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A. V. Nikulov

Publications and source records attributed to A. V. Nikulov.

At least 19 recordsLinked to original sources

Belief in thermodynamics has provoked false thermodynamics of superconductors

Belief in thermodynamics has forced superconductivity experts to forget basics of thermodynamics due to a contradiction of superconductivity phenomena to laws of thermodynamics. Because of this belief no one drew reader's attention during many years that the conventional theory of superconductivity contradicts to the second law of thermodynamics. The common belief that the superconducting transition occurs when the free energy of the superconducting state becomes less than of the normal state has provoked a false claim that a power source of a solenoid creates the energy of magnetization rather than of magnetic field. The authors of only a few books on superconductivity, mostly future Nobel prize winners, did not follow this false claim. No one for many years has noticed that the equality of free energies at the superconducting transition in the critical magnetic field cannot be obtained without contradicting the second law of thermodynamics. The Meissner effect violates the second law of thermodynamics because of the negative surplus work performed in the closed Gorter cycle. The desire to avoid contradiction of superconductivity phenomena with the second law of thermodynamics provoked the false thermodynamics of superconductors, contradicting the law of conservation of energy.

physics.gen-ph

The Meissner effect does not require radial charge flow

The Meissner effect is the expulsion of magnetic flux from the interior of a bulk superconductor in the presence of the constant critical magnetic field by the persistent current circulating near the surface of the superconductor. The conventional theory of superconductivity explains the appearance of the persistent current in the Meissner effect and other macroscopic quantum phenomena observed in superconductors as a consequence of the quantization of angular momentum of Cooper pairs. According to the alternative theory of hole superconductivity the persistent current appears due to the Lorentz force acting on a radial charge flow rather than due to quantization. Therefore, the author of this theory, Jorge Hirsch, argues in his numerous publications that a radial charge flow is required to explain the Meissner effect. This article draws attention to the fact that the appearance of the persistent current because of quantization is not only the statement of the conventional theory of superconductivity, but first of all the experimental fact that cannot be explained using the Lorentz force. Therefore, the explanation of the Meissner effect does not require radial charge flow.

cond-mat.supr-con

Reply to Comment on 'The Law of Entropy Increase and the Meissner Effect'

Jorge Hirsch, in his Comment on my article published in Entropy, agrees that the conventional BCS theory of superconductivity contradicts the second law of thermodynamics. He tries to prove that this theory cannot be valid because of this contradiction, since the Meissner effect is consistent with the second law of thermodynamics, according to his alternative theory of superconductivity, which can explain how the persistent currents can be annihilated before the resistance appearance. First of all I draw attention on experimental facts according to which the persistent currents observed in rings can be not annihilated not only before but even after the resistance appearance, in accordance with the conventional theory of superconductivity and contrary to the second law of thermodynamics. Hirsch's proof of the consistency of the Meissner effect with the second law of thermodynamics is based on mistakes provoked by ignoring the contradictions between books on superconductivity and the false analogy of the Gorter cycle with the Carnot cycle. In fact, Hirsch did not refute, but confirmed the conclusion made in my article about the contradiction of the Meissner effect to the second law of thermodynamics.

cond-mat.supr-con

A problem with the conservation law observed in macroscopic quantum phenomena is a consequence of violation of the correspondence principle

This article draws attention that the puzzle of the change of the angular momentum without any force is a consequence of the contradiction of macroscopic quantum phenomena with the correspondence principle, which reveals a fundamental difference between microscopic quantum phenomena, described by the Schrodinger wave mechanics, and macroscopic quantum phenomena, described by the theory of superconductivity and the theory of superfluidity. To explain why macroscopic quantum phenomena are observed despite the correspondence principle, Lev Landau postulated in 1941 that microscopic particles in superfluid helium and superconductor cannot move separately. The angular momentum can change without any force only due to quantization in both microscopic and macroscopic quantum phenomena. The Heisenberg uncertainty principle eliminates the contradiction with the conservation law in the first case, since according to the correspondence principle, the change in angular momentum cannot exceed the Planck constant. But this principle cannot eliminate the contradiction with the conservation law the macroscopic change of angular momentum due to quantization observed in superconductors contrary to the correspondence principle. Quantization can change not only the angular momentum, but also the kinetic energy of a superconducting condensate on a macroscopic amount. For this reason, the Meissner effect and other macroscopic quantum phenomena contradict the second law of thermodynamics. The reluctance of physicists to admit the violation of the second law of thermodynamics provoked a false understanding of the phenomenon of superconductivity and obvious contradictions in books on superconductivity.

cond-mat.supr-con

Comment on "Case of thermodynamic failure in the Ginzburg-Landau approach to fluctuation superconductivity"

Jorge Berger shows theoretically in the paper Phys. Rev. B 109, 024501 (2024) that according to the Ginzburg-Landau theory the persistent current can create the persistent voltage, i.e. a dc voltage at thermodynamic equilibrium, on segments of nonuniform superconducting loop. A similar result was published early and was collaborated experimentally. The persistent power estimated by Berger is compared with the experimentally observed power. The attention of experimenters is drawn to the possibility to observe the persistent voltage thanks to its increase with the number of identical rings connected in series.

physics.gen-ph

The law of entropy increase and the Meissner effect

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 well-known example of 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 irreversible thermodynamic process before 1933. But 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 to consider the validity of belief in the law of entropy increase.

physics.gen-ph

Comment on "Reversible superconducting-normal phase transition in a magnetic field and the existence of topologically protected loop currents that appear and disappear without Joule heating" by Hiroyasu Koizumi

