A5012055843- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Magnetic Field Sensors Techniques
- Advanced MRI Techniques and Applications
- Quantum optics and atomic interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced NMR Techniques and Applications
- Advanced Frequency and Time Standards
- Magnetic confinement fusion research
- Geophysics and Gravity Measurements
- Dark Matter and Cosmic Phenomena
- Geophysics and Sensor Technology
- Geomagnetism and Paleomagnetism Studies
- Magnetic Properties and Applications
- Solar and Space Plasma Dynamics
- Characterization and Applications of Magnetic Nanoparticles
- Oceanographic and Atmospheric Processes
- Ionosphere and magnetosphere dynamics
- Magnetic and transport properties of perovskites and related materials
- Earthquake Detection and Analysis
- Spectroscopy and Laser Applications
- Nuclear Physics and Applications
- Physics of Superconductivity and Magnetism
- Cardiac electrophysiology and arrhythmias
- Noncommutative and Quantum Gravity Theories
Twinleaf (United States)
2016-2025
George Mason University
2024
Princeton University
2002-2010
Princeton Plasma Physics Laboratory
2003
Swarthmore College
1998
Alkali-metal magnetometers compete with SQUID detectors as the most sensitive magnetic field sensors. Their sensitivity is limited by relaxation due to spin-exchange collisions. We demonstrate a K magnetometer in which completely eliminated operating at high density and low field. Direct measurements of signal-to-noise ratio give $10\text{ }\mathrm{f}\mathrm{T}\text{ }\mathrm{H}{\mathrm{z}}^{\mathrm{\ensuremath{-}}\mathrm{1}\mathrm{/}\mathrm{2}}$, noise produced Johnson currents shields....
We describe a nuclear spin gyroscope based on an alkali-metal-noble-gas comagnetometer. Optically pumped alkali-metal vapor is used to polarize the noble-gas atoms and detect their gyroscopic precession. Spin precession due magnetic fields as well gradients transients can be cancelled in this arrangement. The sensitivity enhanced by using high-density spin-exchange relaxation free regime. With K-3He comagnetometer we demonstrate rotation of 5 x 10(-7) rad s(-1) Hz(-1/2), equivalent field 2.5...
A magnetometer using spin-polarized K and $^3$He atoms occupying the same volume is used to search for anomalous nuclear spin-dependent forces generated by a separate spin source. We measure changes in precession frequency with resolution of 18 pHz constrain between neutrons be less than $2 \times 10^{-8}$ their magnetic or $2\times 10^{-3}$ gravitational interactions on length scale 50 cm. present new limits neutron coupling light pseudoscalar vector particles, including torsion,...
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 describe linear and nonlinear dynamics of spin-polarized K 3He ensembles interacting by spin exchange. The interactions are dominated the imaginary part spin-exchange cross section each species is primarily affected average magnetization other. Operating in a very low magnetic field we demonstrate novel when electron nuclear precession frequencies nearly matched. observe transverse damping as well dynamic instability spins with polarized vapor. also operation self-compensating...
Abstract Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the of topological defects that could concentrate matter density into many distinct, compact spatial regions small compared with Galaxy but much larger than Earth. Here we report results search transient signals from domain walls by using global network optical magnetometers exotic (GNOME) physics searches. We data, consisting correlated...
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...
The authors report a striking advance in measuring tiny magnetic fields under ambient conditions, using atom--light-interaction techniques enabled by cutting-edge technology. A prototype sensor detects the generated human brain or heart, field-deployable system that works with great sensitivity, unshielded Earth's own field. This technology is scalable to arrays and can be made low-cost, which opens pathways wide variety of applications, such as field triage, brain-machine interfaces, navigation.
We describe a finite fields magnetic gradiometer using an intense pulsed laser to polarize $^{87}$Rb atomic ensemble and compact VCSEL probe detect paramagnetic Faraday rotation in single multipass cell. report differential sensitivity of $14$ fT/Hz$^{1/2}$ over broad dynamic range including Earth's field magnitude common-mode rejection ratio higher than $10^4$. also observe nearly quantum-noise-limited behaviour the gradiometer, by comparing experimental standard deviation estimated...
Abstract We introduce a vector atomic magnetometer that employs fast-rotating magnetic field applied to pulsed 87 Rb scalar magnetometer. This approach enables simultaneous measurements of the total and its two polar angles relative rotation plane. Operating in gradiometer mode, achieves gradient sensitivity 35 $${{{\rm{fT}}}}/\sqrt{{{{\rm{Hz}}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>fT</mml:mi> <mml:mo>/</mml:mo> <mml:msqrt> <mml:mrow> <mml:mi>Hz</mml:mi>...
