8 research outputs found
Recommended from our members
Establishing Privacy Advisory Commissions for the Regulation of Facial Recognition Systems at the Municipal Level
As facial recognition systems (FRS) become widely available, a growing number of local governing bodies across the country have adopted these technologies. Without regulating how and when these technologies are used, the adoption of FRS by municipal governments has the potential to violate civil liberties and disproportionately harm marginalized groups. FRS may be an invaluable tool for law enforcement; however, best practices must be adopted to curb their misuse, specifically at the municipal level. We propose that cities considering procurement of FRS create an independent privacy advisory commission with a clear mandate, guaranteed cooperation from local government, technology expertise, and community stakeholder input
A stress-induced source of phonon bursts and quasiparticle poisoning.
The performance of superconducting qubits is degraded by a poorly characterized set of energy sources breaking the Cooper pairs responsible for superconductivity, creating a condition often called quasiparticle poisoning. Both superconducting qubits and low threshold dark matter calorimeters have observed excess bursts of quasiparticles or phonons that decrease in rate with time. Here, we show that a silicon crystal glued to its holder exhibits a rate of low-energy phonon events that is more than two orders of magnitude larger than in a functionally identical crystal suspended from its holder in a low-stress state. The excess phonon event rate in the glued crystal decreases with time since cooldown, consistent with a source of phonon bursts which contributes to quasiparticle poisoning in quantum circuits and the low-energy events observed in cryogenic calorimeters. We argue that relaxation of thermally induced stress between the glue and crystal is the source of these events
A Stress Induced Source of Phonon Bursts and Quasiparticle Poisoning
The performance of superconducting qubits is degraded by a poorly
characterized set of energy sources breaking the Cooper pairs responsible for
superconductivity, creating a condition often called "quasiparticle poisoning."
Recently, a superconductor with one of the lowest average quasiparticle
densities ever measured exhibited quasiparticles primarily produced in bursts
which decreased in rate with time after cooldown. Similarly, several cryogenic
calorimeters used to search for dark matter have also observed an unknown
source of low-energy phonon bursts that decrease in rate with time after
cooldown. Here, we show that a silicon crystal glued to its holder exhibits a
rate of low-energy phonon events that is more than two orders of magnitude
larger than in a functionally identical crystal suspended from its holder in a
low-stress state. The excess phonon event rate in the glued crystal decreases
with time since cooldown, consistent with a source of phonon bursts which
contributes to quasiparticle poisoning in quantum circuits and the low-energy
events observed in cryogenic calorimeters. We argue that relaxation of
thermally induced stress between the glue and crystal is the source of these
events, and conclude that stress relaxation contributes to quasiparticle
poisoning in superconducting qubits and the athermal phonon background in a
broad class of rare-event searches.Comment: 13 pages, 6 figures. W. A. Page and R. K. Romani contributed equally
to this work. Correspondence should be addressed to R. K. Roman
Discrimination in Liquid Xenon and Calorimetry in Superfluid Helium for the Direct Detection of Particle Dark Matter
In this dissertation, we present several recent developments in instrumentation for dark matter detectors. The liquid/gas two-phase xenon time projection chamber is well-established as an excellent technology to search for Weakly Interacting Massive Particles (WIMPs). We present analyses of data from the Large Underground Xenon (LUX) and Particle Identification in Xenon at Yale (PIXeY) experiments, in which we study signal vs. background discrimination as a function of detector parameters. This informs design decisions for current and future xenon detectors. Then, we focus on cutting-edge calorimetric technologies geared towards searches at the MeV/c^2 scale. We present measurements of the superconducting transition of several materials, and we discuss their potential use as transition-edge sensors (TES). Helium as a detection target with TES signal readout is explored, and its sensitivity to dark matter-induced nuclear recoils is calculated
Recommended from our members
Streamlining USDA Regulation of Gene Editing to Benefit US Agriculture
Feeding a growing world population and adapting agricultural production to a changing climate is a significant challenge that can be mitigated through the use of new gene-editing technologies in crops. However, current regulatory processes are overly burdensome and confusing, have limited scientific innovation, and prevent the widespread production of genetically engineered (GE) crops. To address this, we propose the regulatory exemption of GE plants that have a previously-reviewed trait and mechanism of action, a unified and detailed web platform for applications for commercial approval, and the consolidation of federal regulatory communication to the USDA
Recommended from our members
California Lawmakers Should Take Action to Mitigate the Effects of the 2019 PG&E Bankruptcy
In early 2019, the Pacific Gas and Electric Company (PG&E), California’s largest utility, filed for bankruptcy in anticipation of being held liable for the 2018 Camp Fire, the most deadly wildfire in California history. While PG&E is an investor-owned utility (IOU), it serves 5.2 million households across the northern two-thirds of California and plays a critical role in the state’s energy generation, distribution and long-term goals. As the bankruptcy unfolds and California lawmakers decide how to weigh in on these proceedings, we highlight several key topics for consideration: renewable energy, energy access, and wildfire liability. Regardless of the outcome of PG&E’s bankruptcy, it is in California’s best interest for lawmakers to establish a robust wildfire fund, coordinate energy purchasing and distribution among new local energy providers, and scale up the development of local energy storage
Recommended from our members
Streamlining USDA Regulation of Gene Editing to Benefit US Agriculture
Feeding a growing world population and adapting agricultural production to a changing climate is a significant challenge that can be mitigated through the use of new gene-editing technologies in crops. However, current regulatory processes are overly burdensome and confusing, have limited scientific innovation, and prevent the widespread production of genetically engineered (GE) crops. To address this, we propose the regulatory exemption of GE plants that have a previously-reviewed trait and mechanism of action, a unified and detailed web platform for applications for commercial approval, and the consolidation of federal regulatory communication to the USDA
Recommended from our members
A Stress Induced Source of Phonon Bursts and Quasiparticle Poisoning
The performance of superconducting qubits is degraded by a poorly
characterized set of energy sources breaking the Cooper pairs responsible for
superconductivity, creating a condition often called "quasiparticle poisoning."
Recently, a superconductor with one of the lowest average quasiparticle
densities ever measured exhibited quasiparticles primarily produced in bursts
which decreased in rate with time after cooldown. Similarly, several cryogenic
calorimeters used to search for dark matter have also observed an unknown
source of low-energy phonon bursts that decrease in rate with time after
cooldown. Here, we show that a silicon crystal glued to its holder exhibits a
rate of low-energy phonon events that is more than two orders of magnitude
larger than in a functionally identical crystal suspended from its holder in a
low-stress state. The excess phonon event rate in the glued crystal decreases
with time since cooldown, consistent with a source of phonon bursts which
contributes to quasiparticle poisoning in quantum circuits and the low-energy
events observed in cryogenic calorimeters. We argue that relaxation of
thermally induced stress between the glue and crystal is the source of these
events, and conclude that stress relaxation contributes to quasiparticle
poisoning in superconducting qubits and the athermal phonon background in a
broad class of rare-event searches