Publications associées à Hélium

Ultrahigh-quality-factor micro- and nanomechanical resonators using dissipation dilution

Tobias Kippenberg, Alberto Beccari, Nils Johan Engelsen

Mechanical resonators are widely used in sensors, transducers and optomechanical systems, where mechanical dissipation sets the ultimate limit to performance. Over the past 15 years, the quality factors in strained mechanical resonators have increased by f ...

Nature Portfolio2024

White dwarfs as a probe of exceptionally light QCD axions

We study the effects of exceptionally light QCD axions on the stellar configuration of white dwarfs. At finite baryon density, the nonderivative coupling of the axion to nucleons displaces the axion from its invacuum minimum, which implies a reduction of t ...

American Physical Society2024

Validation of 2D T e and n e measurements made with Helium imaging spectroscopy in the volume of the TCV divertor

Basil Duval, Patrick Blanchard, Holger Reimerdes, Christian Gabriel Theiler, Artur Perek, Dmytry Mykytchuk, Cedric Kar-Wai Tsui, Hugo De Oliveira, Filippo Bagnato, Lorenzo Martinelli

Multi-spectral imaging of helium atomic emission (HeMSI) has been used to create 2D poloidal maps of T-e and ne in TCV's divertor. To achieve these measurements, TCV's MANTIS multispectral cameras (Perek et al 2019 Rev. Sci. Instrum. 90 123514) simultaneou ...

IOP Publishing Ltd2023

Engineering SYK Interactions in Disordered Graphene Flakes under Realistic Experimental Conditions

Oleg Yazyev, Marta Agnieszka Brzezinska, Yifei Guan

We model interactions following the Sachdev-Ye-Kitaev (SYK) framework in disordered graphene flakes up to 300 000 atoms in size (-100 nm in diameter) subjected to an out-of-plane magnetic field B of 5-20 Tesla within the tight-binding formalism. We investi ...

AMER PHYSICAL SOC2023

Progress in the design and manufacturing of the EDIPO 2 cryostat

Pierluigi Bruzzone, Kamil Sedlák, Roberto Guarino, Evgeny Solodko

A major upgrade of the European DIPOle (EDIPO) test facility, which will allow the testing of superconducting samples both for fusion and for high-energy physics applications, is taking place at the Swiss Plasma Center. With a target background field of 15 ...

2023

Search for K+ decays into the π+e+e-e+e- final state

Alessandro Mapelli, Radoslav Marchevski, Alina Kleimenova

The first search for ultra-rare K+ decays into the pi(+)e(+)e(-) e(+) e(-) final state is reported, using a dataset collected by the NA62 experiment at CERN in 2017-2018. An upper limit of 1.4x10(-8) at 90% CL is obtained for the branching ratio of the K+ ...

Elsevier2023

The competing effects of wave amplitude and collisions on multi-ion species suppression of stimulated Brillouin scattering in inertial confinement fusion Hohlraums

Stephan Brunner

Reduction in stimulated Brillouin scattering (SBS) from National Ignition Facility Hohlraums has been predicted through the use of multi-ion species materials on Hohlraum walls. This approach to controlling SBS is based upon introducing a lighter ion speci ...

2023

Experimental study of stability, quench propagation and detection methods on 15 kA sub-scale HTS fusion conductors in SULTAN

Pierluigi Bruzzone, Kamil Sedlák, Nikolay Bykovskiy, Ortensia Dicuonzo

High-temperature superconductors (HTSs) enable exclusive operating conditions for fusion magnets, boosting their performance up to 20 T generated magnetic fields in the temperature range from 4 K to 20 K. One of the main technological issues of HTS conduct ...

2023

Many-body physics with strongly interacting fermions coupled to light

Victor Youri Helson

This thesis reports on the realization of the first experiments conducted with superfluid, strongly interacting Fermi gases of 6Li coupled to the light field of an optical cavity. In the scope of existing ultracold atomic platforms, this is the first time ...

EPFL2023

In situ work function measurements of W, WO3 nanostructured surfaces

Francisco Sanchez

Surface nanostructuring enables the fabrication of materials with highly desirable properties. Nanostructured tungsten surfaces have potential applications in solar water splitting. Exposing a polished tungsten surface to helium plasma induces various surf ...

ELSEVIER SCIENCE SA2022