arXiv subjects

Sergey Uchaikin

Publications and source records attributed to Sergey Uchaikin.

9 recordsLinked to original sources

arXiv2026

Extended High-Mass Axion Search with an Auxetically Tuned Higher-Order-Mode Cavity

Conventional high-mass axion haloscopes based on the TM$_{010}$ mode lose detection volume as the resonant frequency increases. We report an extended axion search using a dielectric-restored TM$_{020}$ cavity haloscope with symmetry-preserving auxetic tuning based on a single-degree-of-freedom mechanical architecture. Using a near-quantum-limited microwave receiver, we searched a frequency range of 4.98-5.07 GHz and exclude axion-photon couplings with sensitivity approaching the KSVZ benchmark. Together with two earlier searches, the present scans extend a multi-scan program based on this architecture, yielding nearly 300 MHz of contiguous high-mass axion coverage over 4.98-5.27 GHz, the first broad search reported with a single higher-order-mode haloscope. This work establishes higher-order-mode cavities as a practical, scalable route beyond the TM$_{010}$ volume penalty.

hep-ex↗

arXiv2026

Search for Axion Dark Matter around \texorpdfstring{$15.6\,\mu\text{eV}$}{15.6 microeV} with a Broadly Tunable High-Temperature Superconducting Cavity

We report an axion dark matter search in the mass range of $15.30\text{--}15.85\,\mu\text{eV}$ using a broadly tunable high-temperature superconducting (HTS) haloscope. By soldering substrate-stripped rare-earth barium copper oxide (REBCO) films onto a copper shell, we achieved a quality factor 3--4 times higher than in copper cavities across its tuning band in an 8\text{-T} magnetic field. We set robust Frequentist 90\%~confidence-level exclusion limits on the axion--photon coupling down to 1.3 times the KSVZ coupling, while a complementary Bayesian analysis achieves KSVZ-level sensitivity.

hep-ex↗

arXiv2026

Multi-tesla operation of high-temperature superconducting cavities for accelerated axion dark matter searches

Axion haloscopes use radio-frequency cavities immersed in a magnetic field to search for dark-matter axions, which could resolve two central puzzles in fundamental physics: the strong charge-parity problem in quantum chromodynamics and the nature of dark matter. Multi-tesla fields trigger axion-to-photon conversion but induce severe vortex dissipation in standard superconductors, whereas copper cavities are limited by the anomalous skin effect ($Q \lesssim 10^5$). Here, we overcome these barriers by introducing a pole-to-pole 3-dimensional cavity architecture constructed from strain-controlled, mechanically delaminated rare-earth barium copper oxide (REBCO) tapes. By selectively stripping the lossy metallic substrate while utilizing the copper stabilizer as a "conductive backing" we convert the longitudinal assembly gaps into waveguides below cutoff, effectively suppressing cross-seam RF leakage. Employing a two-track strategy, we first unveiled the intrinsic high-field potential of the material with a 5.4 GHz resonant cavity, achieving an unloaded quality-factor ($Q_0$) of $1.4 \times 10^7$ in an 8 T magnetic field, exceeding conventional copper baselines by two orders of magnitude. Second, prioritizing practical haloscope integration, we engineered a tunable, volume-maximized 2.3 GHz pathfinder cavity. Deployed in the Pilot Axion Cavity Experiment at the Center for Axion and Precision Physics Research (CAPP-PACE), this system achieved a 180 mK noise temperature and a 5-fold $Q$ enhancement over copper, cumulatively delivering a $\sim$8.4-fold scan-rate acceleration.

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arXiv2025

Search for high-frequency gravitational waves via re-analysis of cavity axion data

Monochromatic high-frequency gravitational waves (HFGW) provide a distinctive probe of new physics scenarios, most notably axion clouds around rotating black holes formed via superradiance. We reanalyzed data from the CAPP-12T MC (multi-cell) axion haloscope experiment [Phys. Rev. Lett. 133,051802 (2024)]. The study covers a continuous $2\,$MHz frequency span centered at $5.311\,$GHz. No rescan candidates were found, and we set 90% confidence-level exclusion limits on the gravitational-wave strain, reaching $h_0 \approx 3.9 \times 10^{-21}$ in the most sensitive regions of the sky. Interpreted in the context of black-hole superradiance from axion clouds, the results exclude black holes with mass $M_{\mathrm{BH}} \simeq 1.22 \times 10^{-6}\,M_\odot$ within distances of $O(10^{-2})\,$AU from Earth, under benchmark assumptions. This work demonstrates the potential of electromagnetic resonant cavities as novel detectors of monochromatic HFGW and motivates future searches for both long-lived and transient signals.

