In: Physical Review E, 2020, vol. 101, no. 1, p. 012120
The Fokker-Planck equation provides a complete statistical description of a particle undergoing random motion in a solvent. In the presence of Lorentz force due to an external magnetic field, the Fokker-Planck equation picks up a tensorial coefficient, which reflects the anisotropy of the particle's motion. This tensor, however, cannot be interpreted as a diffusion tensor; there are...
|
In: New Journal of Physics, 2020, vol. 22, no. 9, p. 093057
We study the motion of a Brownian particle subjected to Lorentz force due to an external magnetic field. Each spatial degree of freedom of the particle is coupled to a different thermostat. We show that the magnetic field results in correlation between different velocity components in the stationary state. Integrating the velocity autocorrelation matrix, we obtain the diffusion matrix that...
|
In: Advanced Materials Interfaces, 2020, vol. 7, no. 23, p. 2001227
Nanostructured silver stands out among other plasmonic materials because its optical losses are the lowest of all metals. However, nanostructured silver rapidly degrades under ambient conditions, preventing its direct use in most plasmonic applications. Here, a facile and robust method for the preparation of highly stable nanostructured silver morphologies is introduced. 3D nanostructured...
|
In: Physical Review A, 2019, vol. 99, no. 4, p. 042112
Magnetic-field uniformity is of the utmost importance in experiments to measure the electric dipole moment of the neutron. A general parametrization of the magnetic field in terms of harmonic polynomial modes is proposed, going beyond the linear- gradients approximation. We review the main undesirable effects of nonuniformities: depolarization of ultracold neutrons and Larmor frequency shifts...
|
In: Physical Review X, 2017, vol. 7, no. 4, p. 041034
We report on a search for ultralow-mass axionlike dark matter by analyzing the ratio of the spin-precession frequencies of stored ultracold neutrons and 199Hg atoms for an axion-induced oscillating electric dipole moment of the neutron and an axion-wind spin-precession effect. No signal consistent with dark matter is observed for the axion mass range 10−24≤ma≤10−17 eV. Our null result...
|
In: Nature Nanotechnology, 2010, vol. 5, p. 423 - 428
The aggregation of proteins is central to many aspects of daily life, including food processing, blood coagulation, eye cataract formation disease and prion-related neurodegenerative infections. However, the physical mechanisms responsible for amyloidosis—the irreversible fibril formation of various proteins that is linked to disorders such as Alzheimer's, Creutzfeldt–Jakob and Huntington's...
|
Thèse de doctorat : Université de Fribourg, 2002 ; no 1367.
La transition métal-isolant de Mott est étudiée en tant que transition de phase quantique. Le modèle U - t - t’ à demi-remplissage est choisi comme paradigme; le signe de t’ n’est pas pertinent et nous le prendrons positif. Le diagramme de phase présente deux phases isolantes de type Mott, avec des symétries distinctes, et une phase métallique globale, pressentie comme liquide de...
|
In: Applied Magnetic Resonance, 1997, vol. 13, no. 1-2, p. 75-93
|
In: Physics Letters B, 2015, vol. 745, p. 58–63
|
In: Journal of Applied Physics, 2014, vol. 116, no. 8, p. 084510
The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5 m × 2.5 m × 3 m,...
|