194 research outputs found
Hyper-complex four-manifolds from the Tzitz\'eica equation
It is shown how solutions to the Tzitz\'eica equation can be used to
construct a family of (pseudo) hyper-complex metrics in four dimensions.Comment: To be published in J.Math.Phy
Matter-wave laser Interferometric Gravitation Antenna (MIGA): New perspectives for fundamental physics and geosciences
The MIGA project aims at demonstrating precision measurements of gravity with
cold atom sensors in a large scale instrument and at studying the associated
applications in geosciences and fundamental physics. The first stage of the
project (2013-2018) will consist in building a 300-meter long optical cavity to
interrogate atom interferometers and will be based at the low noise underground
laboratory LSBB in Rustrel, France. The second stage of the project (2018-2023)
will be dedicated to science runs and data analyses in order to probe the
spatio-temporal structure of the local gravity field of the LSBB region, a site
of high hydrological interest. MIGA will also assess future potential
applications of atom interferometry to gravitational wave detection in the
frequency band Hz hardly covered by future long baseline optical
interferometers. This paper presents the main objectives of the project, the
status of the construction of the instrument and the motivation for the
applications of MIGA in geosciences. Important results on new atom
interferometry techniques developed at SYRTE in the context of MIGA and paving
the way to precision gravity measurements are also reported.Comment: Proceedings of the 50th Rencontres de Moriond "100 years after GR",
La Thuile (Italy), 21-28 March 2015 - 10 pages, 5 figures, 23 references
version2: added references, corrected typo
Fluid dynamics of partially radiative blast waves
We derive a self similar solution for the propagation of an extreme
relativistic (or Newtonian) radiative spherical blast wave into a surrounding
cold medium. The solution is obtained under the assumption that the radiation
process is fast, it takes place only in the vicinity of the shock and that it
radiates away a fixed fraction of the energy generated by the shock. In the
Newtonian regime these solutions generalize the Sedov-Taylor adiabatic solution
and the pressure-driven fully radiative solution. In the extreme relativistic
case these solutions generalize the Blandford-McKee adiabatic solution. They
provide a new fully radiative extreme relativistic solution which is different
from the Blandford-McKee fully radiative relativistic solution. This new
solution develops a hot interior which causes it to cool faster than previous
estimates. We find that the energy of the blast wave behaves as a power law of
the location of the shock. The power law index depends on the fraction of the
energy emitted by the shock. We obtain an analytic solution for the interior of
the blast wave. These new solutions might be applicable to the study of GRB
afterglow or SNRs.Comment: 30 LaTeX pages including nine postscript figure
Tzitz\'eica transformation is a dressing action
We classify the simplest rational elements in a twisted loop group, and prove
that dressing actions of them on proper indefinite affine spheres give the
classical Tzitz\'eica transformation and its dual. We also give the group point
of view of the Permutability Theorem, construct complex Tzitz\'eica
transformations, and discuss the group structure for these transformations
ELGAR - A European Laboratory for Gravitation and Atom-interferometric Research
Gravitational waves (GWs) were observed for the first time in 2015, one century after Einstein predicted their existence. There is now growing interest to extend the detection bandwidth to low frequency. The scientific potential of multi-frequency GW astronomy is enormous as it would enable to obtain a more complete picture of cosmic events and mechanisms. This is a unique and entirely new opportunity for the future of astronomy, the success of which depends upon the decisions being made on existing and new infrastructures. The prospect of combining observations from the future space-based instrument LISA together with third generation ground based detectors will open the way toward multi-band GW astronomy, but will leave the infrasound (0.1â10 Hz) band uncovered. GW detectors based on matter wave interferometry promise to fill such a sensitivity gap. We propose the European Laboratory for Gravitation and Atom-interferometric Research (ELGAR), an underground infrastructure based on the latest progress in atomic physics, to study spaceâtime and gravitation with the primary goal of detecting GWs in the infrasound band. ELGAR will directly inherit from large research facilities now being built in Europe for the study of large scale atom interferometry and will drive new pan-European synergies from top research centers developing quantum sensors. ELGAR will measure GW radiation in the infrasound band with a peak strain sensitivity of 3.3 x 10 [hoch]-20 / [Wurzel] Hz at 1.7 Hz. The antenna will have an impact on diverse fundamental and applied research fields beyond GW astronomy, including gravitation, general relativity, and geology
ELGARâa European Laboratory for Gravitation and Atom-interferometric Research
