2 research outputs found
Fractional quantum Hall state at \nu=1/4 in a wide quantum well
We investigate, with the help of Monte-Carlo and exact-diagonalization
calculations in the spherical geometry, several compressible and incompressible
candidate wave functions for the recently observed quantum Hall state at the
filling factor in a wide quantum well. The quantum well is modeled as
a two-component system by retaining its two lowest subbands. We make a direct
connection with the phenomenological effective-bilayer model, which is commonly
used in the description of a wide quantum well, and we compare our findings
with the established results at in the lowest Landau level. At
, the overlap calculations for the Halperin (5,5,3) and (7,7,1)
states, the generalized Haldane-Rezayi state and the Moore-Read Pfaffian,
suggest that the incompressible state is likely to be realized in the interplay
between the Halperin (5,5,3) state and the Moore-Read Pfaffian. Our numerics
shows the latter to be very susceptible to changes in the interaction
coefficients, thus indicating that the observed state is of multicomponent
nature.Comment: 14 pages, 8 figures; minor changes, accepted for publication in Phys.
Rev.
Type II-P supernovae as standardized candles: improvements using near-infrared data
We present the first near infrared Hubble diagram for type II-P supernovae to
further explore their value as distance indicators. We use a modified version
of the standardised candle method which relies on the tight correlation between
the absolute magnitudes of type II-P supernovae and their expansion velocities
during the plateau phase. Although our sample contains only 12 II-P supernovae
and they are necessarily local (z < 0.02), we demonstrate using near infrared
JHK photometry that it may be possible to reduce the scatter in the Hubble
diagram to 0.1-0.15 magnitudes. While this is potentially similar to the
dispersion seen for type Ia supernovae, we caution that this needs to be
confirmed with a larger sample of II-P supernovae in the Hubble flow.Comment: 6 pages, 1 figure, 1 table, accepted for publication in MNRAS Letter