Speaker
Dr
Pietro Massignan
(ICFO - Institute of Photonic Sciences)
Description
A class of gapped many-body systems displays zero-
energy (Majorana) quasiparticles with non-Abelian
statistics and as a consequence possesses peculiar
topological phases [1, 2]. We discuss here how these
arise naturally in fermionic superfluids in 2D optical
lattices, in two different scenarios which may be soon
realized experimentally.
In first instance, we show how to create a stable p-
wave superfluid using bosons mixed with a single
species of fermions [3]. We analyze with a self-
consistent method its excitation spectrum in presence of
a vortex, and we point out the most favorable range of
interaction strengths in which the zero-energy mode
with topological character may be observed on a finite
optical lattice.
We also discuss how topological phases appear in
imbalanced two-component Fermi superfluids with
standard s-wave interactions, when the gas is exposed
to a synthetic non-Abelian magnetic field [4, 5]. We
present the complete topological phase diagram, and we
analyze the connection between Chern numbers and the
existence of topologically protected edge modes.
Moreover, we address the issue of superfluidity
breakdown by spin imbalance, indicating which of the
regions in the phase diagram are experimentally
accessible.
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References
[1] C. Nayak, S. Simon, A. Stern, M. Freedman, and S.
Das Sarma, Rev. Mod. Phys. 80, 1083 (2008).
[2] N. Read and D. Green, Phys. Rev. B 61, 10267
(2000).
[3] P. Massignan, A. Sanpera, and M. Lewenstein, Phys.
Rev. A 81, 031607(R) (2010).
[4] M. Sato, Y. Takahashi, and S. Fujimoto, Phys. Rev.
Lett. 103, 020401 (2009).
[5] A. Kubasiak, P. Massignan, and M. Lewenstein,
Europhys. Lett. 92, 46004 (2011)
Primary author
Dr
Pietro Massignan
(ICFO - Institute of Photonic Sciences)