This comment is written on the article by Hiroyasu Koizumi, in which an alternative theory of superconductivity is proposed. No Joule heating is predicted in this theory unlike the conventional BCS-London theory of superconductivity. The theory is based on the author's opinion that the kinetic energy for the supercurrent is converted into the energy of the magnetic field during the transition of a bulk superconductor into the normal state in the presence of a magnetic field. The Comment indicates that this opinion cannot be correct, since the kinetic energy is much less than the energy of the magnetic field and both of these energies decrease during the transition to the normal state, according to the generally accepted point of view. It is briefly explained how a reversible thermodynamic process differs from an irreversible process.

cond-mat.supr-con

Dynamic processes in superconductors and the laws of thermodynamics

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.

cond-mat.supr-con

Experimental investigations of the problem of the quantum jump with the help of superconductor nanostructures

The quantum theory, that we now know, arose in the process of sharp disputes between its creators. One of the results of these disputes was the emergence in recent years of fundamentally new areas of investigation and technology - quantum information and quantum computing. One of the subjects of controversy between the creators of quantum theory was the quantum jump. We draw the attention to the possibility of experimental investigation of this problem with the help of quantum superconductor nanostructures. The first results of experiments are presented, the paradoxicality of which indicates the relevance of the problem.

cond-mat.supr-con

Observation of flux qubit states with the help of a superconducting differential double contour interferometer

The quantum states of flux qubit is suggested to observe with the help of a new device, the superconducting differential double contour interferometer (DDCI). The flux qubit and the superconducting quantum interference device (DC-SQUID) are connected in the DDCI through the phase of the wave function rather than through magnetic flux. The critical current of DC-SQUID should change to the maximum value at the change of the flux qubit state thanks to this phase coupling. A large jump in the critical current and voltage enables to observe continuously the change in time the state of the flux qubit. This observation can have fundamental importance for the investigation of the superposition of macroscopic quantum states.

cond-mat.supr-con

Observation of dc power on system of identical asymmetric superconducting rings

The observations the dc voltage on asymmetric superconducting ring testify that one of the ring segments is a dc power source. The persistent current flows against the total electric field in this segment. This paradoxical phenomenon is observed when the ring or its segments are switched between superconducting and normal state by non-equilibrium noises. We demonstrate that the dc voltage and the power increase with the number of the identical rings connected in series. Large voltage and power sufficient for practical application can be obtained in a system with a sufficiently large number of the rings. We point to the possibility of using such a system for the observation of the dc voltage above superconducting transition and in the asymmetric rings made of normal metal.

cond-mat.supr-con

A development of superconducting differential double contour interferometer

We study operation of a new device, the superconducting differential double contour interferometer (DDCI), in application for the ultra sensitive detection of magnetic flux and for digital read out of the state of the superconducting flux qubit. DDCI consists of two superconducting contours weakly coupled by Josephson Junctions. In such a device a change of the critical current and the voltage happens in a step-like manner when the angular momentum quantum number changes in one of the two contours. The DDCI may outperform traditional Superconducting Quantum Interference Devices when the change of the quantum number occurs in a narrow magnetic field region near the half of the flux quantum due to thermal fluctuations, quantum fluctuations, or the switching a loop segment in the normal state for a while by short pulse of an external current.

cond-mat.supr-con

Quantum periodicity in the critical current of superconducting rings with asymmetric link-up of current leads

We use superconducting rings with asymmetric link-up of current leads for experimental investigation of winding number change at magnetic field corresponding to the half of the flux quantum inside the ring. According to the conventional theory, the critical current of such rings should change by jump due to this change. Experimental data obtained at measurements of aluminum rings agree with theoretical prediction in magnetic flux region close to integer numbers of the flux quantum and disagree in the region close to the half of the one, where a smooth change is observed instead of the jump. First measurements of tantalum ring give a hope for the jump. Investigation of this problem may have both fundamental and practical importance.

physics.gen-ph

Multiple superconducting ring ratchets for ultrasensitive detection of non-equilibrium noise

Magnetic quantum periodicity in the dc voltage is observed when asymmetric rings are switched between superconducting and normal state by a noise or ac current. This quantum effect is used for detection of a non-equilibrium noise with the help of a system of 667 asymmetric aluminum rings of $1 \ μm$ in diameter connected in series. Any noise down to the equilibrium one can be detected with the help of such system with enough great number of asymmetric rings.

cond-mat.supr-con

Energy of magnetic moment of superconducting current in magnetic field

The energy of magnetic moment of the persistent current circulating in superconducting loop in an externally produced magnetic field is not taken into account in the theory of quantization effects because of identification of the Hamiltonian with the energy. This identification misleads if, in accordance with the conservation law, the energy of a state is the energy expended for its creation. The energy of magnetic moment is deduced from a creation history of the current state in magnetic field both in the classical and quantum case. But taking this energy into account demolishes the agreement between theory and experiment. Impartial consideration of this problem discovers the contradiction both in theory and experiment.

cond-mat.supr-con

Superconducting quantum interference device without Josephson junctions

A new type of a superconducting quantum interference device (SQUID) based on a single superconducting loop without Josephson junctions and with asymmetric link-up of current leads is proposed. This SQUID offers advantages in simplicity of fabrication and higher sensitivity of magnetic flux. Magnetic field dependence of the critical current in aluminium rings with asymmetric link-up of current leads has been measured in order to confirm the possibility of making this type of SQUID.

cond-mat.supr-con

Comment on "Vortices induced in a superconducting loop by asymmetric kinetic inductance and their detection in transport measurements"

The paper by G. R. Berdiyorov, M. V. Milosevic, and F. M. Peeters [Phys. Rev. B 81, 144511 (2010)] studies theoretically the dynamic properties of a superconducting loop. The authors claim that their consideration of asymmetric loop relates to our experimental results in this field. We point out that this claim is incorrect and explain shortly the true paradoxical essence of the results of our measurements of asymmetric superconducting loop.

cond-mat.supr-con