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Title: On the reversibility of the Meissner effect and the angular momentum puzzle

Abstract

It is generally believed that the laws of thermodynamics govern superconductivity as an equilibrium state of matter, and hence that the normal-superconductor transition in a magnetic field is reversible under ideal conditions. Because eddy currents are generated during the transition as the magnetic flux changes, the transition has to proceed infinitely slowly to generate no entropy. Experiments showed that to a high degree of accuracy no entropy was generated in these transitions. However, in this paper we point out that for the length of times over which these experiments extended, a much higher degree of irreversibility due to decay of eddy currents should have been detected than was actually observed. We also point out that within the conventional theory of superconductivity no explanation exists for why no Joule heat is generated in the superconductor to normal transition when the supercurrent stops. In addition we point out that within the conventional theory of superconductivity no mechanism exists for the transfer of momentum between the supercurrent and the body as a whole, which is necessary to ensure that the transition in the presence of a magnetic field respects momentum conservation. We propose a solution to all these questions based on the alternativemore » theory of hole superconductivity. The theory proposes that in the normal-superconductor transition there is a flow and backflow of charge in direction perpendicular to the phase boundary when the phase boundary moves. We show that this flow and backflow explains the absence of Joule heat generated by Faraday eddy currents, the absence of Joule heat generated in the process of the supercurrent stopping, and the reversible transfer of momentum between the supercurrent and the body, provided the current carriers in the normal state are holes. - Highlights: • The normal-superconductor phase transition is reversible. • Within the conventional theory, Foucault currents give rise to irreversibility. • To suppress Foucault currents, charge has to flow in direction perpendicular to the phase boundary. • The charge carriers have to be holes. • This solves also the angular momentum puzzle associated with the Meissner effect.« less

Authors:
Publication Date:
OSTI Identifier:
22617399
Resource Type:
Journal Article
Resource Relation:
Journal Name: Annals of Physics; Journal Volume: 373; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANGULAR MOMENTUM; EDDY CURRENTS; ENTROPY; MAGNETIC FIELDS; MAGNETIC FLUX; MEISSNER-OCHSENFELD EFFECT; SUPERCONDUCTIVITY; SUPERCONDUCTORS; THERMODYNAMICS

Citation Formats

Hirsch, J.E., E-mail: jhirsch@ucsd.edu. On the reversibility of the Meissner effect and the angular momentum puzzle. United States: N. p., 2016. Web. doi:10.1016/J.AOP.2016.07.002.
Hirsch, J.E., E-mail: jhirsch@ucsd.edu. On the reversibility of the Meissner effect and the angular momentum puzzle. United States. doi:10.1016/J.AOP.2016.07.002.
Hirsch, J.E., E-mail: jhirsch@ucsd.edu. Sat . "On the reversibility of the Meissner effect and the angular momentum puzzle". United States. doi:10.1016/J.AOP.2016.07.002.
@article{osti_22617399,
title = {On the reversibility of the Meissner effect and the angular momentum puzzle},
author = {Hirsch, J.E., E-mail: jhirsch@ucsd.edu},
abstractNote = {It is generally believed that the laws of thermodynamics govern superconductivity as an equilibrium state of matter, and hence that the normal-superconductor transition in a magnetic field is reversible under ideal conditions. Because eddy currents are generated during the transition as the magnetic flux changes, the transition has to proceed infinitely slowly to generate no entropy. Experiments showed that to a high degree of accuracy no entropy was generated in these transitions. However, in this paper we point out that for the length of times over which these experiments extended, a much higher degree of irreversibility due to decay of eddy currents should have been detected than was actually observed. We also point out that within the conventional theory of superconductivity no explanation exists for why no Joule heat is generated in the superconductor to normal transition when the supercurrent stops. In addition we point out that within the conventional theory of superconductivity no mechanism exists for the transfer of momentum between the supercurrent and the body as a whole, which is necessary to ensure that the transition in the presence of a magnetic field respects momentum conservation. We propose a solution to all these questions based on the alternative theory of hole superconductivity. The theory proposes that in the normal-superconductor transition there is a flow and backflow of charge in direction perpendicular to the phase boundary when the phase boundary moves. We show that this flow and backflow explains the absence of Joule heat generated by Faraday eddy currents, the absence of Joule heat generated in the process of the supercurrent stopping, and the reversible transfer of momentum between the supercurrent and the body, provided the current carriers in the normal state are holes. - Highlights: • The normal-superconductor phase transition is reversible. • Within the conventional theory, Foucault currents give rise to irreversibility. • To suppress Foucault currents, charge has to flow in direction perpendicular to the phase boundary. • The charge carriers have to be holes. • This solves also the angular momentum puzzle associated with the Meissner effect.},
doi = {10.1016/J.AOP.2016.07.002},
journal = {Annals of Physics},
number = ,
volume = 373,
place = {United States},
year = {Sat Oct 15 00:00:00 EDT 2016},
month = {Sat Oct 15 00:00:00 EDT 2016}
}