9,376 research outputs found
Itinerant chiral ferromagnetism in a trapped Rashba spin-orbit coupled Fermi gas
How ferromagnetic phases emerge in itinerant systems is an outstanding
problem in quantum magnetism. Here we consider a repulsive two-component Fermi
gas confined in a two dimensional isotropic harmonic potential and subject to a
large Rashba spin-orbit (SO) coupling, whose single-particle dispersion can be
tailored by adjusting the SO coupling strength. We show that the interplay
among SO coupling, correlation effects and mean-field repulsion leads to a
competition between ferromagnetic and non-magnetic phases. At intermediate
interaction strengths, ferromagnetic phase emerges which can be well described
by the mean-field Hartree-Fock theory; whereas at strong interaction strengths,
a strongly correlated non-magnetic phase is favored due to the
beyond-mean-field quantum correlation effects. Furthermore, the ferromagnetic
phase of this system possesses a chiral current density induced by the Rashba
spin-orbit coupling, whose experimental signature is investigated.Comment: Main text: 5 pages, 6 figures; Supplement: 4 pages, 2 figure
Atomistic pseudopotential calculations of the optical properties of InAs/InP self-assembled quantum dots
We present a comprehensive study of the optical properties of InAs/InP
self-assembled quantum dots (QDs) using an empirical pseudopotential method and
configuration interaction treatment of the many-particle effects. The results
are compared to those of InAs/GaAs QDs. The main results are: (i) The alignment
of emission lines of neutral exciton, charged exciton and biexciton in InAs/InP
QDs is quite different from that in InAs/GaAs QDs. (ii) The hidden correlation
in InAs/InP QDs is 0.7 - 0.9 meV, smaller than that in InAs/GaAs QDs. (iii) The
radiative lifetimes of neutral exciton, charged exciton and biexciton in
InAs/InP QDs are about twice longer than those in InAs/GaAs QDs. (v) The phase
diagrams of few electrons and holes in InAs/InP QDs differ greatly from those
in InAs/GaAs QDs. The filling orders of electrons and holes are shown to obey
the Hund's rule and Aufbau principle, and therefore the photoluminescence
spectra of highly charged excitons are very different from those of InAs/GaAs
QDs.Comment: 10 pages, 11 figure
An Attention-based Collaboration Framework for Multi-View Network Representation Learning
Learning distributed node representations in networks has been attracting
increasing attention recently due to its effectiveness in a variety of
applications. Existing approaches usually study networks with a single type of
proximity between nodes, which defines a single view of a network. However, in
reality there usually exists multiple types of proximities between nodes,
yielding networks with multiple views. This paper studies learning node
representations for networks with multiple views, which aims to infer robust
node representations across different views. We propose a multi-view
representation learning approach, which promotes the collaboration of different
views and lets them vote for the robust representations. During the voting
process, an attention mechanism is introduced, which enables each node to focus
on the most informative views. Experimental results on real-world networks show
that the proposed approach outperforms existing state-of-the-art approaches for
network representation learning with a single view and other competitive
approaches with multiple views.Comment: CIKM 201
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