A5050180656- Atomic and Subatomic Physics Research
- Experimental and Theoretical Physics Studies
- Magnetic Field Sensors Techniques
- Magnetic Properties and Applications
- Advanced MEMS and NEMS Technologies
- Characterization and Applications of Magnetic Nanoparticles
- Mechanical and Optical Resonators
- Ferroelectric and Piezoelectric Materials
- Noncommutative and Quantum Gravity Theories
- Geophysics and Sensor Technology
- Quantum Electrodynamics and Casimir Effect
- Relativity and Gravitational Theory
- Quantum, superfluid, helium dynamics
- Domain Adaptation and Few-Shot Learning
- Advanced NMR Techniques and Applications
- Quantum optics and atomic interactions
- Stochastic Gradient Optimization Techniques
- Geophysics and Gravity Measurements
- Electronic and Structural Properties of Oxides
- Acoustic Wave Resonator Technologies
- Physics of Superconductivity and Magnetism
- Electrostatics and Colloid Interactions
- Machine Learning and Algorithms
- Scientific Computing and Data Management
- Magnetic and transport properties of perovskites and related materials
Form Energy (United States)
2021-2024
Stanford University
2003-2021
Palo Alto Research Center
2015-2017
Princeton University
2007-2011
Brown University
1999
Yale University
1999
We develop a new comagnetometer using $^{21}$Ne atoms with nuclear spin $I=3/2$ and Rb polarized by spin-exchange K to search for tensor interactions that violate local Lorentz invariance. frequently reverse orientation of the experiment signals at first second harmonics sidereal frequency. constrain 4 5 spatial Lorentz-violating coefficients $c^n_{jk}$ parameterize anisotropy maximum attainable velocity neutron level $10^{-29}$, improving previous limits 2 orders magnitude placing most...
We performed a search for neutron spin coupling to Lorentz- and CPT-violating background field using magnetometer with overlapping ensembles of K ³He atoms. The comagnetometer is mounted on rotary platform frequent reversal its orientation. measure sidereal oscillations in the signal anomalous extra-solar origin. determine equatorial components interacting be b˜Xn=(0.1 ± 1.6) × 10⁻³³ GeV b˜Yn=(2.5 GeV, improving previous limit by factor 30. This measurement represents highest energy...
We have searched for large deviations from Newtonian gravity by means of a finite-frequency microcantilever-based experiment. Our data eliminate consideration mechanisms deviation that posit strengths approximately 10(4) times at length scales 20 microm. This measurement is 3 orders magnitude more sensitive than others provide constraints similar scales.
Several recent theories suggest that light moduli or particles in ``large'' extra dimensions could mediate macroscopic forces exceeding gravitational strength at length scales below a millimeter. Such new can be parameterized as Yukawa-type correction to the Newtonian potential of $\ensuremath{\alpha}$ relative gravity and range $\ensuremath{\lambda}$. To extend search for such physics we have improved our apparatus utilizing cryogenic micro-cantilevers capable measuring attonewton forces,...
Recent theories of physics beyond the standard model have predicted deviations from Newtonian gravity at short distances. In order to test these theories, we a built an apparatus that can measure attonewton-scale forces between gold masses separated by distances on $25\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. A micromachined silicon cantilever was used as force sensor, and its displacement measured with fiber interferometer. We our measurements set bounds magnitude $\ensuremath{\alpha}$...
We present an experimental and theoretical study of a scalar atomic magnetometer using oscillating field-driven Zeeman resonance in high-density optically-pumped potassium vapor. describe implementation gradiometer with noise level below 10 fT/Hz^{1/2}, fractional field sensitivity 10^{-9}/Hz^{1/2}, active measurement volume about 1.5 cm^3. show that the fundamental is determined by rate alkali-metal spin-exchange collisions even though linewidth can be made much smaller than pumping most...
Ferrite materials provide magnetic shielding performance similar to commonly used high permeability metals but have lower intrinsic noise generated by thermal Johnson currents due their electrical resistivity. Measurements inside a ferrite shield with spin-exchange relaxation-free atomic magnetometer reveal level of 0.75fTHz−1∕2, 25 times than what would be expected in comparable μ-metal shield. The authors identify 1∕f component the magnetization fluctuations and derive general...
A heat-switch-based electrocaloric cooler is reported in this letter. The device consists of two silicon heat switches and an module based on BaTO3 multilayer capacitors (MLCs). To operate the cooler, are actuated synchronously with application electric fields across MLCs. Heat flux versus temperature lift fully characterized. With field strength 277 kV/cm, system achieves a maximum 36 mW greater than 0.3 °C, close to expected MLC adiabatic change 0.5 °C. shown work reliably over thousands...
Though data augmentation has become a standard component of deep neural network training, the underlying mechanism behind effectiveness these techniques remains poorly understood. In practice, policies are often chosen using heuristics either distribution shift or diversity. Inspired by these, we seek to quantify how improves model generalization. To this end, introduce interpretable and easy-to-compute measures: Affinity Diversity. We find that performance is predicted not alone but jointly...
Realization of the potential electrocaloric heat pumps includes consideration not only material properties but also device characteristics and cycle operation. We present detailed models analysis that elucidate key parameters for performance optimization. show temperature lift, cooling power, efficiency a system driven by switches depend on operating conditions combined thermal both capacitor. experimental results validate draw conclusions about building high-performance systems.
This paper presents two versions of a silicon mechanical heat switch designed for electrocaloric cooling. The first design, which consists 10-mm-by-12.8-mm micromachined parts, allows investigation the performance reciprocating solid thermal shunt device. has measured contrast ratio in range 34-59. second design adds self-alignment features that constrain motion to facilitate fabrication and integration. self-aligned >28. It been successfully operated >18 000 cycles employed an cooler....
Recent theories of physics beyond the standard model have predicted deviations from Newtonian gravity at short distances. In order to test these theories, we a built an apparatus that can measure attonewton-scale forces between gold masses separated by distances on 25 microns. A micromachined silicon cantilever was used as force sensor, and its displacement measured with fiber interferometer. We our measurements set bounds magnitude alpha length scale lambda Yukawa-type gravity; results...
Abstract Fe anodes are emerging as cost‐effective components in long duration storage applications, with a benefit being the high natural abundance of Fe. Additive and electrode design have advanced performance electrodes, but more precise understanding formation process failure mechanisms is important for continued optimization. These interfacial electrochemical processes, which involve short‐lived intermediate species, require analysis spatial temporal resolution to provide full picture....
Forests of the Earth are a vital carbon sink while providing an essential habitat for biodiversity. Vegetation productivity (VP) is critical indicator uptake in atmosphere. The leaf area index crucial vegetation used VP estimation. This work proposes to predict (LAI) using climate variables better understand future dynamics; our approach leverages capacities V-Net architecture spatiotemporal LAI prediction. Preliminary results well-aligned with established quality standards products...
We report experimental tests of the present models peak effect in weakly disordered type-II superconductors. Our results favour scenario which arises from a crossover between Larkin pinning length and rapidly falling elastic vortex phase populated with thermally excited topological defects. A thickness dependence study onset at varying driving currents suggests that both screw edge dislocations are involved lattice disordering. The driven dynamics threedimensional samples drastically...