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arXiv2025

Axion Dark Matter Search with Near-KSVZ Sensitivity Using the TM$_{020}$ Mode

Dark matter remains one of the most profound mysteries in modern physics, with axions, a hypothetical particle proposed to resolve the strong CP problem, standing as a compelling candidate. Among various experimental strategies, cavity haloscopes currently offer the most sensitive method to detect axions, though their searches have largely been confined to axion masses below 10 $μ$eV. However, recent theoretical developments suggest that the axion mass lies beyond this range. Higher-order cavity modes have been explored as a methodological approach to expand the search range, albeit with limited success in achieving both high sensitivity and broad tunability. In this work, we present a sensitive search for axions with masses around 21 $μ$eV, utilizing the TM$_{020}$ mode of a cylindrical cavity, which incorporated an innovative tuning mechanism. Our results reached 1.7 times the KSVZ sensitivity over 100 MHz, representing a significant improvement in this mass range and contributing to the experimental search for axion dark matter at higher masses.

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arXiv2024

Experimental search for invisible dark matter axions around 22 μeV

The axion has emerged as the most attractive solution to two fundamental questions in modern physics related to the charge-parity invariance in strong interactions and the invisible matter component of our universe. Over the past decade, there have been many theoretical efforts to constrain the axion mass based on various cosmological assumptions. Interestingly, different approaches from independent groups produce good overlap between 20 and 30 μeV. We performed an experimental search to probe the presence of dark matter axions within this particular mass region. The experiment utilized a multi-cell cavity haloscope embedded in a 12 T magnetic field to seek for microwave signals induced by the axion-photon coupling. The results ruled out the KSVZ axions as dark matter over a mass range between 21.86 and 22.00 μeV at a 90% confidence level. This represents a sensitive experimental search guided by specific theoretical predictions

hep-ex↗

arXiv2024

Parameter optimization of Josephson parametric amplifiers using a heuristic search algorithm for axion haloscope search

The cavity haloscope is among the most widely adopted experimental platforms designed to detect dark matter axions with its principle relying on the conversion of axions into microwave photons in the presence of a strong magnetic field. The Josephson parametric amplifier (JPA), known for its quantum-limited noise characteristics, has been incorporated in the detection system to capture the weakly interacting axion signals. However, the performance of the JPA can be influenced by its environment, leading to potential unreliability of a predefined parameter set obtained in a specific laboratory setting. Furthermore, conducting a broadband search requires consecutive characterization of the amplifier across different tuning frequencies. To ensure more reliable measurements, we utilize the Nelder-Mead technique as a numerical search method to dynamically determine the optimal operating conditions. This heuristic search algorithm explores the multidimensional parameter space of the JPA, optimizing critical characteristics such as gain and noise temperature to maximize signal-to-noise ratios for a given experimental setup. Our study presents a comprehensive analysis of the properties of a flux-driven JPA to demonstrate the effectiveness of the algorithm. This approach contributes to ongoing efforts in axion dark matter research by offering an efficient method to enhance axion detection sensitivity through the optimized utilization of JPAs.

physics.ins-det↗

arXiv2022

Near-Quantum-Noise Axion Dark Matter Search at CAPP around 9.5 $μ$eV

We report the results of an axion dark matter search over an axion mass range of 9.39-9.51 $μ$eV. A flux-driven Josephson parametric amplifier (JPA) was added to the cryogenic receiver chain. A system noise temperature of as low as 200 mK was achieved, which is the lowest recorded noise among published axion cavity experiments with phase-insensitive JPA operation. In addition, we developed a two-stage scanning method which boosted the scan speed by 26%. As a result, a range of two-photon coupling in a plausible model for the QCD axion was excluded with an order of magnitude higher in sensitivity than existing limits.

hep-ex↗

arXiv2021

First Results from Axion Haloscope at CAPP around 10.7 $μ$eV

The Center for Axion and Precision Physics research at the Institute for Basic Science is searching for axion dark matter using ultra-low temperature microwave resonators. We report the exclusion of the axion mass range 10.7126$-$10.7186 $μ$eV with near Kim-Shifman-Vainshtein-Zakharov (KSVZ) coupling sensitivity and the range 10.16$-$11.37 $μ$eV with about 9 times larger coupling at 90$\%$ confidence level. This is the first axion search result in these ranges. It is also the first with a resonator physical temperature of less than 40 mK.

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