10,444 research outputs found
On the Spectrum of Wenger Graphs
Let , where is a prime and is an integer. For ,
let and be two copies of the -dimensional vector spaces over the
finite field . Consider the bipartite graph with partite
sets and defined as follows: a point is adjacent to a line if and only if the
following equalities hold: for . We call the graphs Wenger graphs. In this paper, we determine all
distinct eigenvalues of the adjacency matrix of and their
multiplicities. We also survey results on Wenger graphs.Comment: 9 pages; accepted for publication to J. Combin. Theory, Series
Disconnecting strongly regular graphs
In this paper, we show that the minimum number of vertices whose removal
disconnects a connected strongly regular graph into non-singleton components,
equals the size of the neighborhood of an edge for many graphs. These include
blocks graphs of Steiner -designs, many Latin square graphs and strongly
regular graphs whose intersection parameters are at most a quarter of their
valency
Phonon nanocapacitor for storage and lasing of terahertz lattice waves
We introduce a novel ultra-compact nanocapacitor of coherent phonons formed
by high-finesse interference mirrors based on atomic-scale semiconductor
metamaterials. Our molecular dynamics simulations show that the nanocapacitor
stores THz monochromatic lattice waves, which can be used for phonon lasing -
the emission of coherent phonons. Either one- or two-color phonon lasing can be
realized depending on the geometry of the nanodevice. The two color regimes of
the capacitor originates from the distinct transmittance dependance on the
phonon wave packet incident angle for the two phonon polarizations at their
respective resonances. Phonon nanocapacitor can be charged by cooling the
sample equilibrated at room temperature or by the pump-probe technique. The
nanocapacitor can be discharged by applying tunable reversible strain,
resulting in the emission of coherent THz acoustic beams.Comment: 12 pages, 5 figure
Solving the TTC 2011 Compiler Optimization Case with QVTR-XSLT
In this short paper we present our solution for the Compiler Optimization
case study of the Transformation Tool Contest (TTC) 2011 using the QVTR-XSLT
tool. The tool supports editing and execution of the graphical notation of QVT
Relations languageComment: In Proceedings TTC 2011, arXiv:1111.440
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