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CATEGORIES:Theoretical Physics Seminars
SUMMARY:A cascade of delocalization transitions and many-b
ody localization in the interpolating Aubry-André-
Fibonacci model - Antonio Strkalj\, University of
Cambridge
DTSTART:20220303T131500Z
DTEND:20220303T143000Z
UID:TALK4762AT
URL:/talk/index/4762
DESCRIPTION:Model Hamiltonians with quasiperiodic order displa
y a hierarchy of phenomena at different scales and
are excellent starting points to explore unconven
tional effects not achievable in periodic solids.
In this talk\, I will present a theoretical study
of localization in a one-dimensional interpolating
Aubry-André-Fibonacci (IAAF) model. This model co
ntinuously interpolates between two well-known qua
siperiodic examples: the Aubry-André model\, known
for a metal-to-insulator transition at finite pot
ential strength\, and the Fibonacci model\, which
is always critical. In a single-particle case\, co
ntrary to what one would naively expect\, we find
that the IAAF model has a non-monotonous and non-u
niform behaviour of the spectrum. More precisely\,
we discover that by controllably evolving an Aubr
y-André into a Fibonacci model\, a series of local
ization-delocalization transitions take place befo
re the spectrum becomes critical. In a many-body I
AAF model\, we find that interactions between part
icles extend the ergodic phase in the Aubry-André
limit\, whereas they shrink it in the Fibonacci li
mit. The cascade of localization transitions found
in the single-particle case is destroyed even for
weak interactions. Moreover\, in the region of th
e parameter space where the single-particle spectr
um contains a non-trivial mobility edge\, an anoma
lous effect is observed with tuning the many-body
interactions\, namely\, weak interactions localize
the system\, whereas stronger interactions enhanc
e ergodicity.
LOCATION:Theory Library
CONTACT:Dr Hannah Price
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