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Université de Fribourg

6S1/2-6P1/2 transition of Cs atoms in cubic and hexagonal solid ⁴He

Hofer, Adrian ; Moroshkin, Peter ; Ulzega, Simone ; Nettels, Daniel ; Müller-Siebert, Reinhard ; Weis, Antoine

In: Physical Review A, 2007, vol. 76, no. 2, p. 022502

We present a systematic experimental study of the absorption and fluorescence spectra of the 6S1/2-6P1/2 transition in Cs atoms isolated in solid ⁴He matrices. The bubble model developed earlier for alkali-metal atoms in liquid He is revised and applied to the present system. The analysis of the dependencies of absorption and fluorescence wavelengths on He...

Université de Fribourg

Acoustic and visual display of photons: a handheld demonstration device

Dimitrova, L. ; Lechkov, A. ; Grigorova, T. ; Weis, Antoine

In: Physica Scripta, 2012, vol. 2012, no. T149, p. 014010

A handheld device for rendering the signals produced by individual photons is presented in this paper. Electric pulses produced by individual photons in a photomultiplier are made audible by a small loudspeaker built into the housing. Output connectors allow the pulse signals to be displayed by an external amplifier/loudspeaker system, an oscilloscope, or to be further processed by pulse counting...

Université de Fribourg

Additional results from the first dedicated search for neutron–mirror–neutron oscillations

Bodek, K. ; Kistryn, S. ; Kuźniak, M. ; Zejma, J. ; Burghoff, M. ; Knappe-Grüneberg, S. ; Sander-Thoemmes, T. ; Schnabel, A. ; Trahms, L. ; Ban, G. ; Lefort, T. ; Naviliat-Cuncic, O. ; Khomutov, N. ; Knowles, Paul E. ; Pazgalev, Anatoly S. ; Weis, Antoine ; Rogel, G. ; Quéméner, G. ; Rebreyend, D. ; Roccia, S. ; Bison, Georg ; Severijns, N. ; Eberhardt, K. ; Hampel, G. ; Heil, W. ; Kratz, J.V. ; Lauer, T. ; Plonka-Spehr, C. ; Sobolev, Yu. ; Wiehl, N. ; Altarev, I. ; Fierlinger, P. ; Gutsmiedl, E. ; Paul, S. ; Stoepler, R. ; Daum, M. ; Henneck, R. ; Kirch, K. ; Knecht, A. ; Lauss, B. ; Mtchedlishvili, A. ; Petzoldt, G. ; Zsigmond, G.

In: Nuclear Instruments and Methods in Physics Research Section A, 2009///doi: 10.1016/j.nima.2009.07.047

The existence of a mirror world holding a copy of our ordinary particle spectrum could lead to oscillations between the neutron (n) and its mirror partner (n′). Such oscillations could manifest themselves in storage experiments with ultracold neutrons whose storage lifetime would depend on the applied magnetic field. Here, extended details and measurements from the first dedicated experimental...

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

An arbitrary-function light power controller

Grujić, Zoran D. ; Piller, Jari ; Weis, Antoine

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.

Université de Fribourg

Atomic and molecular defects in solid ⁴He

Moroshkin, Peter ; Hofer, Adrian ; Weis, Antoine

In: Physics Reports, 2008, vol. 469, no. 1, p. 1-57

The studies of defects formed by impurity particles (atoms, molecules, exciplexes, clusters, free electrons, and positive ions) embedded in liquid and solid ⁴He are reviewed. The properties of free electrons and neutral particles in condensed helium are described by the electron (atomic) bubble model, whereas for the positive ions a snowball structure is considered. We compare the properties of...

Université de Fribourg

Atomic bubbles in impurity-stabilized solid ⁴He

Lebedev, Victor ; Moroshkin, Peter ; Weis, Antoine

In: Fizika Nizkikh Temperatur, 2010, vol. 35, no. 4, p. 391-395

The optical absorption and fluorescence spectra of alkali atoms isolated in liquid and solid He matrices depend on specific macroscopic matrix properties, such as their molar volume and (anisotropic) elasticity constants, and provide thus information about the quantum matrix. We have applied optical spectroscopy to investigate the properties of a recently discovered impurity-stabilized doped...

Université de Fribourg

Atomic magnetic resonance induced by amplitude-, frequency-, or polarization-modulated light

Grujić, Zoran D. ; Weis, Antoine

In: Physical Review A, 2013, vol. 88, no. 1, p. 012508

In recent years diode laser sources have become widespread and reliable tools in magneto-optical spectroscopy. In particular, laser-driven atomic magnetometers have found a wide range of practical applications. More recently, so-called magnetically silent variants of atomic magnetometers have been developed. While in conventional magnetometers the magnetic resonance transitions between atomic...

Université de Fribourg

A Bell-Bloom experiment with polarization-modulated light of arbitrary duty cycle

Fescenko, Ilja ; Knowles, Paul E. ; Weis, Antoine ; Breschi, Evelina

In: Optics Express, 2013, vol. 21, no. 13, p. 15121–15130

We report on a study of polarization-modulation experiments on the 4 → 3 hyperfine component of the D₁ transition in Cs vapor contained in a paraffin-coated cell. The laser beam’s polarization was switched between left- and right-circular polarization at a rate of 200 Hz. Variations of the transmitted light power were recorded while varying the amplitude of a transverse magnetic...

Université de Fribourg

Calculation of the forbidden electric tensor polarizabilities of free Cs atoms and of Cs atoms trapped in a solid ⁴He matrix

Hofer, Adrian ; Moroshkin, Peter ; Ulzega, Simone ; Weis, Antoine

In: Physical Review A, 2008, vol. 77, no. 12, p. 012502

We give a detailed account on our semiempirical calculations of the forbidden electric tensor polarizability α₂⁽³⁾ of the ground state of free Cs atoms and of Cs atoms implanted in a solid 4He matrix. The results are compared with measurements of α₂⁽³⁾ in the free atoms [Europhys. Lett. 76, 1074 (2006)] and in He-trapped atoms [Phys. Rev. A 75, 042505 (2007)]. Features with...