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The principle of quantum fluctuation compression with parametric control of the oscillatory system employed in ultra-high sensitivity measurements is discussed. An experiment is proposed in which a quantum compression mode is realized in a hysteresis-free regime with SQUID RF parametric pumping and a special microwave test signal.

The economists have so far paid little attention to the issues of the dollarization of the Russian economy and its financial system. This is inconsistent with the importance of the problem. As part of the solution of the problem of dedollarization the article proposes a proactive approach that involves, in addition to macroeconomic stabilization, changing prudential norms that regulate the banking sector, measures of institutional and fiscal nature which would increase the cost of foreign currency financial intermediation.

SQUID-magnetostrictor is the high sensitive system capable to measure deviations of mechanical tension. This measuring system may find application in different fields but it seems to be rather promising as a gravitational waves detector.

It is shown that a sequence of processes is possible in ferroelectrics, analogous to those which occur when a saturated paramagnetic material is cooled under adiabatic depolarization conditions, and it becomes a ferromagnetic material. The conditions required to construct a dielectric calorimeter with an extremely high sensitivity of 0.04 eV/Hz1/2 are considered.

We show that in some cases, in measurements at the level when quantum limits on accuracy begin to have an appreciable effect, we can use quantum entanglement of states in the studied system for extensive active suppression of background noise. We consider examples in which entanglement provides an “extra degree of freedom”, making it possible to select the desired events while rejecting the noise.

The existence of space inhomogeneous superconductor insulator state (SISIS) found out earlier in polycrystalline samples of high- TC system Ba0.6K0.4BiO3 (TC≈30 K) is confirmed on Ba0.6K0.4BiO3 single crystal. At T* (T*

The properties of the conversion of “cold” extra-light scalar or pseudo-scalar bosons weakly interacting with material media to photons with energies of 0.001–1.0 meV are analyzed. Various possible experimental schemes including closed resonant cells at low temperatures and highly sensitive receivers of radio-frequency photons are presented. The existence of such elementary particles is predicted in various expansion versions of the “standard model”. Their direct or indirect detection would make it possible to clarify the nature of the “dark matter” phenomenon.

Features of the propagation of a pulsed magnetic disturbance in a closed superconducting slit microwave transmission line are analyzed in the context of nonlocality of an action on a quantum object. It is suggested that, in contrast to previously conducted experiments with photons, such an approach enables us to specify the result of nonlocality of an action in a simpler situation with only a single component of the electromagnetic radiation.

The history of the question on the possibility of detecting gravitational waves, whose existence is predicted by the General Relativity Theory, is briefly presented. The schemes of cryofiber interferometer, which we propose to use as detector of gravitational waves with amplitude |δgij| = 10−20, are described. We also consider other versions of the use of cryofiber interferometer in both applied and fundamental context, including laboratory experiments in which according to the estimates dark energy density variations can be detected. We describe briefly the optical scheme of a compact interferometric detector of vibrations of a mirror fixed at the end of a massive gravitational antenna; the compactness admits construction of a cryogenic version with cooling of all the elements of such a recording system.

The characteristics of high performance signal detection over a wide frequency range (1 MHz ÷ 100 GHz) in the context of a non-standard application for tunnel diodes is discusses.

The periodical-in-voltage features of the negative differential conductance (NDC) region in the current-voltage characteristics of a high-quality GaAs/AlAs terahertz resonant-tunneling diode have been detected. The found oscillations are considered taking account of the LO-phonon excitation stimulated by tunneling of electrons through the quantum active region in the resonance nanostructure where an undoped quantum well layer is sandwiched between two undoped barrier layers. Rearrangements in the I-V characteristics of the resonant-tunneling diode as a consequence of the topological transformation of a measurement circuit from the circuit with the series resistance R s to the circuit with the shunt R p have been experimentally studied and analyzed. The revealed substantial changes in the current-voltage characteristics of the resonant-tunneling diode are discussed schematically using Kirchhoff's voltage law.

It is shown that using the state-of-the-art quantum interferometer (SQUID) with the resolution 10-6 Φ0 Hz-1/2 = 2.07 × 10-21 Wb Hz-1/2, coupled to a magnetostrictor, playing the role of tensomagnetic transducer, it is possible to construct a system for detecting pressure variations with the ultimate sensitivity of 10-13 Pa Hz-1/2 and for measuring specific elongation with the sensitivity of 10-24 Hz-1/2. The analysis of physical grounds of the inverse magnetostriction effect demonstrates concrete ways to essentially higher efficiency of tensomagnetic conversion. The estimates performed demonstrate the possibility of using the SQUID/magnetostrictor system as a detector of gravitational waves. Other possibilities of using this system for solving both fundamental and applied problems are also considered.