Whether in medical or security applications, magnetic resonance spectroscopy is very useful for detecting faint signals from target compounds. However, interference (from $e.g.$ a local radio station) can be problem. The authors devise optical atomic-gas detectors that work unshielded environments, and without cryogenic cooling---important advantages real-world use. These sensitive, compact systems offer baseline noise at the quantum limit.
The authors present several methods for heading error suppression in all-optical alkali-vapor magnetometers geomagnetic field ranges. These improvements could result more precise measurements of Earth's magnetic and the development compact miniaturized sensors.
Self-compensated comagnetometers, employing overlapping samples of spin-polarized alkali and noble gases (for example K-${}^{3}\mathrm{He}$) are promising sensors for exotic beyond-the-standard-model fields high-precision metrology such as rotation sensing. When the comagnetometer operates in so-called self-compensated regime, effective field, originating from contact interactions between valence electrons noble-gas nuclei, is compensated with an applied magnetic field. begins operation a...
Magnetic nanoparticles (MNP) offer a large variety of promising applications in medicine thanks to their exciting physical properties, e.g., magnetic hyperthermia and drug targeting. For these applications, it is crucial quantify the amount MNP specific binding state. This information can be obtained by means magnetorelaxometry (MRX), where relaxation previously aligned moments measured. Current MRX with optically pumped magnetometers (OPM) limited OPM recovery time after shut-off external...
Formation and equilibrium studies have been performed on the Swarthmore Spheromak Experiment (SSX). Spheromaks are formed with a magnetized coaxial plasma gun is established in both small (dsmall=0.16 m) large (dlarge=3dsmall=0.50 copper flux conservers. Using magnetic probe arrays it has verified that spheromak formation governed solely by physics (in particular ratio of current to flux, μ0Igun/Φgun) independent conserver dimensions. It also well described force free condition ∇×B=λB...
The Global Network of Optical Magnetometers to search for Exotic physics (GNOME) is a network geographically separated, time-synchronized, optically pumped atomic magnetometers that being used correlated transient signals heralding exotic physics. GNOME sensitive nuclear- and electron-spin couplings fields from astrophysical sources such as compact dark-matter objects (for example, axion stars domain walls). Properties the sensors sensitivity, bandwidth, noise characteristics are studied in...
We present a system for simultaneous recording of the electrocardiogram and magnetocardiogram. The measurement contained printed carbon electrodes SERF magnetometer. use this confirms that position end magnetic T wave extends further than electric wave, which is an important indicator diagnosis cardiological patients drug arrhythmogenicity. analyze phenomenon in depth, demonstrate, it originates from fundamental difference between measurements. measured value always bipolar since...
This paper presents results from the integration of a compact quantum magnetometer system and an agile underwater glider for magnetic survey. A highly maneuverable glider, ROUGHIE, was customized to carry increased payload reduce vehicle’s signature. sensor suite composed vector scalar mounted in external boom at rear vehicle. The combined deployed constrained pool environment detect seeded targets create map test area. Presented is systematic disturbance reduction process, procedure anomaly...
Correlations between magnetic reconnection and energetic ion flow events have been measured with merging force free spheromaks at the Swarthmore Spheromak Experiment. The layer is a linear probe array directly retarding grid energy analyzer. Flow has both in plane of out plane. most occur immediately after formation as dynamically merge. outflow velocity nearly Alfv\'enic. As form equilibria decay, substantially reduced.
We describe a $^{3}$He-$^{129}$Xe comagnetometer operating in stemless anodically bonded cells with 6 mm$^3$ volume and $^{129}$Xe spin coherence time of 300 sec. use $^{87}$Rb pulse-train magnetometer co-linear pump probe beams to study the nuclear frequency shifts caused by polarization $^{3}$He. By systematically varying cell geometry batch fabrication process we can separately measure shape dependent independent shifts. find that certain aspect ratio cylindrical cancel effects $^3$He...
Abstract Results are reported from the first full-scale search for transient signals exotic fields of astrophysical origin using data a newly constructed Earth-scale detector: Global Network Optical Magnetometers Exotic physics searches (GNOME). Data collected by GNOME consist correlated measurements optical atomic magnetometers located in laboratories all over world. searched patterns propagating through network consistent with composed ultralight bosons such as axion-like particles (ALPs)....