Publications associées à Virgo (interféromètre)

Model-based electron density estimation using multiple diagnostics on TCV

Olivier Sauter, Federico Alberto Alfredo Felici, Cristian Galperti

Estimation of the dynamic evolution of the electron plasma density during a tokamak discharge is crucial since it directly affects the plasma performance, confinement and stability. Therefore it needs to be monitored and controlled. Knowledge of the densit ...

ELSEVIER SCIENCE SA2023

Strained crystalline nanomechanical resonators with quality factors above 10 billion

Tobias Kippenberg, Sergey Fedorov, Alberto Beccari, Nils Johan Engelsen

In strained mechanical resonators, the concurrence of tensile stress and geometric nonlinearity dramatically reduces dissipation. This phenomenon, called dissipation dilution, is employed in mirror suspensions of gravitational-wave interferometers and at t ...

NATURE PORTFOLIO2022

The GRANDMA network in preparation for the fourth gravitational-wave observing run

Jieping Zhu, Jean-Paul Richard Kneib, Xiao Wang

GRANDMA is a world-wide collaboration with the primary scientific goal of studying gravitational-wave sources, discovering their electromagnetic counterparts and characterizing their emission. GRANDMA involves astronomers, astrophysicists, gravitational-wa ...

SPIE-INT SOC OPTICAL ENGINEERING2022

A simple theoretical model for estimating the frequency characteristics of black hole mergers

Roberto Guarino

Gravitational waves, despite predicted within the Theory of General Relativity about a century ago, were observed experi-mentally only in the last few years, thanks to the recent advances of the LIGO and Virgo detectors. In this work, we introduce a simple ...

2022

Novel Search for High-Frequency Gravitational Waves with Low-Mass Axion Haloscopes

Valerie Fiona Domcke

Gravitational waves (GWs) generate oscillating electromagnetic effects in the vicinity of external electric and magnetic fields. We discuss this phenomenon with a particular focus on reinterpreting the results of axion haloscopes based on lumped-element de ...

2022

Gravitational wave signal from primordial magnetic fields in the Pulsar Timing Array frequency band

Andrii Neronov

The NANOGrav, Parkes, European, and International Pulsar Timing Array (PTA) Collaborations have reported evidence for a common-spectrum process that can potentially correspond to a stochastic gravitational wave background (SGWB) in the 1-100 nHz frequency ...

American Physical Society2022

Perimeter Modes of Nanomechanical Resonators Exhibit Quality Factors Exceeding 10(9) at Room Temperature

Tobias Kippenberg, Alberto Beccari, Amirali Arabmoheghi, Nils Johan Engelsen, Guanhao Huang, Sergey Fedorov

Systems with low mechanical dissipation are extensively used in precision measurements such as gravitational wave detection, atomic force microscopy, and quantum control of mechanical oscillators via optomechanics and electromechanics. The mechanical quali ...

American Physical Society2022

Challenges and opportunities of gravitational-wave searches at MHz to GHz frequencies

Daniel Garcia Figueroa, Valerie Fiona Domcke, Francisco Torrenti

The first direct measurement of gravitational waves by the LIGO and Virgo collaborations has opened up new avenues to explore our Universe. This white paper outlines the challenges and gains expected in gravitational-wave searches at frequencies above the ...

SPRINGER INT PUBL AG2021

Stochastic gravitational-wave background from metastable cosmic strings

Valerie Fiona Domcke

A metastable cosmic-string network is a generic consequence of many grand unified theories (GUTs) when combined with cosmic inflation. Metastable cosmic strings are not topologically stable, but decay on cosmic time scales due to pair production of GUT mon ...

IOP Publishing Ltd2021

Potential of Radio Telescopes as High-Frequency Gravitational Wave Detectors

Valerie Fiona Domcke

In the presence of magnetic fields, gravitational waves are converted into photons and vice versa. We demonstrate that this conversion leads to a distortion of the cosmic microwave background (CMB), which can serve as a detector for MHz to GHz gravitationa ...

2021

From NANOGrav to LIGO with metastable cosmic strings

Valerie Fiona Domcke

We interpret the recent NANOGrav results in terms of a stochastic gravitational wave background from metastable cosmic strings. The observed amplitude of a stochastic signal can be translated into a range for the cosmic string tension and the mass of magne ...

2020

Experimental and numerical study of stochastic branching noise in nuclear reactors

Oskari Ville Pakari

Noise analysis applied to nuclear reactor physics is a powerful tool to investigate a reactor's kinetic parameters, and more generally underlying physical processes determining core behavior. The kinetic parameters are the coefficients of simplified time-d ...

EPFL2020

Probing the gravitational wave background from cosmic strings with LISA

Daniel Garcia Figueroa

Cosmic string networks offer one of the best prospects for detection of cosmological gravitational waves (GWs). The combined incoherent GW emission of a large number of string loops leads to a stochastic GW background (SGWB), which encodes the properties o ...

2020

Development and verification of a methodology for neutron noise response to fuel assembly vibrations

Andreas Pautz, Gaëtan Girardin, Hakim Ferroukhi, Abdelhamid Dokhane, Dionysios Chionis

Nuclear reactors are stochastic systems, in which several parameters fluctuate even during steady-state conditions. In addition, structural components like fuel assemblies, vibrate due to strong hydraulic forces. This stochasticity is the cause of the neut ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Ability of LIGO and LISA to probe the equation of state of the early Universe

Daniel Garcia Figueroa

The expansion history of the Universe between the end of inflation and the onset of radiation-domination (RD) is currently unknown. If the equation of state during this period is stiffer than that of radiation, w > 1/3, the gravitational wave (GW) backgrou ...

IOP PUBLISHING LTD2019

Reconstructing the spectral shape of a stochastic gravitational wave background with LISA

Daniel Garcia Figueroa

We present a set of tools to assess the capabilities of LISA to detect and reconstruct the spectral shape and amplitude of a stochastic gravitational wave background (SGWB). We first provide the LISA power-law sensitivity curve and binned power-law sensiti ...

IOP PUBLISHING LTD2019

Two-Tone Optomechanical Instability and Its Fundamental Implications for Backaction-Evading Measurements

Tobias Kippenberg, Amir Youssefi, Liu Qiu, Itay Shomroni

While quantum mechanics imposes a fundamental limit on the precision of interferometric measurementsof mechanical motion due to measurement backaction, the nonlinear nature of the coupling also leads toparametric instabilities that place practical limits o ...

American Physical Society2019

Fiber Bragg grating-based thermometer for drill bit temperature monitoring

Luc Thévenaz, Kenny Hey Tow

The temperature measurement of a drill bit during an implantology drilling process is proposed by using a fiber Bragg grating fitted inside the drill bit. Due to the rotational nature of the drilling process, a free-space fiber-optic rotary joint is used f ...

2019

Probing non-Gaussian stochastic gravitational wave backgrounds with LISA

Daniel Garcia Figueroa, Nicola Bartolomei, Valerie Fiona Domcke

The stochastic gravitational wave background (SGWB) contains a wealth of information on astrophysical and cosmological processes. A major challenge of upcoming years will be to extract the information contained in this background and to disentangle the con ...

IOP PUBLISHING LTD2018

Advanced gravitational lensing techniques for precision cosmology

Markus Rexroth

Gravitational lensing - the deflection of light by gravity - has greatly developed since its famous first observation in 1919, which validated Einstein's General Theory of Relativity. The strength of this effect does not depend on the nature of the mass wh ...

EPFL2018