| 1. |
- Anders, S., et al.
(author)
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European roadmap on superconductive electronics - Status and perspectives
- 2010
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In: Physica C: Superconductivity and its Applications. - : Elsevier BV. - 0921-4534. ; 470:23-24, s. 2079-2126
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Journal article (peer-reviewed)abstract
- For four decades semiconductor electronics has followed Moore's law: with each generation of integration the circuit features became smaller, more complex and faster. This development is now reaching a wall so that smaller is no longer any faster. The clock rate has saturated at about 3-5 GHz and the parallel processor approach will soon reach its limit. The prime reason for the limitation the semiconductor electronics experiences is not the switching speed of the individual transistor, but its power dissipation and thus heat. Digital superconductive electronics is a circuit- and device-technology that is inherently faster at much less power dissipation than semiconductor electronics. It makes use of superconductors and Josephson junctions as circuit elements, which can provide extremely fast digital devices in a frequency range - dependent on the material - of hundreds of GHz: for example a flip-flop has been demonstrated that operated at 750 GHz. This digital technique is scalable and follows similar design rules as semiconductor devices. Its very low power dissipation of only 0.1 mu W per gate at 100 GHz opens the possibility of three-dimensional integration. Circuits like microprocessors and analogue-to-digital converters for commercial and military applications have been demonstrated. In contrast to semiconductor circuits, the operation of superconducting circuits is based on naturally standardized digital pulses the area of which is exactly the flux quantum Phi(0). The flux quantum is also the natural quantization unit for digital-to-analogue and analogue-to-digital converters. The latter application is so precise, that it is being used as voltage standard and that the physical unit 'Volt' is defined by means of this standard. Apart from its outstanding features for digital electronics, superconductive electronics provides also the most sensitive sensor for magnetic fields: the Superconducting Quantum Interference Device (SQUID). Amongst many other applications SQUIDs are used as sensors for magnetic heart and brain signals in medical applications, as sensor for geological surveying and food-processing and for non-destructive testing. As amplifiers of electrical signals. SQUIDs can nearly reach the theoretical limit given by Quantum Mechanics. A further important field of application is the detection of very weak signals by 'transition-edge' bolo-meters, superconducting nanowire single-photon detectors, and superconductive tunnel junctions. Their application as radiation detectors in a wide frequency range, from microwaves to X-rays is now standard. The very low losses of superconductors have led to commercial microwave filter designs that are now widely used in the USA in base stations for cellular phones and in military communication applications. The number of demonstrated applications is continuously increasing and there is no area in professional electronics, in which superconductive electronics cannot be applied and surpasses the performance of classical devices. Superconductive electronics has to be cooled to very low temperatures. Whereas this was a bottleneck in the past, cooling techniques have made a huge step forward in recent years: very compact systems with high reliability and a wide range of cooling power are available commercially, from microcoolers of match-box size with milli-Watt cooling power to high-reliability coolers of many Watts of cooling power for satellite applications. Superconductive electronics will not replace semiconductor electronics and similar room-temperature techniques in standard applications, but for those applications which require very high speed, low-power consumption, extreme sensitivity or extremely high precision, superconductive electronics is superior to all other available techniques. To strengthen the European competitiveness in superconductor electronics research projects have to be set-up in the following field: - Ultra-sensitive sensing and imaging. - Quantum measurement instrumentation. - Advanced analogue-to-digital converters. - Superconductive electronics technology.
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| 2. |
- Yablokov, Anton A., et al.
(author)
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Resonant response drives sensitivity of Josephson escape detector
- 2021
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In: Chaos, Solitons and Fractals. - : Elsevier BV. - 0960-0779. ; 148
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Journal article (peer-reviewed)abstract
- The Josephson junction as a switching detector of weak signals is investigated in presence of noise in the frame of rotating pendulum model. The parameter range, where the detection can be more efficient, is found. It has been demonstrated, that with decrease of the signal power the double minima of the mean switching time and the standard deviation are transformed into a single minimum, which corresponds to interplay between noise suppression and resonant activation regimes. The resonant nature of escape allows to detect weak signals, whose amplitudes are weaker than the difference between critical current and bias current of a Josephson junction. With decrease of damping an efficient detection becomes possible even at subharmonics of the resonance frequency.
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| 3. |
- Golubev, Dmitry, et al.
(author)
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Single-Photon Detection with a Josephson Junction Coupled to a Resonator
- 2021
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In: Physical Review Applied. - 2331-7019. ; 16:1
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Journal article (peer-reviewed)abstract
- We use a semiclassical formalism to optimize a microwave single-photon detector based on switching events of a current-biased Josephson junction coupled to a resonator. To detect very rare events, the average time between dark counts τdark should be maximized taking into account that the switching time τsw should be sufficiently small. We demonstrate that these times can be tuned in a wide range by changing the junction parameters, and τdark/τsw∼109 can be achieved. Therefore, a junction-resonator arrangement can be used to detect extremely low photon fluxes (e.g., for searching for galactic axions).
