279,234 research outputs found
Creating and manipulating non-Abelian anyons in cold atom systems using auxiliary bosons
The possibility of realizing bosonic fractional quantum Hall effect in
ultra-cold atomic systems suggests a new route to producing and manipulating
anyons, by introducing auxiliary bosons of a different species that capture
quasiholes and thus inherit their non-trivial braiding properties. States with
localized quasiholes at any desired locations can be obtained by annihilating
the auxiliary bosons at those locations. We explore how this method can be used
to generate non-Abelian quasiholes of the Moore-Read Pfaffian state for bosons
at filling factor . We show that a Hamiltonian with an appropriate
three-body interaction can produce two-quasihole states in two distinct fusion
channels of the topological "qubit." Characteristics of these states that are
related to the non-Abelian nature can be probed and verified by a measurement
of the effective relative angular momentum of the auxiliary bosons, which is
directly related to their pair distribution function. Moore-Read states of more
than two quasiholes can also be produced in a similar fashion. We investigate
some issues related to the experimental feasibility of this approach, in
particular, how large the systems should be for a realization of this physics
and to what extent this physics carries over to systems with the more standard
two-body contact interaction.Comment: 16 pages, 6 figure
Tunnel transport and interlayer excitons in bilayer fractional quantum Hall systems
In a bilayer system consisting of a composite-fermion Fermi sea in each
layer, the tunnel current is exponentially suppressed at zero bias, followed by
a strong peak at a finite bias voltage . This behavior, which is
qualitatively different from that observed for the electron Fermi sea, provides
fundamental insight into the strongly correlated non-Fermi liquid nature of the
CF Fermi sea and, in particular, offers a window into the short-distance
high-energy physics of this state. We identify the exciton responsible for the
peak current and provide a quantitative account of the value of .
The excitonic attraction is shown to be quantitatively significant, and its
variation accounts for the increase of with the application of an
in-plane magnetic field. We also estimate the critical Zeeman energy where
transition occurs from a fully spin polarized composite fermion Fermi sea to a
partially spin polarized one, carefully incorporating corrections due to finite
width and Landau level mixing, and find it to be in satisfactory agreement with
the Zeeman energy where a qualitative change has been observed for the onset
bias voltage [Eisenstein et al., Phys. Rev. B 94, 125409 (2016)]. For
fractional quantum Hall states, we predict a substantial discontinuous jump in
when the system undergoes a transition from a fully spin
polarized state to a spin singlet or a partially spin polarized state.Comment: 14 pages, 14 figure
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