The Lorentz force and superconductivity
TL;DR: In this article, the authors point out that within the conventional understanding of superconductivity electrons appear to change their velocity in the absence of Lorentz forces, which indicates a fundamental problem with the conventional theory.
Abstract: To change the velocity of an electron requires that a Lorentz force acts on it, through an electric or a magnetic field. We point out that within the conventional understanding of superconductivity electrons appear to change their velocity in the absence of Lorentz forces. This indicates a fundamental problem with the conventional theory of superconductivity. A hypothesis is proposed to resolve this difficulty. This hypothesis is consistent with the theory of hole superconductivity.
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TL;DR: In this paper, an alternative to conventional BCS theory is proposed to apply to all superconductors, 'conventional' as well as 'unconventional', that offers an explanation for the Meissner effect as well well as for other puzzles and provides clear guidelines in the search for new high temperature supercondors.
Abstract: The time-tested Bardeen–Cooper–Schrieffer (BCS) theory of superconductivity is generally accepted to be the correct theory of conventional superconductivity by physicists and, by extension, by the world at large. There are, however, an increasing number of 'red flags' that strongly suggest the possibility that BCS theory may be fundamentally flawed. An ever-growing number of superconductors are being classified as 'unconventional', not described by the conventional BCS theory and each requiring a different physical mechanism. In addition, I argue that BCS theory is unable to explain the Meissner effect, the most fundamental property of superconductors. There are several other phenomena in superconductors for which BCS theory provides no explanation. Furthermore, BCS theory has proven unable to predict any new superconducting compounds. This paper suggests the possibility that BCS theory itself as the theory of 'conventional' superconductivity may require a fundamental overhaul. I outline an alternative to conventional BCS theory proposed to apply to all superconductors, 'conventional' as well as 'unconventional', that offers an explanation for the Meissner effect as well as for other puzzles and provides clear guidelines in the search for new high temperature superconductors.
88 citations
Cites background from "The Lorentz force and superconducti..."
...[122] Hirsch JE (2003) The Lorentz force and superconduc-...
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...The theory also offers compelling explanations for the Tao effect[142], the puzzles of rotating superconductors[122, 123], Chapnik’s rule[143], and the variation of Tc along the elements in the transition metal series[144, 145]....
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...(1), and, negative charge needs to move inward to satisfy mechanical equilibrium[122, 123]....
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...The only forces in nature that are relevant in this context (of course gravitational and nuclear forces are irrelevant) are the Lorentz electromagnetic force[122] and ‘quantum pressure’, the tendency of quantum particles to lower their kinetic energy by radially expanding their wavefunction[128]....
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...The theory offers a compelling explanation for the Meissner effect[122, 126, 129]: in essence, the azimuthal force propelling the electrons in the Meissner current is the magnetic Lorentz force acting on electrons moving radially outward....
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TL;DR: In this paper, a single mechanism of superconductivity for all materials, that explains the Meissner effect and differs from the conventional mechanism in several fundamental aspects: it says that superconduction is driven by lowering of kinetic rather than potential energy of the charge carriers, it requires conduction by holes rather than electrons in the normal state, and it predicts a non-homogeneous rigid charge distribution and an electric field in the interior of the superconductors, and a spin current near the surface.
Abstract: It is generally believed that superconducting materials are divided into two classes: ?conventional? and ?unconventional?. Conventional superconductors (the elements and thousands of compounds including MgB2) are described by conventional London?BCS?Eliashberg electron?phonon theory. There is no general agreement as to what mechanism or mechanisms describe ?unconventional? superconductors such as the heavy fermions, organics, cuprate and pnictide families. However all superconductors, whether ?conventional? or ?unconventional?, exhibit the Meissner effect. I argue that there is a single mechanism of superconductivity for all materials, that explains the Meissner effect and differs from the conventional mechanism in several fundamental aspects: it says that superconductivity is driven by lowering of kinetic rather than potential energy of the charge carriers, it requires conduction by holes rather than electrons in the normal state, and it predicts a non-homogeneous rigid charge distribution and an electric field in the interior of superconductors, and a spin current near the surface. Furthermore I argue that neither the conventional mechanism nor any of the other proposed unconventional mechanisms can explain the Meissner effect. Superconductivity in materials is discussed in the light of these concepts, some experimental predictions, connections to Dirac's theory, and connections to the superfluidity of 4He.
57 citations
TL;DR: In a voltaic cell, positive (negative) ions flow from the low (high) potential electrode to the high (low), potential electrode, driven by an "electromotive force" which points in opposite direction and overcomes the electric force as discussed by the authors.
Abstract: In a voltaic cell, positive (negative) ions flow from the low (high) potential electrode to the high (low) potential electrode, driven by an ‘electromotive force’ which points in opposite direction and overcomes the electric force. Similarly in a superconductor charge flows in direction opposite to that dictated by the Faraday electric field as the magnetic field is expelled in the Meissner effect. The puzzle is the same in both cases: what drives electric charges against electromagnetic forces? I propose that the answer is the same in both cases: kinetic energy lowering, or ‘quantum pressure.’
42 citations
TL;DR: In this article, a fully consistent model to study electrodynamics for superconductors in the stationary and non-stationary regimes has been developed based on Proca equations and a massive photon.
37 citations
TL;DR: The theory of hole superconductivity was proposed in this article, which describes heavy dressed positive hole carriers in normal state that undress by pairing and become light undressed negative electron carriers in the superconducting state.
35 citations
References
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TL;DR: In this paper, the Suprastrom wird durch ein Magnetfeld aufrechterhalten, welches seinerseits von dem Strome selbst erzeugt sein kann.
129 citations
TL;DR: In this paper, a Stromhaut an der Oberflache, deren Dicke ungefahr 10−6 cm betragt, was nach verschiedenen methoden der Strom berechnet.
Abstract: In1. bis3. wird nach verschiedenen Methoden der Strom berechnet, der in einer supraleitenden Kugel entsteht, wenn man diese in Rotation versetzt. Bei Berucksichtigung der Massentragheit der Elektronen ergibt sich eine Stromhaut an der Oberflache, deren Dicke ungefahr 10−6 cm betragt. In4. wird darauf hingewiesen, das auch der Oberflachenstrom, mit dem man bei der ublichen Anwendung der Maxwellschen Theorie auf ruhende Supraleiter rechnet, bei strengerer Betrachtungsweise durch einen Volumenstrom von der gleichen Ausdehnung zu ersetzen ist.
111 citations
TL;DR: In this paper, it was shown that even when interelectronic interactions are taken into account, the state of lowest electronic free energy corresponds to a zero net current, which contradicts the hypothesis that superconductivity is caused by spontaneous currents.
Abstract: Attention is called to a theorem of Bloch, from which it is shown that even when interelectronic interactions are taken into account, the state of lowest electronic free energy corresponds to a zero net current. This result contradicts the hypothesis that superconductivity is caused by spontaneous currents.
92 citations