15,096 research outputs found
Evolution of the Chern-Simons Vortices
Based on the gauge potential decomposition theory and the -mapping
theory, the topological inner structure of the Chern-Simons-Higgs vortex has
been showed in detail. The evolution of CSH vortices is studied from the
topological properties of the Higgs scalar field. The vortices are found
generating or annihilating at the limit points and encountering, splitting or
merging at the bifurcation points of the scalar field Comment: 10 pages, 10 figure
Neutrinos, Weak Interactions, and r-process Nucleosynthesis
Two of the key issues in understanding the neutron-to-proton ratio in a
core-collapse supernova are discussed. One of these is the behavior of the
neutrino-nucleon cross sections as supernova energies. The other issue is the
many-body properties of the neutrino gas near the core when both one- and
two-body interaction terms are included.Comment: To be published in the Proceedings of "International Symposium on
Structure of Exotic Nuclei and Nuclear Forces (SENUF 06)", March 2006, Tokyo,
Japa
Quantum State Separation, Unambiguous Discrimination and Exact Cloning
Unambiguous discrimination and exact cloning reduce the square-overlap
between quantum states, exemplifying the more general type of procedure we term
state separation. We obtain the maximum probability with which two equiprobable
quantum states can be separated by an arbitrary degree, and find that the
established bounds on the success probabilities for discrimination and cloning
are special cases of this general bound. The latter also gives the maximum
probability of successfully producing N exact copies of a quantum system whose
state is chosen secretly from a known pair, given M initial realisations of the
state, where N>M. We also discuss the relationship between this bound and that
on unambiguous state discrimination.Comment: RevTeX, 5 pages postscrip
Identifying Retweetable Tweets with a Personalized Global Classifier
In this paper we present a method to identify tweets that a user may find
interesting enough to retweet. The method is based on a global, but
personalized classifier, which is trained on data from several users,
represented in terms of user-specific features. Thus, the method is trained on
a sufficient volume of data, while also being able to make personalized
decisions, i.e., the same post received by two different users may lead to
different classification decisions. Experimenting with a collection of approx.\
130K tweets received by 122 journalists, we train a logistic regression
classifier, using a wide variety of features: the content of each tweet, its
novelty, its text similarity to tweets previously posted or retweeted by the
recipient or sender of the tweet, the network influence of the author and
sender, and their past interactions. Our system obtains F1 approx. 0.9 using
only 10 features and 5K training instances.Comment: This is a long paper version of the extended abstract titled "A
Personalized Global Filter To Predict Retweets", of the same authors, which
was published in the 25th ACM UMAP conference in Bratislava, Slovakia, in
July 201
Entanglement of two atomic samples by quantum non-demolition measurements
This paper presents simulations of the state vector dynamics for a pair of
atomic samples which are being probed by phase shift measurements on an optical
beam passing through both samples. We show how measurements, which are
sensitive to different atomic components, serve to prepare states which are
close to being maximally entangled.Comment: 8 pages, 8 figures, REVTeX
Effects of Dissipation on Quantum Phase Slippage in Charge Density Wave Systems
We study the effect of the dissipation on the quantum phase slippage via the
creation of ``vortex ring'' in charge density wave (CDW) systems. The
dissipation is assumed to come from the interaction with the normal electron
near and inside of the vortex core. We describe the CDW by extracted
macroscopic degrees of freedom, that is, the CDW phase and the radius of the
``vortex ring'', assume the ohmic dissipation, and investigate the effect in
the context of semiclassical approximation.
The obtained results are discussed in comparison with experiments. It turns
out that the effect of such a dissipation can be neglected in experiments.Comment: 9 pages (revtex), 2 figures, using epsf.st
Quantum Interference of Photon Pairs from Two Trapped Atomic Ions
We collect the fluorescence from two trapped atomic ions, and measure quantum
interference between photons emitted from the ions. The interference of two
photons is a crucial component of schemes to entangle atomic qubits based on a
photonic coupling. The ability to preserve the generated entanglement and to
repeat the experiment with the same ions is necessary to implement entangling
quantum gates between atomic qubits, and allows the implementation of protocols
to efficiently scale to larger numbers of atomic qubits.Comment: 4 pages, 4 figure
- …