6,323 research outputs found
The Anatomy of a Scientific Rumor
The announcement of the discovery of a Higgs boson-like particle at CERN will
be remembered as one of the milestones of the scientific endeavor of the 21st
century. In this paper we present a study of information spreading processes on
Twitter before, during and after the announcement of the discovery of a new
particle with the features of the elusive Higgs boson on 4th July 2012. We
report evidence for non-trivial spatio-temporal patterns in user activities at
individual and global level, such as tweeting, re-tweeting and replying to
existing tweets. We provide a possible explanation for the observed
time-varying dynamics of user activities during the spreading of this
scientific "rumor". We model the information spreading in the corresponding
network of individuals who posted a tweet related to the Higgs boson discovery.
Finally, we show that we are able to reproduce the global behavior of about
500,000 individuals with remarkable accuracy.Comment: 11 pages, 8 figure
Quantum marking and quantum erasure for neutral kaons
Entangled K0 anti-K0 pairs are shown to be suitable to discuss extensions and
tests of Bohr's complementarity principle through the quantum marking and
quantum erasure techniques suggested by M. O. Scully and K. Druehl [Phys. Rev.
A 25, 2208 (1982)]. Strangeness oscillations play the role of the traditional
interference pattern linked to wave-like behaviour, whereas the distinct
propagation in free space of the K_S and K_L components mimics the two possible
interferometric paths taken by particle-like objects.Comment: 4 RevTeX page
Theoretical analysis of aliasing noises in cold atom Mach-Zehnder interferometers
We present a theoretical analysis of aliasing noises that might appear in cold atom Mach-Zehnder interferometers used for the measurement of various physical quantities. We focus more specifically on single cold atom gyroscopes. To evaluate the level of aliasing noises, we have developed a model based on the power spectral densities of the different identified noise sources as input parameters and which makes use of a servo-loop to realize a precise measurement of the rotation rate. The model allows one to take into account different modes of operation, like a continuous as well as a pulsed or even a multi-ball operation. For monokinetic atoms, we show that the intermodulation noise can be completely filtered out with a continuous mode of operation and an optimum modulation scheme for any modulation frequency but also with a pulsed operation however only for specific launching frequencies. In the case of a real continuous atomic beam having a velocity distribution, it comes out that a high attenuation can be reached which indicates clearly the potential stability improvement that can be expected from a continuous operatio
Kaon physics with the KLOE detector
In this paper we discuss the recent finalized analyses by the KLOE experiment
at DANE: the CPT and Lorentz invariance test with entangled pairs, and the precision measurement of the branching fraction of
the decay . We also present the
status of an ongoing analysis aiming to precisely measure the mass
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Shake table testing of a tuned mass damper inerter (Tmdi)-equipped structure and nonlinear dynamic modeling under harmonic excitations
This paper presents preliminary experimental results from a novel shaking table testing campaign investigating the dynamic response of a two-degree-of-freedom (2DOF) physical specimen with a grounded inerter under harmonic base excitation and contributes a nonlinear dynamic model capturing the behavior of the test specimen. The latter consists of a primary mass connected to the ground through a high damping rubber isolator (HDRI) and a secondary mass connected to the primary mass through a second HDRI. Further, a flywheel-based rack-and-pinion inerter prototype device is used to connect the secondary mass to the ground. The resulting specimen resembles the tuned mass damper inerter (TMDI) configuration with grounded inerter analytically defined and numerically assessed by the authors in a number of previous publications. Physical specimens with three different inerter coefficients are tested on the shake table under sine-sweep excitation with three different amplitudes. Experimental frequency response functions (FRFs) are derived manifesting a softening nonlinear behavior of the specimens and enhanced vibration suppression with increased inerter coefficient. Further, a 2DOF parametric nonlinear model of the specimen is established accounting for non-ideal inerter device behavior and its potential to characterize experimental response time-histories, FRFs, and force-displacement relationships of the HDRIs and of the inerter is verified
Direct test of time-reversal symmetry in the entangled neutral kaon system at a -factory
We present a novel method to perform a direct T (time reversal) symmetry test
in the neutral kaon system, independent of any CP and/or CPT symmetry tests.
This is based on the comparison of suitable transition probabilities, where the
required interchange of in out states for a given process is obtained
exploiting the Einstein-Podolsky-Rosen correlations of neutral kaon pairs
produced at a -factory. In the time distribution between the two decays,
we compare a reference transition like the one defined by the time ordered
decays with the T -conjugated one defined by . With the use of this and other T conjugated comparisons, the KLOE-2
experiment at DANE could make a significant test
Strengthening of steel-reinforced concrete structural elements by externally bonded FRP sheets and evaluation of their load carrying capacity to face changed load service conditions
The paper has proposed a limit analysis procedure for a preliminary
design of RC elements strengthened by externally
bonded FRP sheets.
The procedure, based on a multi-yield-criteria limit analysis
approach, has led to a reliable prediction of peak loads and failure
modes of the analyzed elements (slabs) by simultaneously
considering the limit state of the constituent materials, so
resulting very useful in many applications of engineering
interest.
The attention has been focused on hospital applications in
which increment of service loads or realization of openings
can weaken some structural elements that have been strengthened
by FRP sheets
Phase transitions, double-scaling limit, and topological strings
Topological strings on Calabi--Yau manifolds are known to undergo phase
transitions at small distances. We study this issue in the case of perturbative
topological strings on local Calabi--Yau threefolds given by a bundle over a
two-sphere. This theory can be regarded as a q--deformation of Hurwitz theory,
and it has a conjectural nonperturbative description in terms of q--deformed 2d
Yang--Mills theory. We solve the planar model and find a phase transition at
small radius in the universality class of 2d gravity. We give strong evidence
that there is a double--scaled theory at the critical point whose all genus
free energy is governed by the Painlev\'e I equation. We compare the critical
behavior of the perturbative theory to the critical behavior of its
nonperturbative description, which belongs to the universality class of 2d
supergravity. We also give evidence for a new open/closed duality relating
these Calabi--Yau backgrounds to open strings with framing.Comment: 49 pages, 3 eps figures; section added on non-perturbative proposal
and 2d gravity; minor typos correcte
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