. W. Boswell, Appl. Phys. Lett. 82, 1356 (2003)] are modeled theoretically and with particle-in-cell/Monte Carlo…

Plasma Physics · Physics 2015-06-12 S. D. Baalrud , T. Lafleur , R. W. Boswell , C. Charles

The effective electromagnetic current density for a two-nucleon system that is described by the Blankenbecler-Sugar equation is derived. In addition to the single nucleon currents there are exchange currents of two different origins. The…

Nuclear Theory · Physics 2009-10-22 F. Coester , D. O. Riska