6,241 research outputs found
The Flatness of Mass-to-Light Ratio on Large Scales
It has been suggested that the mass-to-light () ratio of gravitationally
clustering objects is scale-independent on scales beyond galaxy clusters, and
may also be independent of the mass of the objects. In this paper, we show that
the scale behavior of ratio is closely related to the scaling of cosmic
structures larger than clusters. The scale dependence of the ratio can be
determined by comparing the observed scaling of richness function (RF) of
multi-scale identified objects with the model-predicted scaling of mass
function (MF) of large scale structures. Using the multi-scale identified
clusters from IRAS 1.2 Jy galaxy survey, we have made comparisons of the
observed RF scaling of IRAS -clusters with the MF scalings given by
simulations of three popular models SCDM, LCDM and OCDM. We find that, the M/L
ratio basically is scale-independent from the Abell radius up to about 24
Mpc, while it seems to show a slight, but systematical, increase over
this scale range. This result is weakly dependent on the cosmological
parameters.Comment: AAS Latex file, 8 pages+ 4 figures, accepted for publication in ApJ
Tunneling Qubit Operation on a Protected Josephson Junction Array
We discuss a protected quantum computation process based on a hexagon
Josephson junction array. Qubits are encoded in the punctured array, which is
topologically protected. The degeneracy is related to the number of holes. The
topological degeneracy is lightly shifted by tuning the flux through specific
hexagons. We also show how to perform single qubit operation and basic quantum
gate operations in this system.Comment: 8 pages, 4 figures. The published version in Phys. Rev.,
A81(2010)01232
On the exactness of soft theorems
Soft behaviours of S-matrix for massless theories reflect the underlying
symmetry principle that enforces its masslessness. As an expansion in soft
momenta, sub-leading soft theorems can arise either due to (I) unique structure
of the fundamental vertex or (II) presence of enhanced broken-symmetries. While
the former is expected to be modified by infrared or ultraviolet divergences,
the latter should remain exact to all orders in perturbation theory. Using
current algebra, we clarify such distinction for spontaneously broken (super)
Poincar\'e and (super) conformal symmetry. We compute the UV divergences of
DBI, conformal DBI, and A-V theory to verify the exactness of type (II) soft
theorems, while type (I) are shown to be broken and the soft-modifying
higher-dimensional operators are identified. As further evidence for the
exactness of type (II) soft theorems, we consider the alpha' expansion of both
super and bosonic open strings amplitudes, and verify the validity of the
translation symmetry breaking soft-theorems up to O(alpha'^6). Thus the
massless S-matrix of string theory "knows" about the presence of D-branes.Comment: 35 pages. Additional mathematica note book with the UV-divergenece of
the 6-point amplitude in AV/KS theor
JALAD: Joint Accuracy- and Latency-Aware Deep Structure Decoupling for Edge-Cloud Execution
Recent years have witnessed a rapid growth of deep-network based services and
applications. A practical and critical problem thus has emerged: how to
effectively deploy the deep neural network models such that they can be
executed efficiently. Conventional cloud-based approaches usually run the deep
models in data center servers, causing large latency because a significant
amount of data has to be transferred from the edge of network to the data
center. In this paper, we propose JALAD, a joint accuracy- and latency-aware
execution framework, which decouples a deep neural network so that a part of it
will run at edge devices and the other part inside the conventional cloud,
while only a minimum amount of data has to be transferred between them. Though
the idea seems straightforward, we are facing challenges including i) how to
find the best partition of a deep structure; ii) how to deploy the component at
an edge device that only has limited computation power; and iii) how to
minimize the overall execution latency. Our answers to these questions are a
set of strategies in JALAD, including 1) A normalization based in-layer data
compression strategy by jointly considering compression rate and model
accuracy; 2) A latency-aware deep decoupling strategy to minimize the overall
execution latency; and 3) An edge-cloud structure adaptation strategy that
dynamically changes the decoupling for different network conditions.
Experiments demonstrate that our solution can significantly reduce the
execution latency: it speeds up the overall inference execution with a
guaranteed model accuracy loss.Comment: conference, copyright transfered to IEE
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