A large area superconducting Athermal Phonon Detector (APD), which consists of Aluminum phonon/photon collection fins and Transition-Edge Sensors (TESs), is an advanced particle detection technology which enables light dark matter searches with a sub-eV resolution. While it is well known that a lower transition temperature (Tc) in a TES enhances detection sensitivity, recent experimental data...
Hafnium (Hf) is a superconducting material that has been gaining popularity among the superconducting detector community โ for e.g. TES bolometers (Rotermund et al. in prep), TES calorimeters (Lita et al. 2009, Safonova et al. 2024), optical and near-IR MKIDs (Zobrist et al. 2019, Coiffard et al. 2020), phonon-sensitive MKIDs (Li et al. in prep), STJ (STAR Cryoelectronics SBIR awarded 2022),...
The scalability of sub-Kelvin superconducting sensors is generally limited by their associated superconducting readout electronics, motivating multiplexing schemes which reduce the system complexity, cost, and thermal load on the refrigerator. Microwave SQUID multiplexing, which inherently has access to ~100x the operation bandwidth of alternative schemes, is a compelling candidate for future...
Dark matter candidates on the mass scale of $\mathcal{O}(10-10^4)\,\mathrm{keV}$ produce $\mathcal{O}(1-10^3)\,\mathrm{meV}$ phonon excitations. Probing these low-mass dark matter candidates requires quantum sensors with meV phonon energy resolution ($\sigma_E$). Transition edge sensors (TESs) have achieved the lowest energy threshold so far, with $\sigma_E \sim...
Searching for light dark matter between 10keV and 100MeV requires noval sub-eV threshold detectors. Superconducting sensors that detects phonons from the crystal substrate is a promising direction. In addition to the mature transition edge sensors (TESs), kinetic inductance devices (KIDs) provide another option, which has the advantage of up-scaling with multiplexed readout.
We work on...
Here, we present the LLNL Cosmic Sandwich, a detector consisting of three cm2-scale sapphire substrates layered in close vertical proximity. The middle section of the Sandwich comprises an array of transmons patterned on the surface, and the top and bottom substrates each have grids of microwave kinetic inductance detectors (MKIDs). This detector package enables tagging of events that are...
Phonon-sensitive Microwave Kinetic Inductance Detectors (MKIDs) are promising superconducting sensor candidates, offering scalability and lower energy resolution for fundamental physics experiments such as low-mass dark matter direct detection and neutrinoless double beta decay searches. Energy resolution of the sensor to phononic signal can be improved by improving phonon collection...
The post-inflationary QCD axion is a sharp BSM theory target that spans a frequency range from 5 to 50 GHz known as the classical window. At these higher frequencies, linear amplifiers as cavity haloscope receivers are severely degraded in sensitivity by the standard quantum limit: $P_\mathrm{bkgd}=h\nu\Delta\nu$. For calorimetric measurements, this limit can be evaded through the use of...
With decades of null results from direct detection experiments for dark matter with mass above ~1 GeV, sub-GeV dark matter has become an increasingly compelling alternative. At such masses, we expect meV-scale nuclear recoil energies, where phonons are the dominant energy excitation. Superconducting charge qubits demonstrate sensitivity to single quasiparticle tunneling events, a property that...
Superconducting qubits offer a promising new platform for detectors as a result of their natural sensitivity to their environment. In recent years superconducting qubits have made huge strides in performance and quality. These devices have already demonstrated exceptional sensitivity for prototype dark matter searches due to their high sensitivity. As qubits achieve higher coherence times, the...
Impacts from high-energy particles have been demonstrated to cause correlated errors in superconducting qubits by increasing the quasiparticle density in the Josephson junction (JJ) leads. These correlated errors are particularly harmful as they cannot be remedied via conventional error correcting codes. It was recently demonstrated that these correlated errors can be reduced or eliminated by...
Superconducting qubit sensors are a compelling option for detecting faint signals from dark matter or low energy neutrino interactions. Improving their reach calls for both signal amplification and background suppression. The Quantum Zeno Effect (QZE)--which governs how entanglement reshapes a quantum system's time evolution--addresses both needs. By quantifying these modified time dynamics,...
The calibration of ultra-sensitive THz/meV detectors in cryogenic environments is a significant challenge, as standard fiber optics absorb THz radiation and tunable sources are limited. A system is being developed using a photomixer and hollow circular waveguides to deliver tunable frequency THz photons to cryogenic sensors. This work is motivated by the need to calibrate superconducting...
The development of quantum-limited charge amplifiers is enabling new classes of detectors for rare-event physics, with applications in low-mass dark matter and CEvNS. We report on recent progress in the development of a cavity-coupled Cooper pair transistor (cCPT) amplifier, designed to achieve sub single-electron sensitivity while remaining modular and detector-target agnostic. Building on...
