37,450 research outputs found
The nature of obscuration in AGN: II. insights from clustering properties
Based on large optical and mid-infrared (IR) surveys, we investigate the
relation between nuclear activity in local Seyfert 2 galaxies and galaxy
interactions using a statistical neighbour counting technique. At the same
level of host galaxy star formation (SF), we find that active galactic nuclei
(AGNs) with stronger [OIII] emission lines do not show an excess of near
neighbours, while AGNs with stronger mid-IR emission do have more near
neighbours within a projected distance of 100 kpc. The excess neighbour count
increases with decreasing projected radius. These results suggest a phase of
torus formation during galaxy interactions.Comment: 5 pages, 2 figures, accepted to MNRA
Efficient Subgraph Matching on Billion Node Graphs
The ability to handle large scale graph data is crucial to an increasing
number of applications. Much work has been dedicated to supporting basic graph
operations such as subgraph matching, reachability, regular expression
matching, etc. In many cases, graph indices are employed to speed up query
processing. Typically, most indices require either super-linear indexing time
or super-linear indexing space. Unfortunately, for very large graphs,
super-linear approaches are almost always infeasible. In this paper, we study
the problem of subgraph matching on billion-node graphs. We present a novel
algorithm that supports efficient subgraph matching for graphs deployed on a
distributed memory store. Instead of relying on super-linear indices, we use
efficient graph exploration and massive parallel computing for query
processing. Our experimental results demonstrate the feasibility of performing
subgraph matching on web-scale graph data.Comment: VLDB201
Quantum discord and geometry for a class of two-qubit states
We study the level surfaces of quantum discord for a class of two-qubit
states with parallel nonzero Bloch vectors. The dynamic behavior of quantum
discord under decoherence is investigated. It is shown that a class of X states
has sudden transition between classical and quantum correlations under
decoherence. Our results include the ones in M. D. Lang and C. M. Caves [Phys.
Rev. Lett. 105, 150501 (2010)] as a special case and show new pictures and
structures of quantum discord.Comment: 5 pages, 5 figure
Soft gluon resummation in the signal-background interference process of
We present a precise theoretical prediction for the signal-background
interference process of , which is useful to constrain the
Higgs boson decay width and to measure Higgs couplings to the SM particles. The
approximate NNLO -factor is in the range of (),
depending on , at the 8 (13) TeV LHC. And the soft gluon resummation
can increase the approximate NNLO result by about at both the 8 TeV and
13 TeV LHC. The theoretical uncertainties including the scale, uncalculated
multi-loop amplitudes of the background and PDF are roughly
at . We also confirm that the approximate
-factors in the interference and the pure signal processes are the same.Comment: 18 pages, 9 figures; v2 published in JHE
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