arXiv subjects

V. Yu. Lyakhno

Publications and source records attributed to V. Yu. Lyakhno.

5 recordsLinked to original sources

arXiv2025

Control of the effective value of the critical current of the RF SQUID by the high-frequency electromagnetic field

An analysis of the influence of the high-frequency electromagnetic field on the amplitude-frequency and signal characteristics of RF SQUID and experimental verification are carried out. At low parameter , the RF SQUID behavior is well described analytically by the theoretical model. In experiment, basic operation scheme is used in which the interferometer is inductively connected to a resonant tank circuit driven by RF current at a frequency close to the resonance frequency of the tank. It is shown that parameter , which distinguishes between hysteretic and non-hysteretic regimes, can be effectively adjusted to a desired value by applying the high-frequency field of a certain amplitude and frequency much higher than tank resonant frequency. A significant increase in the conversion factor and sensitivity of the RF SQUID during this adjustment is discussed.

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↗

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↗

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↗