Various versions of an ultrasensitive magnetometer using a magneto-optical converter based on the Faraday effect with a field induction resolution about one picoTesla and a fiber-optic sensor with a magnetostrictive core are discussed.

When comparing the operation of a superfluid helium matter wave quantum interferometer (He SQUID) with that of an ordinary direct-current quantum interferometer (dc SQUID), we estimate their resolution limitation that correspond to quantum fluctuations. An alternative mode of operation of the interferometer as a unified macroquantum system is considered.

Photocurrents in liquid crystal cells of different structures were experimentally studied. The results of the study confirm the photorefractive mechanism of the light beam self-action in nematic liquid crystals, which consists in a decrease in the density of surface charges screening an external electric field upon light exposure. The data obtained from photoelectric and optical measurements suggest that the photorefractive effect appears in cells with different orientants and in the absence of orientant. In a planar cell oriented by rubbed polyimide, the crucial role is played by the interface between the liquid crystal and polyimide deposited on the anode.

We suggest a scheme of the Superfluid Helium Quantum Interference Device (SHeQUID) with a transformer of the angular momentum stream, whose working medium is superfluid liquid He4. A scheme is provided for measuring the Lense-Thirring effect under laboratory conditions as well as other effects related to super slow rotations.

The stability of critical parameters T c and I c of commercial high-temperature superconducting wires upon long-term passage of transport current (about 0.7 I c ) in liquid nitrogen (77 K) is studied. Voltage-current characteristics U ( I ), as well as the critical current and critical temperature, are investigated for the case of Bi(2223) hermetic multifilament wires and Dy(123) superconducting tapes covered by a thin Ag layer. In the former case, a considerable decrease in the critical current (by ~30%) and swelling of the wires after passage of the current for 323 h are observed. The same is true for a reference sample, which does not experience the action of current and stays in liquid nitrogen for 700 h. The decrease in the critical current in the Bi(2223) sam- ple is likely to be associated with penetration of a liquid coolant into the composite conductor: evaporating and expanding as a result of heating, it severely deforms the material. The Dy(123) sample grown epitaxially dem- onstrates high stability of the critical current after it has experienced the action of current for 400 h and been kept in liquid nitrogen for 1000 h.

Evidence of dark matter in the Universe is discussed and the most popular candidates for dark matter particles are reviewed. The review is mainly devoted to numerous experiments, both underway and planned, on the search for dark matter particles. Various experimental methods are discussed, including those involving direct registration of dark matter particles with the detector and those where the products of dark matter decay and annihilation are registered.

The design of a magnetic calorimeter for the measurement of releases of energy that correspond to a number of rare events, for example, cosmic particles, particles of dark matter, isolated x-ray quanta, and so on, is proposed. The calorimeter is set into a working state by means of the method of adiabatic demagnetization and the response to energy release is measured by a quantum interferometer (squid). The action of the calorimeter in different practical problems is considered, and the sensitivity of the device and its measurement precision are estimated.

The modern state of the Dark Matter (DM) problem is briefly considered. A scheme of direct detection of DM particles with the help of liquid helium is proposed. The energy sensitivity of the detector based on this scheme is estimated.

Problems of dark matter (DM) particle detection are briefly reviewed. An original two-channel scheme for direct detection of cosmic DM particles is proposed. This scheme is based on a superlow-temperature calorimeter which includes a nuclear spin system whose magnetic response is measured by a quantum interferometer (SQUID). Low threshold and the capability for efficiently suppressing the recoil-electron background are the most important advantages of the proposed scheme. They make it possible to detect DM particles in the range of extremely low recoil energies and carry out direct DM search with high sensitivity.

A scheme of magnetic calorimeter for registration of rare events characterized by small energy release (cosmic rays, WIMPs, solitary X-ray quanta) is proposed. The calorimeter is brought to operation by adiabatic demagnetization, and its magnetic response is measured by a quantum interferometer (SQUID, A. Barone and G. Paterno, Physics and applications of Josephson Effect). Special consideration is given to the specific features of calorimeter operation in the ferromagnetic transition region. The trigger registration of ultrasmall energy release by a ferromagnetic system in the metastable state is described.

