6,318 research outputs found
A Model for Type-IIP Supernovae with Medium Recombination Approximation
In this paper, we propose a new light-curve model for Type-IIP supernovae
(SNe IIP) with an approximation of medium recombination. Recombination of
hydrogen that takes place in the envelope is believed highly affect the light
curves of SNe IIP. The propagation of the recombination wave through the
expanding envelope is crucial to determine the temperature and the bolometric
luminosity. Several approximations were made in previous works to determine the
recombination front, which plays a role as the pseudo-photosphere. With the
Eddington boundary condition, we let the actual photosphere be the boundary to
determine the time evolution of temperature profile of the envelope and
calculate the bolometric luminosity. A new approximation on the speed of
recombination wave is introduced to get a closer result to the real situation.
We abandon the non-self-consistent approximations made in former works and
solve the initial hump problem in the previous attempt for the slow
recombination approximation. The produced light curves show the necessity of
this approximation and fit the observation well.Comment: 14 pages, 10 figures, 5 tables. Submitted to ApJ, welcome for
comments
Individual position diversity in dependence socioeconomic networks increases economic output
The availability of big data recorded from massively multiplayer online
role-playing games (MMORPGs) allows us to gain a deeper understanding of the
potential connection between individuals' network positions and their economic
outputs. We use a statistical filtering method to construct dependence networks
from weighted friendship networks of individuals. We investigate the 30
distinct motif positions in the 13 directed triadic motifs which represent
microscopic dependences among individuals. Based on the structural similarity
of motif positions, we further classify individuals into different groups. The
node position diversity of individuals is found to be positively correlated
with their economic outputs. We also find that the economic outputs of leaf
nodes are significantly lower than that of the other nodes in the same motif.
Our findings shed light on understanding the influence of network structure on
economic activities and outputs in socioeconomic system.Comment: 19 pages, 5 figure
Single photo-electron trapping, storage, and detection in a one-electron quantum dot
There has been considerable progress in electro-statically emptying, and
re-filling, quantum dots with individual electrons. Typically the quantum dot
is defined by electrostatic gates on a GaAs/AlGaAs modulation doped
heterostructure. We report the filling of such a quantum dot by a single
photo-electron, originating from an individual photon. The electrostatic dot
can be emptied and reset in a controlled fashion before the arrival of each
photon. The trapped photo-electron is detected by a point contact transistor
integrated adjacent to the electrostatic potential trap. Each stored
photo-electron causes a persistent negative step in the transistor channel
current. Such a controllable, benign, single photo-electron detector could
allow for information transfer between flying photon qubits and stored electron
qubits.Comment: 4 Pages, 5 Figure
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