26 research outputs found
Pilot VLBI Survey of SiO v=3 J=1--0 Maser Emission around Evolved Stars
In this Letter, we report detections of SiO v=3 J=1--0 maser emission in very
long baseline interferometric (VLBI) observations towards 4 out of 12
long-period variable stars: WX Psc, R Leo, W Hya, and T Cep. The detections
towards WX Psc and T Cep are new ones. We also present successful astrometric
observations of SiO v=2 and v=3 J=1--0 maser emissions associated with two
stars: WX Psc and W Hya and their position-reference continuum sources:
J010746.0+131205 and J135146.8-291218 with the VLBI Exploration of Radio
Astrometry (VERA). The relative coordinates of the position-reference continuum
source and SiO v=3 maser spots were measured with respect to those of an SiO
v=2 maser spot adopted as fringe-phase reference. Thus the faint continuum
sources were inversely phase-referenced to the bright maser sources. It implies
possible registration of multiple SiO maser line maps onto a common coordinate
system with 10 microarcsecond-level accuracy.Comment: 5 Pages, 3 figures, Fig.3 and Tab. 2 were corrected; Publications of
the Astronomical Society of Japan, Vol. 64, No. 6 issued on 2012 December 2
A Quantum Internet Architecture
Entangled quantum communication is advancing rapidly, with laboratory and
metropolitan testbeds under development, but to date there is no unifying
Quantum Internet architecture. We propose a Quantum Internet architecture
centered around the Quantum Recursive Network Architecture (QRNA), using
RuleSet-based connections established using a two-pass connection setup.
Scalability and internetworking (for both technological and administrative
boundaries) are achieved using recursion in naming and connection control. In
the near term, this architecture will support end-to-end, two-party
entanglement on minimal hardware, and it will extend smoothly to multi-party
entanglement and the use of quantum error correction on advanced hardware in
the future. For a network internal gateway protocol, we recommend (but do not
require) qDijkstra with seconds per Bell pair as link cost for routing; the
external gateway protocol is designed to build recursively. The strength of our
architecture is shown by assessing extensibility and demonstrating how robust
protocol operation can be confirmed using the RuleSet paradigm.Comment: 17 pages, 7 numbered figure
QuISP: a Quantum Internet Simulation Package
We present an event-driven simulation package called QuISP for large-scale
quantum networks built on top of the OMNeT++ discrete event simulation
framework. Although the behavior of quantum networking devices have been
revealed by recent research, it is still an open question how they will work in
networks of a practical size. QuISP is designed to simulate large-scale quantum
networks to investigate their behavior under realistic, noisy and heterogeneous
configurations. The protocol architecture we propose enables studies of
different choices for error management and other key decisions. Our confidence
in the simulator is supported by comparing its output to analytic results for a
small network. A key reason for simulation is to look for emergent behavior
when large numbers of individually characterized devices are combined. QuISP
can handle thousands of qubits in dozens of nodes on a laptop computer,
preparing for full Quantum Internet simulation. This simulator promotes the
development of protocols for larger and more complex quantum networks.Comment: 17 pages, 12 figure