arXiv subjects

Kirill Petrovnin

Publications and source records attributed to Kirill Petrovnin.

6 recordsLinked to original sources

arXiv2026

Phase-sensitive cascade quantum amplifier with nearly noiseless operation

Phase-sensitive parametric devices enable quadrature-selective amplification with the potential for sub-quantum-limited noise performance. In this work, we investigate the operation of a SQUID-based Josephson Parametric Amplifier (JPA), comparing its performance in the phase-preserving and phase-sensitive regimes. The device, fabricated using VTT SWAPS technology, is driven in a three-wave mixing configuration and characterized in a reflection-based measurement setup at millikelvin temperatures. To directly probe the noise performance at low JPA gains, we employ a cascaded amplification scheme in which a Traveling-Wave Parametric Amplifier (TWPA) provides low-noise pre-amplification of the JPA output. In a phase-preserving operation, the JPA exhibits near-quantum-limited performance with a system noise temperature of $351\pm53$ mK at 6 GHz. In contrast, phase-sensitive operation yields a minimum system noise temperature of $94\pm12$ mK, well below the standard quantum limit of 288 mK. Our results demonstrate that a JPA-TWPA amplifier cascade opens the door to direct, high-fidelity probing of quantum devices without the need for background noise subtraction.

quant-ph↗

arXiv2026

Bipartite entanglement under frequency comb pumping in parametric Josephson circuits

The creation of high-quality cluster states in superconducting microwave circuits is a relevant ingredient in continuous-variable quantum computing. Although large-scale cluster states have been established in optical systems, dissipation prevents their direct applicability to the microwave realm. Recent improvements in superconducting parametric circuits, in particular Josephson parametric amplifiers (JPA) and traveling wave parametric amplifiers (TWPA), have permitted substantial progress in producing entangled states using microwave photons. In this paper, we examine experimentally and theoretically the effects of numerous parametric pump tones on the degree of two-mode squeezing in a quantum circuit and apply it to the JPA. We find that additional pumps diminish the initial two-mode correlations achieved with a single pump by redistributing it among a larger network of modes and by introducing entanglement with additional idler frequencies. Taking into account the actual heterodyne measurement conditions, the experimental results are consistent with theoretical expectations.

quant-ph↗

arXiv2026

Numerical simulation methods for quantum sensing at parametric criticality

Microwave photon detection is a key technology for low-temperature superconducting electronics and quantum information processing. A promising possibility is to use switching processes in parametric superconducting devices at criticality, which can be triggered by small perturbations. Here we demonstrate the unique sensing properties of the superconducting Kerr parametric resonator when operated in the proximity of the phase transition boundary. We utilize a semiclassical approximation to provide numerical and analytical results for the Heisenberg-Langevin and Fokker-Planck equations that describe the switching mechanism. We show that the probability of switching events is enhanced by probe input states with energies down to single quanta levels.

quant-ph↗

arXiv2025

Microwave photon detection at parametric criticality

The detection of microwave fields at single-photon power levels is a much sought-after technology, with practical applications in nanoelectronics and quantum information science. Here we demonstrate a simple yet powerful criticality-enhanced method of microwave photon detection by operating a magnetic-field tunable Kerr Josephson parametric amplifier at the border of a first-order phase transition and close to the critical point. We obtain a 73\% efficiency and a dark-count rate of 167 kHz, corresponding to a responsivity of $1.3 \times 10^{17}~\mathrm{W}^{-1}$ and noise-equivalent power of 3.28 zW/$\sqrt{\rm Hz}$. We verify the single-photon operation by extracting the Poissonian statistics of a coherent probe signal.

quant-ph↗

arXiv2023

Microwave Gaussian quantum sensing with a CNOT gate receiver

In quantum illumination (QI) the non-classical correlations between continuous variable (CV) entangled modes of radiation are exploited to detect the presence of a target embedded in thermal noise. The extreme environment where QI outperforms its optimal classical counterpart suggests that applications in the microwave domain would benefit the most from this new sensing paradigm. However all the proposed QI receivers rely on ideal photon counters or detectors, which are not currently feasible in the microwave domain. Here we propose a new QI receiver that utilizes a CV controlled not gate (CNOT) in order to perform a joint measurement on a target return and its retained twin. Unlike other QI receivers, the entire detection process is carried out by homodyne measurements and square-law detectors. The receiver exploits two squeezed ancillary modes as a part of the gate's operation. These extra resources are prepared offline and their overall gain is controlled passively by a single beamsplitter parameter. We compare our model to other QI receivers and demonstrate its operation regime where it outperforms others and achieves optimal performance. Although the main focus of this study is microwave quantum sensing applications, our proposed device can be built as well in the optical domain, thus rendering it as a new addition to the quantum sensing toolbox in a wider sense.

quant-ph↗

arXiv2022

Broadband continuous variable entanglement generation using Kerr-free Josephson metamaterial

Entangled microwave photons form a fundamental resource for quantum information processing and sensing with continuous variables. We use a low-loss Josephson metamaterial comprising superconducting, non-linear, asymmetric inductive elements to generate frequency-entangled photons from vacuum fluctuations at a rate of 2 giga entangled bits per second spanning over 4 GHz bandwidth. The device is operated as a traveling wave parametric amplifier under Kerr-relieving biasing conditions. Furthermore, we realize the first successfully demonstration of single-mode squeezing in such devices -- $3.1\pm0.7$\,dB below the zero-point level at half of modulation frequency.

quant-ph↗