Kinetic inductance phonon-mediated (KIPM) detectors are superconducting microcalorimeters that show promise in applications toward low-threshold rare-event searches. Despite an excellent sensor energy resolution, the overall energy resolution of KIPM detectors is limited by an observed single-percent phonon collection efficiency. Monte Carlo simulations of charge and phonon processes using the...
Understanding phonon and charge propagation in superconducting devices is essential for low-threshold dark matter and neutrino searches. In this work, we extend G4CMP capabilities to model phonon propagation in novel superconducting materials, including Aluminum, Tantalum, and Niobium. Furthermore, we enable phononโquasiparticle transport in the interface of superconducting thin film and the...
The BeEST experiment searches for physics beyond the standard model (BSM) in the neutrino sector by measuring the recoiling daughter from the electron capture (EC) decay of 7Be. The 7Be is embedded in superconducting tunnel junction (STJ) sensors such that the low-energy (eV-scale) decay products are detected with sub-eV energy resolution. Modelling of low-energy backgrounds in the SiO2/Si...
Superconducting qubits are intrinsically sensitive to environmental fluctuations, making them promising platforms for sub-eV energy sensing. In this regime, qubits can operate as Cooper pair breaking detectors, where incident energy generates phonons in the substrate (eg; Sapphire) that subsequently break Cooper pairs in the qubitโs superconducting film. The resulting quasiparticles tunnel...
When an ionizing particle interacts with the substrate of a superconducting qubit chip, it generates athermal phonons that propagate through the material, breaking Cooper pairs in the superconducting film and inducing quasiparticle poisoning. This process increases correlated error rates, posing a significant challenge for the development of fault-tolerant quantum computing. Additionally, the...
The nature of dark matter is one of the most perplexing open questions in physics today. A particularly compelling dark matter candidate called the QCD axion, if discovered, could simultaneously solve the Strong CP Problem of quantum chromodynamics and account for the missing mass in our universe. The "axion haloscope" is an established detection technique, designed to resonantly convert ยตeV...
QCD axions are doubly motivated due to their ability to comprise dark matter and solve the strong CP problem. This makes them one of the most promising dark matter candidates. Haloscopes are axion detection experiments that use tunable microwave cavities to resonantly enhance signals from the axion-photon coupling that occurs in the presence of a strong magnetic field. Because the haloscope...
The SERAPH (SupERconducting Axion and Paraphoton Haloscope) experiment is a family of superconducting haloscopes being developed by the Superconducting Quantum Materials and Systems (SQMS) Center to search for wavelike dark matter. This presentation will focus on preliminary results from our dark photon dark matter search using a widely-tunable SRF cavity operating between 4-7 GHz, nicknamed...
QUAntum LImited PHotons In the Dark Experiment (QUALIPHIDE) searches for Hidden Photons (HP) as dark matter. Quantum sensing techniques, such as photon counting, enable exploring new phase space for both HPs and axion like particles as candidates for dark matter. We have fielded a deeper than standard quantum limit search with single photon resolving MKIDs. This newest version of QUALIPHIDE...
We propose a magnetic resonance force microscopy (MRFM) search for axion dark matter around $m_a\sim \rm GeV$. The experiment leverages the axion's derivative coupling to electrons, which induces an effective A.C. magnetic field on a sample of electron spins polarized by a D.C. magnetic field and a micromagnet. A second pump field at a nearby frequency enhances the signal, and the detuning is...
Superconducting Nanowire Single Photon Detectors (SNSPDs) are a leading detector technology for single-photon detection with diverse applications, due to their ultra-low energy threshold of below 0.04~eV, low dark counts of 10^-5~Hz, and pico-second level time resolution. Recent advancement in the fabrication of large area superconducting microwire single photon detectors (SMSPDs) make them an...
We propose a new particle detection scheme that utilizes Nitrogen-Vacancy (NV) center magnetometry for probing variations in magnetic field exclusion through a superconductor as it undergoes a phase transition. We present exploratory simulation results of a Superconductor-NV center-based detector to probe the Meissner screening for low-energy event detection. A modular PythonโCOMSOL workflow...
Quantum sensors connected with optical fiber can effectively cover large areas and provide phase coherence between distant experiments by transmitting entangled photons through phase stable links. These sensors have applications in gravitational wave detection and km-long wavelength axion detection. Optical phase stability presents experimental challenges in deployed fibers where vibrations...
We present initial on-sky observation data from superconducting mm-wave filter bank spectrometers on the South Pole Telescope Shirokoff Line Intensity Mapper (SPT-SLIM). The SPT-SLIM experiment is designed to measure redshifted carbon monoxide (CO) line emission from galaxies at 0.5 < z < 2. It was first deployed during the 2024-2025 Antarctic summer for a commissioning and two-week observing...
The SuperCDMS-HVeV (High-Voltage with eV resolution) program is an R&D project focused on developing detectors with low energy resolution to search for low-mass dark matter ( โฒ 1 GeV/c2), study charge-transport in cryogenically-cooled crystals, and probe unclassified backgrounds at low energy. The program utilizes gram-scale silicon detectors instrumented with TES (transition-edge...