Gravitational waves (GWs) were observed for the first time in 2015, one century after Einstein predicted their existence. There is now growing interest to extend the detection bandwidth to low frequency. The scientific potential of multi-frequency GW astronomy is enormous as it would enable to obtain a more complete picture of cosmic events and mechanisms. This is a unique and entirely new opportunity for the future of astronomy, the success of which depends upon the decisions being made on existing and new infrastructures. The prospect of combining observations from the future space-based instrument LISA together with third generation ground based detectors will open the way toward multi-band GW astronomy, but will leave the infrasound (0.1â10 Hz) band uncovered. GW detectors based on matter wave interferometry promise to fill such a sensitivity gap. We propose the European Laboratory for Gravitation and Atom-interferometric Research (ELGAR), an underground infrastructure based on the latest progress in atomic physics, to study spaceâtime and gravitation with the primary goal of detecting GWs in the infrasound band. ELGAR will directly inherit from large research facilities now being built in Europe for the study of large scale atom interferometry and will drive new pan-European synergies from top research centers developing quantum sensors. ELGAR will measure GW radiation in the infrasound band with a peak strain sensitivity of at 1.7 Hz. The antenna will have an impact on diverse fundamental and applied research fields beyond GW astronomy, including gravitation, general relativity, and geology.AB acknowledges support from the ANR (project EOSBECMR), IdEx BordeauxâLAPHIA (project OE-TWR), theQuantERA ERA-NET (project TAIOL) and the Aquitaine Region (projets IASIG3D and USOFF).XZ thanks the China Scholarships Council (No. 201806010364) program for financial support. JJ thanks âAssociationNationale de la Recherche et de la Technologieâ for financial support (No. 2018/1565).SvAb, NG, SL, EMR, DS, and CS gratefully acknowledge support by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under Grants No. DLRâŒ50WM1641 (PRIMUS-III), 50WM1952 (QUANTUS-V-Fallturm), and 50WP1700 (BECCAL), 50WM1861 (CAL), 50WM2060 (CARIOQA) as well as 50RK1957 (QGYRO)SvAb, NG, SL, EMR, DS, and CS gratefully acknowledge support by âNiedersĂ€chsisches Vorabâ through the âQuantum- and Nano-Metrology (QUANOMET)â initiative within the project QT3, and through âFörderung von Wissenschaft und Technik in Forschung und Lehreâ for the initial funding of research in the new DLR-SI Institute, the CRC 1227 DQ-mat within the projects A05 and B07DS gratefully acknowledges funding by the Federal Ministry of Education and Research (BMBF) through the funding program Photonics Research Germany under contract number 13N14875.RG acknowledges Ville de Paris (Emergence programme HSENS-MWGRAV), ANR (project PIMAI) and the Fundamental Physics and Gravitational Waves (PhyFOG) programme of Observatoire de Paris for support. We also acknowledge networking support by the COST actions GWverse CA16104 and AtomQT CA16221 (Horizon 2020 Framework Programme of the European Union).The work was also supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under Grant Nos.âŒ50WM1556, 50WM1956 and 50WP1706 as well as through the DLR Institutes DLR-SI and DLR-QT.PA-S, MN, and CFS acknowledge support from contracts ESP2015-67234-P and ESP2017-90084-P from the Ministry of Economy and Business of Spain (MINECO), and from contract 2017-SGR-1469 from AGAUR (Catalan government).SvAb, NG, SL, EMR, DS, and CS gratefully acknowledge support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germanyâs Excellence StrategyâEXC-2123 QuantumFrontiersâ390837967 (B2) andCRC1227 âDQ-matâ within projects A05, B07 and B09.LAS thanks Sorbonne UniversitĂ©s (Emergence project LORINVACC) and Conseil Scientifique de l'Observatoire de Paris for funding.This work was realized with the financial support of the French State through the âAgence Nationale de la Rechercheâ (ANR) in the frame of the âMRSEIâ program (Pre-ELGAR ANR-17-MRS5-0004-01) and the âInvestissement d'Avenirâ program (Equipex MIGA: ANR-11-EQPX-0028, IdEx BordeauxâLAPHIA: ANR-10-IDEX-03-02).Peer Reviewe
ELGAR -- a European Laboratory for Gravitation and Atom-interferometric Research
Gravitational Waves (GWs) were observed for the first time in 2015, one
century after Einstein predicted their existence. There is now growing interest
to extend the detection bandwidth to low frequency. The scientific potential of
multi-frequency GW astronomy is enormous as it would enable to obtain a more
complete picture of cosmic events and mechanisms. This is a unique and entirely
new opportunity for the future of astronomy, the success of which depends upon
the decisions being made on existing and new infrastructures. The prospect of
combining observations from the future space-based instrument LISA together
with third generation ground based detectors will open the way towards
multi-band GW astronomy, but will leave the infrasound (0.1 Hz to 10 Hz) band
uncovered. GW detectors based on matter wave interferometry promise to fill
such a sensitivity gap. We propose the European Laboratory for Gravitation and
Atom-interferometric Research (ELGAR), an underground infrastructure based on
the latest progress in atomic physics, to study space-time and gravitation with
the primary goal of detecting GWs in the infrasound band. ELGAR will directly
inherit from large research facilities now being built in Europe for the study
of large scale atom interferometry and will drive new pan-European synergies
from top research centers developing quantum sensors. ELGAR will measure GW
radiation in the infrasound band with a peak strain sensitivity of at 1.7 Hz. The antenna will have an impact on
diverse fundamental and applied research fields beyond GW astronomy, including
gravitation, general relativity, and geology
- âŠ