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UID:0-603@lptms.universite-paris-saclay.fr
DTSTART:20180927T140000Z
DTEND:20180927T170000Z
DTSTAMP:20180910T065100Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the
 se-ines-rodriguez-arias/
SUMMARY:Soutenance de thèse: Ines Rodriguez-Arias - IPN-batiment 100\, Aud
 itoriurm - 27 Sep 18 14:00
DESCRIPTION:Soutenance de thèse:\nCollective behaviors in interacting spin
  systems\npar\n\nInès Rodriguez-Arias\nJury:\n\n 	Cécile Monthus\, IPhT\
 , CEA-Saclay\, présidente\n 	Juan Garrahan\, University of Notthingham\, 
 rapporteur\n 	Nicolas Laflorencie\, LPT Université Paul Sabatier\, rappor
 teur\n 	Cristiano Ciuti\, MPQ Université Paris Diderot\, examinateur\n 	G
 eoffrey Bodenhausen\, Département de Chimie\, ENS\, examinateur\n 	Andrea
  De Luca\, University of Oxford\, invité.\n 	Alberto Rosso\, LPTMS\, Univ
 ersité Paris-Sud\, directeur de thèse\n\nRésumé: Dynamic nuclear polar
 ization (DNP) is one of the most promising techniques towards a new genera
 tion of Magnetic Resonance Imaging (MRI). The idea is to use the Nuclear M
 agnetic Resonance (NMR) in other nuclei rather than the traditional hydrog
 en\, such as carbon. For the carbon signal to be detected\, one needs to e
 nhance its spin polarization. In thermal equilibrium — at low temperatur
 e and high magnetic field — electron spins are far more polarized than a
 ny system of nuclear spins\, which is due to their smaller mass. With the 
 DNP technique we bring the system out-of- equilibrium irradiating it with 
 microwaves. This triggers polarization transfer from the electron spins to
  the nuclear ones.\nDuring my Ph.D\, I have studied both analytically and 
 numerically the competition between the dipolar interactions among electro
 n spins (which can be tuned experimentally) and the disorder naturally pre
 sent in the sample. I proposed two models to study DNP: a Heisenberg spin-
 chain and a system of free-fermions in the Anderson model. Two different r
 egimes were found :\n(I) For strongly interacting electron spins\, the out
 -of-equilibrium steady state displays an effective thermodynamic behavior 
 characterised by a very low spin temperature.\n(II) In the weakly interact
 ing regime\, it is not possible to define a spin temperature\, and it is a
 ssociated to a many-body localized phase (or an Anderson-localized phase).
 \nMy research was focused on the properties of the two phases with respect
  to the performance of DNP\, and I found it to be optimal at the transitio
 n between the two. This is a very important result that has been verified 
 by recent experiments carried in École Normale Supérieure de Paris.
CATEGORIES:seminars
LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay
 \, France
GEO:48.698196;2.181773
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\,
  orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm:
 geo:48.698196,2.181773
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