In: The European Physical Journal D, 2015, vol. 69, no. 11, p. 1-11
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In: The European Physical Journal D, 2015, vol. 69, no. 5, p. 1-10
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In: The European Physical Journal D, 2015, vol. 69, no. 8, p. 1-12
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In: Physics of the Dark Universe, 2020, vol. 28, p. 100494
The Global Network of Optical Magnetometers for Exotic physics searches (GNOME) is a network of time-synchronized, geographically separated, optically pumped atomic magnetometers that is being used to search for correlated transient signals heralding exotic physics. GNOME is sensitive to exotic couplings of atomic spins to certain classes of dark matter candidates, such as axions. This work...
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In: IEEE Transactions on Medical Imaging, 2020, vol. 39, no. 4, p. 922–933
We introduce a Magnetic Particle Imaging Susceptometer (MPIS) that uses a high- sensitivity atomic magnetometer (AM) for recording the spatial distribution of fluid- suspended magnetic nanoparticles. We have evaluated the MPIS performance by one-dimensional scans of structured nanoparticle phantoms, demonstrating, in particular, resolutions of ≈2.5 mm prior to deconvolution and ≪1 mm after ...
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In: Physics of the Dark Universe, 2018, vol. 22, p. 162–180
The Global Network of Optical Magnetometers to search for Exotic physics (GNOME) is a network of geographically separated, time-synchronized, optically pumped atomic magnetometers that is being used to search for correlated transient signals heralding exotic physics. The GNOME is sensitive to nuclear- and electron-spin couplings to exotic fields from astrophysical sources such as compact...
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In: The European Physical Journal D, 2018, vol. 72, no. 4, p. 73
We demonstrate optical pumping on the four hyperfine components of the Cs D1 transition by unpolarized (UPL) resonant laser light. The evidence is based on the reduction of the absorption coefficients κ0 with increasing light power P in an uncoated Cs vapor cell with isotropic spin relaxation. For comparison we perform the same quantitative κ0(P) measurements with linearly-polarized light...
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In: Physical Review D, 2018, vol. 97, no. 4, p. 043002
Light (pseudo-)scalar fields are promising candidates to be the dark matter in the Universe. Under certain initial conditions in the early Universe and/or with certain types of self-interactions, they can form compact dark-matter objects such as axion stars or Q-balls. Direct encounters with such objects can be searched for by using a global network of atomic magnetometers. It is shown that...
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In: Review of Scientific Instruments, 2018, vol. 89, no. 2, p. 025114
We describe the design, applications, and performance of a simple light power controller. The device is built on a fiber-coupled electro-optic modulator with an active electronic feedback. It can be used to actively stabilize laser power or to impress an arbitrary waveform onto the power. The bandwidth of the device is ∼70 kHz.
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In: Physical Review A, 2018, vol. 97, no. 1, p. 013419
We have performed quantitative measurements of the variation of the on-resonance absorption coefficients κ0 of the four hyperfine components of the Cs D1 transition as a function of laser power P, for pumping with linearly and with circularly polarized light. Sublevel populations derived from rate equations assuming isotropic population relaxation (at a rate γ1) yield algebraic κ0(P)...
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