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UID:0-650@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20190226T110000
DTEND;TZID=Europe/Paris:20190226T120000
DTSTAMP:20190214T084519Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
s-patrick-azaria/
SUMMARY:Séminaire du LPTMS: Patrick Azaria - LPTMS\, salle 201\, 2ème ét
age\, Bât 100\, Campus d'Orsay - 26 Fév 19 11:00
DESCRIPTION:Topological States in Massless One-dimensional Fermionic System
s\nPatrick Azaria (LPTMC-Sorbonne Universités)\n\n\nTopological states ar
e characterized by the unique exponentially localized excitations they hos
t at their ends in an open geometry. The topological protections of these
systems relies on the bulk of these systems being gapped. This is the case
in one-dimensional systems for superconductors proximity coupled to a bul
k superconductor. However in a purely one-dimensional system\, where super
conductivity arises from intrinsic charge conserving attractive interactio
ns\, the bulk of the system remains gapless due to large quantum fluctuati
ons of the phase. One may then naturally question the existence of such to
pological phases in the presence of massless bulk excitations. Indeed\, sy
stems of spinless fermions with either attractive or repulsive interaction
s are described by a Luttinger liquid and are topologically trivial: they
display quasi-long range dominant superconducting or 2kF charge density wa
ve instabilities without exponentially localized modes at their ends. In t
his talk I shall show that in coupled chains\, or in interacting multi-fla
vor fermionic systems\, topological states with non trivial end modes may
exist provided there is enough symmetry protection. This includes systems
with tendency toward superconducting order as well as the more seemingly i
nnocuous situations of coupled density waves with repulsive interactions.
In the particular case with N=3 flavors\, I shall argue that a non trivial
topological superconducting phase\, corresponding to the gapless analogue
of the Haldane phase in spin-1 chains\, as well as non trivial chiral gap
less spin density waves phases hosting Z3 parafermionic edge modes may be
stabilized.\n
CATEGORIES:seminars
LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15
Rue Georges Clemenceau\, Orsay\, 91405\, France
GEO:48.698185;2.181768
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\,
Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è
me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768
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