By the example of experiments performed for a month before writing this paper, some features of measurement automation are considered, and solutions to some “unusual” problems using conventional methods of experiment automation are proposed. Simple circuitries using inexpensive available electronic components whose characteristics can be found in the literature accessible for non-specialists were developed [1, 2]. Some physical results obtained using the described system are considered.

The problem of numerical simulation of NRM spectra of the donor impurity in silicon is solved in the context of the fact that the system of nuclear spins of 31 P is planned to be used to organize working registers of a solid-state quantum computer. The proposed simulation method is shown to be applicable in the case of a quantitative increase of the NMR register and its topological complication. A scheme of readout of the results of “quantum counting” at a level allowing determination (with the help of SQUID) of the state of an individual spin is proposed.

The scheme of a magnetic calorimeter for recording extremely low energy releases is developed. The calorimeter is activated by the method of adiabatic demagnetisation and its response to the energy release is measured with a superconducting quantum interference device (SQUID). The estimate of the ultimate sensitivity of the calorimeter with the SQUID demonstrates the possibilities of its application for detecting ultralow radiation intensity, recording single X-ray quanta in the proportional regime and other events with ultralow energy releases. The scheme of the calorimeter with the SQUID on matter waves in superfluid 4He is proposed.

A spatially inhomogeneous state in HTSC Ba1-x KxBiO3 single crystals (T c ≈ 30 K, x = 0.4) has been studied at T < Ť ≈ 17 K, where Ť is the temperature of separation into superconducting and dielectric phases. This separation has earlier been detected in Ba1-x KxBiO3 polycrystals. In the single crystals, the main results are obtained from hysteretic magnetization reversal curves, whereas the character of separation in the polycrystals is clearly visible from I–V curves. The results obtained support the theoretical model of HTSC separation proposed in [1].

Coherent interference effects of the following three types are experimentally discovered in disordered (randomized) systems: (i) Josephson behavior of the HTSC polycrystal BaKBiO in the phase-separated state; (ii) oscillations of bismuth film resistance, which are periodic in “direct” magnetic field; and (iii) mesoscopic oscillations of the resistance in the course of film growth. In the first case, the method for detecting the “latent” nonstationary Josephson effect is substantiated by the frequency modulation method for microwave radiation, while in the other two cases, simple models are proposed to explain the nature of coherent oscillations of the resistance. The analogy between the observed oscillations and the Josephson effect in randomized systems is discussed.

In the context of all-weather tracking distant cosmic objects issues, six original schemes of detecting far-infrared radiation are presented here, which approach in their sensitivity to the level that allows their use in photon counting mode. The first one is a modernized version of the Up-converter (with the placement of nonlinear crystal/mixer inside of resonator in a single laser unit) for the transfer of far-infrared photons in the visible range, where the photon counting is possible via PMT or APD. The second scheme of registration far IR is based on the forward bias LED at a current, which is still not enough for the generation of radiation. The experiments allowed to observe photoresponse of such a system for the red border of the internal photoelectric effect. The following three schemes are cryogenic. And the last one is an Up-converter, where instead of the classical mixing on nonlinear crystal is used quantum effect of releasing energy metastable state under the influence of the far-infrared radiation quanta.

Possible approaches to improvement of quality of a high-speed planar transmission line are investigated by systematic study of superconductor high- Q microstrip resonators in the frequency range of order 10 GHz. Superconductor microstrip resonators with maximal highest quality-factors Q >10 5 were constructed. Relative contributions of spectral (geometrical and non-dissipative material properties), on one hand, and of dissipative (losses in materials) characteristics, on another hand, into the limitation of maximal achievable values of the quality of microstrip resonators are investigated. It is shown that the highest by now Q ≥10 5 are limited dominantly by the spectral properties of microstrip resonators.

Multi quantum-well long-period structures are promising for a number of important applications including the far infrared intersubband-transition-based narrow-band radiation devices, microwave resonant-tunneling and self-sustained current oscillation generators, multilevel-logic element devices based on the recently found switching effect between the multistable current states, terahertz emission detectors. All devices have in common the operation dependence on resonant-tunneling rearrangement effects in the long-period structure. We present the results of optical investigation of resonant-tunneling rearrangement processes in long-period GaAs/AlGaAs superlattice structures under application of vertical electric field by means of low-temperature photoluminescence (PL) technique in comparisons with the data of vertical transport measurements performed simultaneously on the same structures. The effect of appearance of the new PL peaks accompanied by suppression of the old ones with increasing bias voltage has been detected, resulting from the Stark shift phenomenon. PL intensity dependences on the applied voltage are presented for the first time which complement the measured current-voltage data. The transition effect from bound (exciton) to free (electron and hole) states in electric field is observed. It is shown that the optical research method can be more sensitive in some situations to provide the crucial information about the resonant-tunneling rearrangement effects even under condition when the ordinary current-voltage measurements do not reveal any features.

