A5069405212- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Particle physics theoretical and experimental studies
- Photonic and Optical Devices
- Computational Physics and Python Applications
- Quantum Information and Cryptography
- Cold Atom Physics and Bose-Einstein Condensates
- Particle Detector Development and Performance
- Cosmology and Gravitation Theories
- Semiconductor Quantum Structures and Devices
- Scientific Research and Discoveries
- Spectroscopy and Laser Applications
- Advanced Frequency and Time Standards
- Meteorological Phenomena and Simulations
- Advanced NMR Techniques and Applications
- Sensor Technology and Measurement Systems
- Quantum, superfluid, helium dynamics
- Theoretical and Computational Physics
- Magnetic Field Sensors Techniques
- Magnetic properties of thin films
- Semiconductor Lasers and Optical Devices
- Advancements in Semiconductor Devices and Circuit Design
- Scientific Measurement and Uncertainty Evaluation
Lawrence Livermore National Laboratory
2022-2024
University of California, Berkeley
2012-2021
This Letter reports the results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 μeV. The excludes range of axion-photon couplings predicted by plausible models invisible axion. unprecedented sensitivity is achieved operating large-volume at subkelvin temperatures, thereby reducing thermal noise as well excess ultralow-noise superconducting quantum interference device amplifier used signal power readout. Ongoing searches will provide nearly definitive tests...
This Letter reports on a cavity haloscope search for dark matter axions in the Galactic halo mass range 2.81-3.31 μeV. utilizes combination of low-noise Josephson parametric amplifier and large-cavity to achieve unprecedented sensitivity across this range. excludes full axion-photon coupling values predicted benchmark models invisible axion that solve strong CP problem quantum chromodynamics.
The μeV axion is a well-motivated extension to the standard model. Axion Dark Matter eXperiment (ADMX) collaboration seeks discover this particle by looking for resonant conversion of dark-matter axions microwave photons in strong magnetic field. In Letter, we report results from pathfinder experiment, ADMX "Sidecar," which designed pave way future, higher mass, searches. This testbed experiment lives inside and operates tandem with main experiment. Sidecar excludes masses three widely...
Searching for axion dark matter, the ADMX Collaboration acquired data from January to October 2018, over mass range 2.81–3.31 μeV, corresponding frequency 680–790 MHz. Using an haloscope consisting of a microwave cavity in strong magnetic field, experiment excluded Dine-Fischler-Srednicki-Zhitnisky (DFSZ) axions at 90% confidence level and 100% matter density this entire range, except few gaps due mode crossings. This paper explains full analysis run 1B, motivating choices informed by...
The spectral density ${S}_{\ensuremath{\Phi}}(f)={A}^{2}/(f/1\text{ }\text{ }\mathrm{Hz}{)}^{\ensuremath{\alpha}}$ of magnetic flux noise in ten dc superconducting quantum interference devices (SQUIDs) with systematically varied geometries shows that $\ensuremath{\alpha}$ increases as the temperature is lowered; so doing, each spectrum pivots about a nearly constant frequency. mean-square noise, inferred by integrating power spectra, grows rapidly and at given approximately independent outer...
Axion dark matter experiment ultra-low noise haloscope technology has enabled the successful completion of two science runs (1A and 1B) that looked for axions in 2.66-3.1 μeV mass range with Dine-Fischler-Srednicki-Zhitnisky sensitivity [Du et al., Phys. Rev. Lett. 120, 151301 (2018) Braine 124, 101303 (2020)]. Therefore, it is most sensitive axion search to date this range. We discuss technological advances made last several years achieve sensitivity, which includes implementation...
According to recent predictions, a microscale ferromagnetic needle will precess under the influence of small applied torque, if sufficiently isolated from environment. In fact, such system could be used measure torques with sensitivity far surpassing standard quantum limit for free ensemble spins. To observe precession and carry out ultrasensitive torque measurements, requires nearly frictionless suspension. Here crucial initial steps are realized by levitating micrometer-scale particle...
The underlying charge noise mechanisms found in tantalum are experimentally investigated, providing a wealth of information on the technological possibilities superconducting qubits based this material.
For many types of superconducting qubits, magnetic flux noise is a source pure dephasing. Measurements on representative dc quantum interference device (SQUID) over range temperatures show that $S_\Phi(f) = A^2/(f/1 \hbox{Hz})^\alpha$, where $S_\Phi$ the spectral density, $A$ order 1 $\mu\Phi_0 \, \hbox{Hz}^{-1/2}$ and $0.61 \leq \alpha 0.95$; $\Phi_{0}$ quantum. qubit with an energy level splitting linearly coupled to applied flux, calculations dependence dephasing time $\tau_\phi$ Ramsey...
The ADMX Collaboration gathered data for its Run 1A axion dark matter search from January 2017 to June 2017, scanning with an haloscope over the frequency range 645–680 MHz (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>2.66</a:mn><a:mi>–</a:mi><a:mn>2.81</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi mathvariant="normal">μ</a:mi><a:mi>eV</a:mi></a:mrow></a:math> in mass) at Dine-Fischler-Srednicki-Zhitnitskii (DFSZ) sensitivity. resulting found no...
Building usefully coherent superconducting quantum processors depends on reducing losses in their constituent materials [I. Siddiqi, Nat. Rev. Mater. 6, 875–891 (2021)]. Tantalum, like niobium, has proven utility as the primary layer within highly qubits [Place et al., Commun. 12(1), 1–6 (2021) and Wang npj Quantum Inf. 8(1), (2022)]. However, unlike Nb, high temperatures are typically used to stabilize desirable body-centered-cubic phase, α-Ta, during thin film deposition. It long been...
We demonstrate a spurious contribution to low-frequency critical current noise in Josephson junctions—normally attributed charge trapping the barrier—arising from temperature instabilities inherent cryogenic systems. These fluctuations modify via its dependence. Cross-correlations between measured and Al-AlOx-Al junctions show that, despite excellent stability, induce observable fluctuations. Particularly, because 1/f has decreased with improved fabrication techniques recent years, it is...
The performance of SQUIDs and superconducting qubits based on magnetic flux is degraded by the presence noise with a spectral density scaling approximately inversely frequency. It generally accepted that arises from random reversal spins surface superconductors. We introduce numerical method calculating mean square independently fluctuating thin-film loops arbitrary geometry. By reciprocity, proportional to 〈B(r)2〉, where B(r) field generated circulating current around loop r varies over...
Abstract Building usefully coherent superconducting quantum processors depends on reducing losses in their constituent materials. 1 Tantalum, like niobium, has proven utility as the primary layer within highly qubits. 2,3 But, unlike Nb, high temperatures are typically used to stabilize desirable body-centered-cubic phase, α-Ta, during thin film deposition. It long been known that a Nb permits room-temperature nucleation of 4-6 although neither an epitaxial process nor few-photon microwave...
Transmon qubits fabricated with tantalum metal have been shown to possess energy relaxation times greater than 300 $\mu$s and, as such, present an attractive platform for high precision, correlated noise studies across multiple higher transitions. Tracking the multi-level fluctuating qudit frequencies a precision enabled by coherence of device allows us extract charge offset and quasi-particle dynamics. We observe qualitatively different behavior in those measured previous low frequency...
Building usefully coherent superconducting quantum processors depends on reducing losses in their constituent materials. Tantalum, like niobium, has proven utility as the primary layer within highly qubits. But, unlike Nb, high temperatures are typically used to stabilize desirable body-centered-cubic phase, alpha-Ta, during thin film deposition. It long been known that a Nb permits room-temperature nucleation of although neither an epitaxial process nor few-photon microwave loss...