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Sébastien Clesse
External collaborator
Member since September 2007
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Past projects
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I am involved in the following research directions:

Cosmic inflation

The first measurements of acoustic peaks in the CMB anisotropies strongly suggest that the birth of cosmological fluctuations may have taken place during an early inflationary era of the universe.
In this domain, our activities deal with the construction of explicit models of inflation as well as the extraction of their observable consequences. Our fields of expertise comprise some actively debated subjects as the existence of features (e.g. trans-Planckian effects), inflation with non-minimally coupled scalar fields, DBI- and brane inflation as in the context of String Theory.
For all these theories, we are maintaining various numerical tools such as the ASPIC and FieldInf librairies allowing to compute reheating-consistent predictions for comparison with cosmological data.

External collaborators: Jérôme Martin (IAP, Paris, France), Vincent Vennin (Portsmouth, U.K.), Sébastien Clesse (RWTH, Aachen, Germany).

Cosmological data

Our expertise on inflation and cosmic strings is involved in the CMB data analysis of the PLANCK satellite.
Our current efforts concern the study of future CMB polarization experiments, ground based, and in space, as the CORE satellite.
We are part of the EUCLID collaboration and interested in the impact of high precision measurements of the matter power spectra of the large scale structures for cosmic inflation.
We are also involved in the LISA project, the giant space interferometer dedicated to gravitational wave astronomy, which should open a new window on cosmic string physics and other early universe phenomena.
Another direction concerns the 21cm cosmological radiation. This radiation is emitted by neutral hydrogen atoms and should shed light into the so-called "dark ages": from the recombination to the reionisation of the universe by the first stars. This new observable is expected to be sensitive to the nature of dark matter as well as to some properties of the inflationary era.

External collaborators: Sébastien Clesse (RWTH, Aachen), V. Vennin (Portsmooth, U.K.), CORE Coll., Euclid Coll., eLISA Coll.

Publications in CP3
All my publications on Inspire


Cosmology in the era of Euclid and the Square Kilometre Array
Sprenger, Tim and Archidiacono, Maria and Brinckmann, Thejs and Clesse, Sébastien and Lesgourgues, Julien
[Abstract] [PDF] 48 pages, 11 figures, 8 tables
Refereed paper. 6th February.


LIGO Lo(g)Normal MACHO: Primordial Black Holes survive SN lensing constraints
Garcia-Bellido, Juan and Clesse, Sebastien and Fleury, Pierre
[Abstract] [PDF] [Journal] 7 pages, 7 figures
Refereed paper. 21st December.
Seven Hints for Primordial Black Hole Dark Matter
Clesse, Sebastien and García-Bellido, Juan
[Abstract] [PDF] [Journal] 11 pages, 3 figures
Refereed paper. 21st December.
Constraints from microlensing experiments on clustered primordial black holes
García-Bellido, Juan and Clesse, Sebastien
[Abstract] [PDF] [Journal] 6 pages, 3 figures
Refereed paper. 21st December.


Observational signatures of a non-singular bouncing cosmology
Marc Lilley, Larissa Lorenz, Sebastien Clesse
[Abstract] [PDF] [Journal] Published in JCAP 06 (2011) 004.
Refereed paper. 19th April.


Hybrid inflation along waterfall trajectories
Sébastien Clesse
[Abstract] [PDF] [Journal] updated version accepted for publication in Phys.Rev.D.
Refereed paper. 23rd June.
Initial conditions in hybrid inflation: exploration by MCMC technique
Sébastien Clesse
[Abstract] [PDF] Proceedings of the 2010 Moriond Conference - Cosmology Session
Contribution to proceedings. 23rd June.
Anamorphosis in Hybrid Inflation: How to avoid fine-tuning of Initial Conditions?
Sébastien Clesse
[Abstract] [PDF] [Journal] AIP Proceedings of the "Invisible Universe" conference, Palais de l'Unesco, Paris, 29th June to 4th July 2008.
Contribution to proceedings. 2nd February.


Fractal initial conditions and natural parameter values in hybrid inflation
Sébastien Clesse, Christophe Ringeval, Jonathan Rocher
[Abstract] [PDF] [Journal] Published in Phys. Rev. D80, 123534 (2009)
Refereed paper. 2nd September.


Avoiding the blue spectrum and the fine-tuning of initial conditions in hybrid inflation
Sébastien Clesse and Jonathan Rocher
[Abstract] [PDF] [Journal] Published in Phys. Rev. D79, 103507 (2009)
Refereed paper. 26th September.

[UCLouvain] - [SST] [IRMP] - [SC]
Contact : Jérôme de Favereau
Job opportunities Post-doctoral positions in BSM phenomenology at colliders and in astrophysics
Postdoctoral Position on advanced analysis techniques applied to the CMS di-Higgs study
Post-doctoral positions in collider phenomenology and particle astrophysics
EOS be.h : 10 PhD positions