Could ordinary quantum mechanics be just fine for all practical purposes?

Nikulov, A. V.

doi:10.1007/s40509-015-0057-3

Cited by 12 publications

(11 citation statements)

References 41 publications

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“…In this simplified model only the kinetic energy of the superconducting condensate is taken into account and the magnetic field distortion by the Meissner effect is neglected. A more rigorous theoretical model might need to include the magnetic moment of the supercurrent in the loop and its interaction with the applied field [36,37]. In the present model, the phase gradients in the electrodes are assumed to be created by the Meissner current in the electrodes and negligibly affected by the applied supercurrents through the nanowires because the wires are very weak superconductors compared to the electrodes [17].…”

Section: Current-phase Relationshipmentioning

confidence: 99%

Asymmetric nanowire SQUID: Linear current-phase relation, stochastic switching, and symmetries

Murphy

Bezryadin

2017

Phys. Rev. B

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We study nanodevices based on ultrathin superconducting nanowires connected in parallel to form nanowire SQUIDs. The function of the critical current versus magnetic field, IC (B), is multivalued, asymmetric and its maxima and minima are shifted from the usual integer and half integer flux quantum points. The nanowire interference device is qualitatively distinct from conventional SQUIDs because nanowires do not obey the same current-phase relationship (CPR) as Josephson junctions. We demonstrate that the results can be explained assuming that (i) the CPR is linear and (ii) that each wire is characterized by a sample-specific critical phase, which is usually much larger than π/2. Our proposed model offers accurate fits to IC (B). It explains the single-valuedness regions where only one vorticity (i.e., the order parameter winding number) is stable as well as regions where multiple vorticity values are allowed for the SQUIDs. We also observe and explain regions in which the standard deviation of the switching current is independent of the magnetic field. We develop a technique that allows a reliable detection of hidden phase-slips. Using this technique we find that our model correctly predicts the boundaries of vorticity regions, even at low currents where IC (B) is not directly measurable.

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Section: Current-phase Relationshipmentioning

confidence: 99%

Asymmetric nanowire SQUID: Linear current-phase relation, stochastic switching, and symmetries

Murphy

Bezryadin

2017

Phys. Rev. B

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“…L /s)µ 0 2πr and the magnetic flux induced by the persistent current is small ∆Φ I = L f I p ≪ Φ = BS [24].…”

Section: The Conventional Theories Do Not Describe Dynamic Processes ...mentioning

confidence: 99%

“…The measurements [5][6][7][8][9][42][43][44][45] of the dc voltage V dc ∝ I p indicate the observation of a dc power source V dc I p or V 2 dc /R s since the persistent current flows against the dc voltage in one of the ring halves [24] like in the case of the conventional circular electric current (14). Analogy with the electric transformer may be useful here [5].…”

Section: Dynamic Processes In Asymmetric Superconducting Ringsmentioning

confidence: 99%

Dynamic processes in superconductors and the laws of thermodynamics

Nikulov

2021

Preprint

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The transition from the superconducting to the normal state in a magnetic field was considered as a irreversible thermodynamic process before 1933 because of Joule heating. But all physicists became to consider this transition as reversible after 1933 because of the obvious contradiction of the Meissner effect with the second law of thermodynamics if this transition is considered as a irreversible process. This radical change of the opinion contradicted logic since the dissipation of the kinetic energy of the surface screening current into Joule heat in the normal state cannot depend on how this current appeared in the superconducting state. The inconsistency of the conventional theory of superconductivity, created in the framework of the equilibrium thermodynamics, with Joule heating, on which Jorge Hirsch draws reader's attention, is a consequence of this history. In order to avoid contradiction with the second law of thermodynamics, physicists postulated in the thirties of the last century that the surface screening current is damped without the generation of Joule heat. This postulate contradicts not only logic and the conventional theory of superconductivity but also experimental results.

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“…De Waele et al [ 48 ] did not take into account that the DC voltage

is observed in a magnetic field constant in time, i.e., without the Faraday electromotive force

. Therefore, the persistent current flows against the total electric field

in one of the ring halves [ 55 ], in contrast to the conventional circular current I (12), which flows against the potential electric field

, but not against the total electric field

. This paradox can be explain only if we take into account that the quantum force (11) replaces the Faraday electromotive force and counteract to the dissipation force [ 56 ] when rings are switched between superconducting and normal states.…”

Section: The Assumption Of Molecular Disorder Belong To Our Empirical Rather Than a Priori Knowledgementioning

confidence: 99%

The Law of Entropy Increase and the Meissner Effect

Nikulov

2022

Entropy

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The law of entropy increase postulates the existence of irreversible processes in physics: the total entropy of an isolated system can increase, but cannot decrease. The annihilation of an electric current in normal metal with the generation of Joule heat because of a non-zero resistance is a well-known example of an irreversible process. The persistent current, an undamped electric current observed in a superconductor, annihilates after the transition into the normal state. Therefore, this transition was considered as an irreversible thermodynamic process before 1933. However, if this transition is irreversible, then the Meissner effect discovered in 1933 is experimental evidence of a process reverse to the irreversible process. Belief in the law of entropy increase forced physicists to change their understanding of the superconducting transition, which is considered a phase transition after 1933. This change has resulted to the internal inconsistency of the conventional theory of superconductivity, which is created within the framework of reversible thermodynamics, but predicts Joule heating. The persistent current annihilates after the transition into the normal state with the generation of Joule heat and reappears during the return to the superconducting state according to this theory and contrary to the law of entropy increase. The success of the conventional theory of superconductivity forces us to consider the validity of belief in the law of entropy increase.

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Could ordinary quantum mechanics be just fine for all practical purposes?

Cited by 12 publications

References 41 publications

Asymmetric nanowire SQUID: Linear current-phase relation, stochastic switching, and symmetries

Asymmetric nanowire SQUID: Linear current-phase relation, stochastic switching, and symmetries

Dynamic processes in superconductors and the laws of thermodynamics

The Law of Entropy Increase and the Meissner Effect

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