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We report the first search results for axion dark matter using an 18 T high-temperature superconducting magnet haloscope. The scan frequency ranges from 4.7789 to 4.8094 GHz. No significant signal consistent with the Galactic halo dark matter axion is observed. The results set the best upper bound of axion-photon-photon coupling (g_{aγγ}) in the mass ranges of 19.764 to 19.771 μeV (19.863 to 19.890 μeV) at 1.5×|g_{aγγ}^{KSVZ}| (1.7×|g_{aγγ}^{KSVZ}|), and 19.772 to 19.863 μeV at 2.7×|g_{aγγ}^{KSVZ}| with 90% confidence level, respectively. This remarkable sensitivity in the high mass region of dark matter axion is achieved by using the strongest magnetic field among the existing haloscope experiments and realizing a low-noise amplification of microwave signals using a Josephson parametric converter.
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http://dx.doi.org/10.1103/PhysRevLett.128.241805 | DOI Listing |
Nature
September 2025
Centre for Astrophysics Research (CAR), University of Hertfordshire, Hatfield, UK.
Globular clusters (GCs) are among the oldest and densest stellar systems in the Universe, yet how they form remains a mystery. Here we present a suite of cosmological simulations in which both dark-matter-free GCs and dark-matter-rich dwarf galaxies naturally emerge in the Standard Cosmology. We show that these objects inhabit distinct locations in the size-luminosity plane and that they have similar ages, age spread, metallicity and metallicity spread to globulars and dwarfs in the nearby Universe.
View Article and Find Full Text PDFLight Sci Appl
September 2025
Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin, China.
Photon upconversion through high harmonic generation, multiphoton absorption, Auger recombination and phonon scattering performs a vital role in energy conversion and renormalization. Considering the reduced dielectric screening and enhanced Coulomb interactions, semiconductor monolayers provide a promising platform to explore photon upconversion at room temperature. Additionally, two-photon upconversion was recently demonstrated as an emerging technique to probe the excitonic dark states due to the extraordinary selection rule compared with conventional excitation.
View Article and Find Full Text PDFRep Prog Phys
September 2025
Physics Department and Center for Experimental Nuclear Physics and Astrophysics, University of Washington, box 351560, Seattle, Washington, 98195-1560, UNITED STATES.
Proposed half a century ago, the quantum chromodynamics (QCD) axion explains the lack of charge and parity violation in the strong interactions and is a compelling candidate for cold dark matter. The last decade has seen the rapid improvement in the sensitivity and range of axion experiments, as well as developments in theory regarding consequences of axion dark matter. We review here the astrophysical searches and theoretical progress regarding the QCD axion.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
University of Oxford, Astrophysics, DWB, Keble Road, Oxford OX1 3RH, United Kingdom.
The recent observational evidence of deviations from the Lambda cold dark matter model points toward the presence of evolving dark energy. The simplest possibility consists of a cosmological scalar field φ, dubbed "quintessence," driving the accelerated expansion. We assess the evidence for the existence of such a scalar field.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
University of Zürich, Department of Physics, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
We present the first results from the Quantum Resolution-Optimized Cryogenic Observatory for Dark matter Incident at Low Energy (QROCODILE). The QROCODILE experiment uses a microwire-based superconducting nanowire single-photon detector (SNSPD) as a target and sensor for dark matter scattering and absorption, and is sensitive to energy deposits as low as 0.11 eV.
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