Semilocalization
of disordered spins in cavity QED
Guido Pupillo
University of Strasbourg
Centre Européen de Sciences Quantiques, ISIS (University of
Strasbourg and CNRS)
Abstract:
Light-matter interactions are playing an increasingly crucial role
in the understanding and engineering of new states of matter with
relevance to the fields of quantum optics, solid state physics,
chemistry and materials science. Experiments have shown that
significant modifications of material properties and transport can
occur in a cavity in the regime of collective strong light-matter
coupling even without external irradiation – “in the dark”. In
this colloquium-style talk we focus on disorder -- a key feature
of many materials --, in particular on general models for
disordered spins coupled to the photon field of a cavity. We show
that collective light matter interactions can dramatically alter
the many-particle spin wavefunctions even in the limit of
vanishingly small photon numbers: Subtle, permanent changes in the
wavefunctions result from the combined effects of vacuum
hybridization and long-range cavity-mediated couplings between the
spins. A surprising, general, result is the realization of
“semilocalization”, a famous and elusive effect in quantum
physics, usually associated to critical states of Anderson-like
transitions. We discuss implications for energy transport and
novel quantum phases mediated by long-range couplings in molecular
physics and quantum optical systems.
Short bio:
Guido Pupillo is Distinguished Professor at the University of
Strasbourg and Director of the Centre Européen de Sciences
Quantiques (CESQ) at the Institut de Science et d'Ingénierie
Supramoléculaires (ISIS) of the University of Strasbourg and CNRS,
where he is involved in the development of teaching and research
programs in quantum science and technology. He obtained a Master
in Theoretical Physics at the University of Bologna (IT) and a PhD
in Physics in 2005 at the University of Maryland for research
conducted at the National Institute of Standards and Technology
(US). Until 2011 he was scientist and then senior scientist at the
University of Innsbruck and the Austrian Academy of Sciences (AT),
where he obtained the Habilitation in Theoretical Physics. Since
2012 he is full professor at the University of Strasbourg. He is
recipient of several fellowships and awards, including the 2012
ERC Starting Grant, the 2013 Guy Ourisson Prize and the 2019
senior fellowship of the Institut Universitaire de France (IUF).
His research interests are in atomic, molecular, and optical
physics, quantum simulations and quantum computing.