arXiv subjects

O. G. Turutanov

Publications and source records attributed to O. G. Turutanov.

13 recordsLinked to original sources

arXiv2025

The Nobel Prize in physics and the contribution of Ukrainian scientists to the understanding of quantum phenomena, in particular the behavior of macroscopic systems (The 2025 Nobel Prize in Physics)

The Nobel Prize in Physics 2025 has been awarded to John Clarke, John Martinis, and Michel Devoret for "the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit". Their achievements open up possibilities for developing the next generation of quantum technologies, including quantum cryptography, quantum computers, and quantum sensors. This article explains physical grounds of these discoveries and describes the role of earlier studies of weak superconductivity and macroscopic quantum systems by other scientists, highlighting the contribution of researchers from the B.I. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, who obtained pioneering results in this field. The paper includes short biographies of the Nobel laureates.

cond-mat.supr-con↗

arXiv2025

Chronicle: "Foot of the iceberg" of Nobel Prize in Physics 2025: ILTPE and LTP contribution

The Nobel Prize in Physics 2025 has been awarded to John Clarke, John Martinis, and Michel Devoret for "the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit". The paper explains the essence of their studies and shows in a historical context the importance of earlier research in superconductivity and quantum physics of macroscopic systems by other physicists, particularly, Ukrainian scientists, including employees of the B. Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine (ILTPE). The role of the Fizyka Nyzkykh Temperatur (FNT) journal issued by ILTPE in Kharkiv and its translation as AIP Low Temperature Physics (LTP) in dissemination of results of the theoretical and experimental studies in the field is emphasized as well.

cond-mat.supr-con↗

arXiv2024

Some aspects of resistive-to-normal state transition by direct and microwave currents in superconducting thin films with phase slip lines

Based on analysis of current-voltage characteristics and imaging of the resistive state of thin-film tin strips using the low-temperature laser scanning microscopy (LTLSM), the process of destruction of superconductivity by current and microwave irradiation with the formation and spatial rearrangement of the order parameter phase slip lines, and their transformation into discrete localized normal domains is shown. The prospects of LTLSM are considered form the point of view of study of the high-frequency properties of superconducting structures and spatial characteristics in the pre-critical state for instrumental applications.

cond-mat.supr-con↗

arXiv2023

Design of deeply cooled ultra-low dissipation amplifier and measuring cell for quantum measurements with a microwave single-photon counter

The requirements and details of designing a measuring cell and low-back-action deeply-cooled amplifier for quantum measurements at 10 mK are discussed. This equipment is a part of a microwave single-photon counter based on a superconducting flux qubit. The high electron mobility transistors (HEMTs) in the amplifier operate in unsaturated microcurrent regime and dissipate only 1 microwatt of dc power per transistor. Simulated amplifier gain is 15 dB at 450 MHz with a high-impedance (~5 kOhm signal source and standard 50-Ohm output.

quant-ph↗

arXiv2022

Superconducting source and sensor of single bubbles to study nucleate boiling of liquid helium

Joule heat generated by resistive elements of cryogenic micro- and nanodevices often originates boiling of the cooling cryogenic liquids (helium, nitrogen). The article proposes an experimental method to explore the dynamics of the formation and development of a single vapor bubble in cryogenic liquid by sensing the temperature change of a superconducting thin-film microbridge being in the resistive state with single phase-slip center or line. It serves both the source of heat for generating single bubbles and the surface temperature sensor due to its temperature-dependant excess current. The average bubble detachment rate and the average single bubble volume were experimentally determined for nucleate helium boiling. The obtained values are in good agreement with the data of other authors found in literature.

cond-mat.supr-con↗

arXiv2022

Spatial characterization of the edge barrier in wide superconducting films

The current-induced destruction of superconductivity is discussed in wide superconducting thin film strips, whose width is greater than the magnetic field penetration depth, in weak magnetic fields. Particular attention is paid to the role of the edge potential barrier (the Bean-Livingston barrier) in critical state formation and detection of the edge responsible for this critical state with different mutual orientations of external perpendicular magnetic field and transport current. Critical and resistive states of the thin film strip were visualized using the space-resolving low-temperature laser scanning microscopy (LTLSM) method, which enables detection of critical current-determining areas on the thin film edges. Based on these observations, a simple technique was developed for investigation of the critical state separately at each film edge, and for the estimation of residual magnetic fields in cryostats. The proposed method only requires recording of the current-voltage characteristics of the thin film in a weak magnetic field, thus circumventing the need for complex LTLSM techniques. Information thus obtained is particularly important for interpretation of studies of superconducting thin film single-photon light emission detectors.