Thin bismuth films were deposited by pulsed laser deposition technique. The conductivity of films was measured in-situ during deposition process. Quantum oscillations of conductivity were observed. Films were investigated by photoelectron spectroscopy technique. Red shift of outer work function for about 1.5 eV for thin films was observed.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The magnetic behavior of Ba–K–Bi–O single crystals below T c was investigated. The magnetic moment hysteresis loops were examined with the help of a small Hall detector. The complex analysis of the data on the temperature dependencies of the residual magnetic moment and H c1 , obtained from the magnetic experiments, and the resistive superconducting transition curves give rise to the following picture: at T c =30 K the transition to the continuous superconducting phase takes place, while at T * =17 K one more transition happens––to the spatially inhomogeneous superconductor–insulator state, that also could be destroyed either by temperature or by magnetic field.

The existence of space inhomogeneous superconductor insulator state (SISIS) found out earlier in polycrystalline samples of high-TC system Ba0.6K0.4BiO3 (TC30 K) is confirmed on Ba0.6K0.4BiO3 single crystal. At T* (T*

The magnetic response of HTSC Ba–K–Bi–O single crystals in superconducting state was investigated with the help of a small Hall detector. The magnetic moment of the sample was measured as a function of the magnetic field up to 650 Oe and as a function of temperature while heating in the external magnetic field. Distinct paramagnetic response (PMR) was observed. In contrast to the other works where “paramagnetic Meissner effect” was noted these experiments were carried out on zero field cooled samples and the paramagnetic response was exhibited both at very low (

The results of comprehensive examinations of 13 children with orbital injuries, in whom injuries to the optic nerve were diagnosed, are analyzed. Computer-aided tomography and examinations with visual evoked potentials helped detect the signs of optic nerve injuries in the first days after the injury even in cases without ophthalmoscopic changes. Grave disorders of the involved eye visual evoked potentials were detected, that evidenced organic changes of the third neurone, despite high vision acuity. Disordered visual evoked potentials of the intact eye as against age-specific norm were detected in 8 children.

The energy resolution of the detector on the base of the magnetic adiabatic calorimeter (MAC) operating in the region of the ferromagnetic transition has been estimated on the basis of the Ginzburg-Landau theory. It is assumed that the MAC is set into operating position at low temperature by the adiabatic demagnetisation method. The magnetic response caused by the energy release at a particle entering is detected by SQUID. The estimation of the system sensibility demonstrates the feasibility of the application of the MAC as a weak interacting particles detector.

The dc-current destruction of superconducting state in Ba−K−Bi−O was registered simultaneously both by measuring V–I characteristic and magnetic susceptibility χ. The experiments were carried out on the polycrystall samples in the temperature interval 1.5–4.2 K. The hysteresis of both characteristics was observed, the temperature dependencies of hysteresis value of V–I and c-I being quiet opposite. The nonmonotonic temperature dependence of I has been found. The observed effects can be explained in the framework of the model, according to which the special nonhomogeneous state can arise—the space structure of the alternate superconducting and insulating regions with Josephson tunnelling between the former.

The method of frequency modulation of microwave radiation to observe Josephson behavior of multicircuit weak links system is suggested. The possibilities of the method are theoretically analyzed for the case of the system consisting of many Josephson contacts with random parameters. The technique was sampled on the example of polycrystalline high-T c Ba 0.6 K 0.4 BiO 3 .

The resistivity of single crystals of the cubic high temperature superconductor Ba0.6K0.4BiO3 with Tc=30 K has been measured in the temperature range from 4.2 to 300 K. The experimental curve is well approximated in the framework of the classical electron-phonon model of resistivity by the Gruneisen type dependence using the phonon spectrum in the form of an acoustical branch and a widely separated narrow optical peak.

A peculiar form of sclerodermia is described in a 10 year girl. Initially, the disease pronounced itself with focal epileptic spells involving lated the focal sclerodermia and facial hemiatrophy. The peculiar feature of the case is the bilateral uveitis and subclinical serose meningitis. Brain CT scans and Doppler investigation of extracranial carotid and vertebral arteries were performed.