Michael Romalis
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View article: A $^{3}$He-$^{21}$Ne Ramsey Comagnetometer with sub-nHz frequency resolution
A $^{3}$He-$^{21}$Ne Ramsey Comagnetometer with sub-nHz frequency resolution Open
Nuclear spin comagnetometers offer exceptional precision in measurements of spin energy levels and exhibit long-term stability, making them powerful tools for probing spin-dependent physics beyond the Standard Model as well as for inertial…
Pulsed vector atomic magnetometer using an alternating fast-rotating field Open
We introduce a vector atomic magnetometer that employs a fast-rotating magnetic field applied to a pulsed 87 Rb scalar atomic magnetometer. This approach enables simultaneous measurements of the total magnetic field and its two polar angle…
Pulsed Dual-axis Alkali-metal-noble-gas Comagnetometer Open
Alkali-metal-noble-gas comagnetometers are precision probes well-suited for tests of fundamental physics and inertial rotation sensing, combining high sensitivity of the spin-exchange-relaxation free (SERF) magnetometers with inherent supp…
Long spin-1/2 noble gas coherence times in mm-sized anodically bonded batch-fabricated $^{3}$He-$^{129}$Xe-$^{87}$Rb cells Open
As the only stable spin-1/2 noble gas isotopes, $^{3}$He and $^{129}$Xe are promising systems for inertial rotation sensing and searches for exotic spin couplings. Spin-1/2 noble gases have intrinsic coherence times on the order of hours t…
Vapor cell Rydberg atom electrometry with time-separated fields Open
Rydberg atoms have large transition electric dipole moments and high sensitivity to electric fields. We describe a new method for microwave field sensing in a vapor cell consisting of separate excitation, quantum evolution between two Rydb…
Large-scale, Multi-pass, Two-chamber RF Atomic Magnetometer Open
We describe one of the largest radio-frequency RF atomic magnetometers presently operating. A total atomic volume of 128 $\mathrm{cm^3}$, with correspondingly large number of $^{87}$Rb atoms, can reduce atom noise. A total of 44 passes of …
Pulsed Vector Atomic Magnetometer Using an Alternating Fast-Rotating Field Open
We introduce a vector atomic magnetometer that employs a fast-rotating magnetic field applied to a pulsed $^{87}$Rb scalar atomic magnetometer. This approach enables simultaneous measurements of the total magnetic field and its two polar a…
Laboratory Constraints on the Neutron-Spin Coupling of feV-Scale Axions Open
Ultralight axion-like particles can contribute to the dark matter near the Sun, leading to a distinct, stochastic signature in terrestrial experiments. We search for such particles through their neutron-spin coupling by re-analyzing approx…
Laboratory Constraints on the Neutron-Spin Coupling of feV-scale Axions Open
Ultralight axion-like particles can contribute to the dark matter near the Sun, leading to a distinct, stochastic signature in terrestrial experiments. We search for such particles through their neutron-spin coupling by re-analyzing approx…
View article: Femtotesla Nearly-Quantum-Noise-Limited Pulsed Gradiometer at Earth-Scale Fields
Femtotesla Nearly-Quantum-Noise-Limited Pulsed Gradiometer at Earth-Scale Fields Open
We describe a finite fields magnetic gradiometer using an intense pulsed\nlaser to polarize a $^{87}$Rb atomic ensemble and a compact VCSEL probe laser\nto detect paramagnetic Faraday rotation in a single multipass cell. We report\ndiffere…
Comagnetometer probes of dark matter and new physics Open
We discuss the use of comagnetometry in studying new physics that couples to fermionic spin. Modern comagnetometry is -- in absolute energy units -- the most sensitive experimental technique for measuring the energy difference between quan…
View article: Heading errors in all-optical alkali-metal-vapor magnetometers in geomagnetic fields
Heading errors in all-optical alkali-metal-vapor magnetometers in geomagnetic fields Open
Alkali-metal atomic magnetometers suffer from heading errors in geomagnetic\nfields as the measured magnetic field depends on the orientation of the sensor\nwith respect to the field. In addition to the nonlinear Zeeman splitting, the\ndif…
New Limits on Anomalous Spin-Spin Interactions Open
We report the results of a new search for long-range spin-dependent interactions using a Rb-^{21}Ne atomic comagnetometer and a rotatable electron spin source based on a SmCo_{5} magnet with an iron flux return. By looking for signal corre…
View article: Total-field atomic gradiometer for unshielded portable magnetoencephalography
Total-field atomic gradiometer for unshielded portable magnetoencephalography Open
Recording of magnetic fields generated by neuronal electrical currents is one of a few available methods for non-invasive functional brain imaging. The fields generated by such currents are about 100 million times smaller than Earth's magn…
Calculation of scalar nuclear spin-spin coupling in a noble-gas mixture Open
Indirect spin-spin interactions between nuclei bound in a molecule are well-known in nuclear magnetic resonance, but such interactions between unbound atoms are less well studied and are often assumed to be zero. We present the first preci…
Improved Limits on Spin-Mass Interactions Open
Very light particles with CP-violating couplings to ordinary matter, such as axions or axionlike particles, can mediate long-range forces between polarized and unpolarized fermions. We describe a new experimental search for such forces bet…
View article: Correlation function of spin noise due to atomic diffusion
Correlation function of spin noise due to atomic diffusion Open
We use paramagnetic Faraday rotation to study spin noise spectrum from unpolarized Rb vapor in a tightly focused probe beam in the presence of N2 buffer gas. We derive an analytical form for the diffusion component of the spin noise time-c…
View article: Effects of the Lorentz Invariance Violation on Coulomb Interactions in Nuclei and Atoms
Effects of the Lorentz Invariance Violation on Coulomb Interactions in Nuclei and Atoms Open
Anisotropy in the speed of light that has been constrained by Michelson-Morley-type experiments also generates anisotropy in the Coulomb interactions. This anisotropy can manifest itself as an energy anisotropy in nuclear and atomic experi…