cond-mat.supr-con↗

arXiv2021

Ultra-low supply voltage crystal quartz oscillator

An ultra-low-voltage crystal quartz oscillator is proposed. The approach to its design is essentially based on using a HEMT operating in unsaturated dc regime and a quartz resonator as a resonant impedance transformer. The 25 MHz prototype shows steady oscillations at the supply voltage of less than 17 mV and the power consumption as low as 300 nW, i.e., 1-2 orders of magnitude lower than other to-date oscillators. This approach is good for building ultra-low consumption radio devices including those working at low temperatures.

physics.ins-det↗

arXiv2015

Stochastic amplification of weak signals in an RF SQUID with ScS contact

The paper presents results of a numerical simulation of the stochastic dynamics of magnetic flux in an RF SQUID loop with a Josephson point (ScS) contact driven by a mix of band-limited Gaussian noise and low-frequency small-amplitude sine signal, at finite temperatures $0<T<T_{c}$. A change in the gain of the stochastically amplified weak signal with the temperature rise is shown to be due to smearing of the energy barrier between adjacent metastable current states of the loop. A comparison to an RF SQUID with a tunnel (SIS) junction is done.

cond-mat.supr-con↗

arXiv2015

Measurement of brightness temperature of two-dimensional electron gas in channel of a high electron mobility transistor at ultralow dissipation power

A technically simple and physically clear method is suggested for the direct measurement of brightness temperature of two-dimensional electron gas (2DEG) in the channel of a high electron mobility transistor (HEMT). The usage of the method was demonstrated with the pseudomorphic HEMT as a specimen. The optimal HEMT dc regime, from the point of view of the "back action" problem, was found to belong to the unsaturated area of the static characteristics possibly corresponding to the ballistic electron transport mode. The proposed method is believed to be a convenient tool to explore the ballistic transport, electron diffusion, 2DEG properties and other electrophysical processes in the heterostructures.

cond-mat.mes-hall↗

arXiv2014

Experimental observation of induced stochastic transitions in multi-well potential of RF SQUID loop

An amplification of a weak low-frequency harmonic signal is experimentally observed in a single-junction-superconducting quantum interferometer (RF SQUID loop) due to stochastic transitions between two or more metastable states of the loop under the applied noise flux of varying intensity (the effect of stochastic resonance, SR). In addition to the usual scenario of the SR in a bistable system with Gaussian noise, the transitions between multiple metastable states of the multi-well SQUID loop potential under the influence of a binary noise is observed. This can be interpreted as a kind of noise "spectroscopy" of the metastable states of the SQUID loop with different values of the trapped magnetic flux.

cond-mat.supr-con↗

arXiv2014

Stochastic resonance in an RF SQUID with shunted ScS junction

Using a point (superconductor-constriction-superconductor, ScS) contact in a single-Josephson-junction superconducting quantum interference device (RF SQUID) provides stochastic resonance conditions at any arbitrary small value of loop inductance and contact critical current, unlike SQUIDs with more traditional tunnel (superconductor-insulator-superconductor, SIS) junctions. This is due to the unusual potential energy of the ScS RF SQUID which always has a barrier between two wells thus making the device bistable. This paper presents the results of a numerical simulation of the stochastic dynamics of the magnetic flux in an ScS RF SQUID loop affected by band-limited white Gaussian noise and low-frequency sine signals of small and moderate amplitudes. The difference in stochastic amplification of RF SQUID loops incorporating ScS and SIS junctions is discussed.

cond-mat.supr-con↗

arXiv2012

Quantum superposition of three macroscopic states and superconducting qutrit detector

Superconducting quantum coherent circuits have opened up a novel area of fundamental low-temperature science since they could potentially be the element base for future quantum computers. Here we report a quasi-three-level coherent system, the so-called superconducting qutrit, which has some advantages over a two-level information cell (qubit), and is based on the qutrit readout circuit intended to measure individually the states of each qubit in a quantum computer. The designed and implemented radio-frequency superconducting qutrit detector (rf SQUTRID) with atomic-size ScS-type contact utilizes the coherent-state superposition in the three-well potential with energy splitting Delta E_01/k_B=1.5 K at the 30th quantized energy level with good isolation from the electromagnetic environment. The reason why large values of Delta E_01 (and thus using atomic-size Nb-Nb contact) are required is to ensure an adiabatic limit for the quantum dynamics of magnetic flux in the rf SQUTRID.

cond-mat.supr-con↗

arXiv2005

Laser Scanning Microscopy of HTS Films and Devices

The work describes the capabilities of Laser Scanning Microscopy (LSM) as a spatially resolved method of testing high_Tc materials and devices. The earlier results obtained by the authors are briefly reviewed. Some novel applications of the LSM are illustrated, including imaging the HTS responses in rf mode, probing the superconducting properties of HTS single crystals, development of twobeam laser scanning microscopy. The existence of the phase slip lines mechanism of resistivity in HTS materials is proven by LSM imaging.

cond-mat.supr-con↗