Many physicists limit oneself to an instrumentalist description of quantum phenomena and ignore the problems of
foundation and interpretation of quantum mechanics. This instrumentalist approach results to "specialization barbarism"
and mass delusion concerning the problem, how a quantum computer can be made. The idea of quantum computation
can be described within the limits of quantum formalism. But in order to understand how this idea can be put into
practice one should realize the question: "What could the quantum formalism describe?", in spite of the absence of an
universally recognized answer. Only a realization of this question and the undecided problem of quantum foundations
allows to see in which quantum systems the superposition and EPR correlation could be expected. Because of the
"specialization barbarism" many authors are sure that Bell proved full impossibility of any hidden-variables
interpretation. Therefore it is important to emphasize that in reality Bell has restricted to validity limits of the no-hidden-variables
proof and has shown that two-state quantum system can be described by hidden variables. The later means that
no experimental result obtained on two-state quantum system can prove the existence of superposition and violation of
the realism. One should not assume before unambiguous experimental evidence that any two-state quantum system is
quantum bit. No experimental evidence of superposition of macroscopically distinct quantum states and of a quantum bit
on base of superconductor structure was obtained for the present. Moreover same experimental results can not be
described in the limits of the quantum formalism.
The quantum oscillations V(Φ/Φ_{0}) of the dc voltage are induced on segments of asymmetric superconducting loops by an external ac current or noise. The dependencies of the amplitude of V(Φ/Φ_{0}) on amplitude of inducing ac current are measured at different temperatures below superconducting transition T_{c} on aluminum asymmetric loops and systems of the loops connected in series. The measured values of the maximum amplitude of the quantum oscillations V(Φ/Φ_{0}), the amplitude of the ac current inducing this maximum dc voltage and the critical amplitude of the ac current decrease with temperature increase to T_{c}. The extrapolation of these measured dependencies to the region near superconducting transition allows to make a calibration of asymmetric superconducting loops as quantum detector of noise. The calibration restores an amplitude profile of the noise pulses from a measured temperature dependence of an amplitude of the quantum oscillations V(Φ/Φ_{0}) induced by this noise. It is found that rectification efficiency, determined as relation of the maximum amplitude of the quantum oscillations V(Φ/Φ_{0}) to the ac current amplitude inducing it, decreases near superconducting transition T_{c}. High efficiency of rectification observed below T_{c} is consequence of irreversibility of the current-voltage curves. Increase of the rectification efficiency is achieved in multiple series connected loop structures.
The idea of the quantum computation is based on paradoxical principles of quantum physics superposition and entanglement of quantum states. This idea looks well-founded on the microscopic level in spite of the absence of an universally recognized interpretation of these paradoxical principles since they were corroborated over and over again by reliable experiments on the microscopic level. But the technology can not be able in the near future to work on the microscopic level. Therefore macroscopic quantum phenomenon-superconductivity is very attractive for the realization of the idea of quantum computer. It is shown in the present paper that a chain of superconducting loops can be only possible quantum register. The proposals by some authors to provide the EPR correlation with help of a classical interaction witness the misunderstanding of the entanglement essence. The problem of the possibility of superposition of macroscopically distinct states is considered.
The problem of possible violation of the second law of thermodynamics is discussed. It is noted that the task of the well known challenge to the second law called Maxwell's demon is put in order a chaotic perpetual motion and if any ordered Brownian motion exists then the second law can be broken without this hypothetical intelligent entity. The postulate of absolute randomness of any Brownian motion saved the second law in the beginning of the 20th century when it was realized as perpetual motion. This postulate can be proven in the limits of classical mechanics but is not correct according to quantum mechanics. Moreover some enough known quantum phenomena, such as the persistent current at non-zero resistance, are an experimental evidence of the non-chaotic Brownian motion with non-zero average velocity. An experimental observation of a dc quantum power soruce is interperted as evidence of violation of the second law.
A dc voltage changed periodically with magnetic field is observed on segments of asymmetric aluminum loop without any external dc current at temperatures corresponded to superconducting transition. According to this experimental result a segment of the loop is a dc power source. A possibility of a persistent voltage on segments of an inhomogeneous normal metal mesoscopic loop follows from this result.