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| 4. |
- Kern, S., et al.
(author)
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Reflection-enhanced gain in traveling-wave parametric amplifiers
- 2023
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In: Physical Review B. - 2469-9969 .- 2469-9950. ; 107:17
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Journal article (peer-reviewed)abstract
- The operating principle of traveling-wave parametric amplifiers is typically understood in terms of the standard coupled mode theory, which describes the evolution of forward propagating waves without any reflections, i.e., for perfect impedance matching. However, in practice, superconducting microwave amplifiers are unmatched nonlinear finite-length devices, where the reflecting waves undergo complex parametric processes, not described by the standard coupled mode theory. Here, we present an analytical solution for the TWPA gain, which includes the interaction of reflected waves. These reflections result in corrections to the well-known results of the standard coupled mode theory, which are obtained for both three-wave and four-wave mixing processes. Due to these reflections, the gain is enhanced and unwanted nonlinear phase modulations are suppressed. Predictions of the model are experimentally demonstrated on two types of unmatched TWPA, based on coplanar waveguides with a central wire consisting of (i) a high kinetic inductance superconductor, and (ii) an array of 2000 Josephson junctions.
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| 5. |
- Oelsner, G., et al.
(author)
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Underdamped Josephson junction as a switching current detector
- 2013
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 103:14
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Journal article (peer-reviewed)abstract
- We demonstrate the narrow switching distribution of an underdamped Josephson junction from the zero to the finite voltage state at millikelvin temperatures. We argue that such junctions can be used as ultrasensitive detectors of the single photons in the GHz range, operating close to the quantum limit: a given initial (zero voltage) state can be driven by an incoming signal to the finite voltage state. The width of the switching distribution at a nominal temperature of about T = 10 mK was 4.5 nA, which corresponds to an effective noise temperature of the device below 60 mK. (C) 2013 AIP Publishing LLC.
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| 6. |
- Pankratov, A. L., et al.
(author)
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Towards a microwave single-photon counter for searching axions
- 2022
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In: npj Quantum Information. - : Springer Science and Business Media LLC. - 2056-6387. ; 8:1
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Journal article (peer-reviewed)abstract
- The major task of detecting axions or axion-like particles has two challenges. On the one hand, the ultimate sensitivity is required, down to the energy of a single microwave photon of the yoctojoule range. On the other hand, since the detected events are supposed to be rare, the dark count rate of the detector must be extremely low. We show that this trade-off can be approached due to the peculiar switching dynamics of an underdamped Josephson junction in the phase diffusion regime. The detection of a few photons' energy at 10 GHz with dark count time above 10 s and the efficiency close to unity was demonstrated. Further enhancements require a detailed investigation of the junction switching dynamics.
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| 7. |
- Soloviev, I.I., et al.
(author)
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Effect of Cherenkov radiation on the jitter of solitons in the driven underdamped Frenkel-Kontorova model
- 2013
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In: Physical Review E. - 2470-0045 .- 2470-0053. ; 87:6
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Journal article (peer-reviewed)abstract
- The effect of complex dynamics of solitons on the output noise of the system (thermal jitter) is studied in the frame of the driven underdamped Frenkel-Kontorova model. In contrast to the continuous case, we have observed a dramatic splash of the jitter. It is demonstrated that this jitter increase is related to the joining of an initial soliton with the one generated by large amplitude oscillations of the Cherenkov radiation tail, which results in the establishment of a unified soliton structure.
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| 8. |
- Soloviev, , II, et al.
(author)
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Soliton scattering as a measurement tool for weak signals
- 2015
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In: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 92:1
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Journal article (peer-reviewed)abstract
- We have considered relativistic soliton dynamics governed by the sine-Gordon equation and affected by short spatial inhomogeneities of the driving force and thermal noise. Developed analytical and numerical methods for calculation of soliton scattering at the inhomogeneities allowed us to examine the scattering as a measurement tool for sensitive detection of polarity of the inhomogeneities. We have considered the superconducting fluxonic ballistic detector as an example of the device in which the soliton scattering is utilized for quantum measurements of superconducting flux qubits. We optimized the soliton dynamics for the measurement process varying the starting and the stationary soliton velocity as well as configuration of the inhomogeneities. For experimentally relevant parameters we obtained the signal-to-noise ratio above 100 reflecting good practical usability of the measurement concept.
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