632 research outputs found
Serial-parallel conversion for single photons with heralding signals
We present serial-parallel conversion for a heralded single photon source
(heralded SPS). We theoretically show that with the heralding signal, the
serial-parallel converter can route a stream of n photons to n different
spatial modes more efficiently than is the case without using a heralding
signal. We also experimentally demonstrate serial-parallel conversion for two
photons generated from a heralded SPS. We achieve a conversion efficiency of
0.533 \pm 0.003, which exceeds the maximum achievable efficiency of 0.5 for
serial-parallel conversion using unheralded photons, and is double the
efficiency (0.25) for that using beamsplitters. When the losses in the optical
converter are corrected for, the efficiency of the current setup can be
increased up to 0.996 \pm 0.006.Comment: 8 pages, 5 figure
Shock-induced star cluster formation in colliding galaxies
We studied the formation process of star clusters using high-resolution
N-body/smoothed particle hydrodynamcs simulations of colliding galaxies. The
total number of particles is 1.2x10^8 for our high resolution run. The
gravitational softening is 5 pc and we allow gas to cool down to \sim 10 K.
During the first encounter of the collision, a giant filament consists of cold
and dense gas found between the progenitors by shock compression. A vigorous
starburst took place in the filament, resulting in the formation of star
clusters. The mass of these star clusters ranges from 10^{5-8} Msun. These star
clusters formed hierarchically: at first small star clusters formed, and then
they merged via gravity, resulting in larger star clusters.Comment: 4 pages, 3 figures, Proceedings of IAU Symposium 270, Computational
Star Formatio
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