Université de Fribourg

Analysis method for detecting topological defect dark matter with a global magnetometer network

Masia-Roig, Hector ; A.Smiga, Joseph ; Budker, Dmitry ; Dumont, Vincent ; Gruji, Zoran ; Kim, Dongok ; Kimball, Derek F. Jackson ; Lebedev, Victor ; Monroy, Madeline ; Pustelny, Szymon ; Scholtes, Theo ; Segura, Perrin C. ; Semertzidi, Yannis K. ; Shin, Yun Chang ; Stalnaker, Jason E. ; Sulai, Ibrahim ; Weis, Antoine ; Wickenbrock, Arne

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...

Université de Fribourg

Characterization of the global network of optical magnetometers to search for exotic physics (GNOME)

Afach, S. ; Budker, D. ; Camp, G. De ; Dumont, V. ; Grujić, Zoran Dragan ; Guo, H. ; Jackson Kimball, D. F. ; Kornack, T. W. ; Lebedev, Victor ; Li, W. ; Masia-Roig, H. ; Nix, S. ; Padniuk, M. ; Palm, C. A. ; Pankow, C. ; Penaflor, A. ; Peng, X. ; Pustelny, Simon ; Scholtes, Theo ; Smiga, J. A. ; Stalnaker, J. E. ; Weis, Antoine ; Wickenbrock, A. ; Wurm, D.

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...

Université de Fribourg

Searching for axion stars and $Q$-balls with a terrestrial magnetometer network

Kimball, D. F. Jackson ; Budker, D. ; Eby, J. ; Pospelov, M. ; Pustelny, Szymon ; Scholtes, Theo ; Stadnik, Y. V. ; Weis, Antoine ; Wickenbrock, A.

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...

Université de Fribourg

Quantitative study of optical pumping in the presence of spin-exchange relaxation

Shi, Yongqi ; Scholtes, Theo ; Grujić, Zoran D. ; Lebedev, Victor ; Dolgovskiy, Vladimir ; Weis, Antoine

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)...

Université de Fribourg

An optically pumped magnetometer working in the light-shift dispersed Mz mode

Schultze, Volkmar ; Schillig, Bastian ; IJsselsteijn, Rob ; Scholtes, Theo ; Woetzel, Stefan ; Stolz, Ronny

In: Sensors, 2017, vol. 17, no. 3, p. 561

We present an optically pumped magnetometer working in a new operational mode— the light-shift dispersed Mz (LSD-Mz) mode. It is realized combining various features; (1) high power off-resonant optical pumping; (2) Mz configuration, where pumping light and magnetic field of interest are oriented parallel to each other; (3) use of small alkali metal vapor cells of identical properties in...

Université de Fribourg

Orientational dependence of optically detected magnetic resonance signals in laser-driven atomic magnetometers

Colombo, Simone ; Dolgovskiy, Vladimir ; Scholtes, Theo ; Grujić, Zoran D. ; Lebedev, Victor ; Weis, Antoine

In: Applied Physics B, 2017, vol. 123, no. 1, p. 35

We have investigated the dependence of lock-in-demodulated Mx-magnetometer signals on the orientation of the static magnetic field B0 of interest. Magnetic resonance spectra for 2400 discrete orientations of B0 covering a 4π solid angle have been recorded by a PC-controlled steering and data acquisition system. Off-line fits by previously derived lineshape functions allow us to extract the...

Université de Fribourg

Suppression of spin-exchange relaxation in tilted magnetic fields within the geophysical range

Scholtes, Theo ; Pustelny, Szymon ; Fritzsche, Stephan ; Schultze, Volkmar ; Stolz, Ronny ; Meyer, Hans-Georg

In: Physical Review A, 2016, vol. 94, no. 1, p. 13403

We present a detailed experimental and theoretical study on the relaxation of spin coherence due to the spin-exchange mechanism arising in the electronic ground states of alkali-metal vapor atoms. As opposed to the well-explored formation of a stretched state in a longitudinal geometry (magnetic field parallel to the laser propagation direction) we employ adapted hyperfine-selective optical...