18,341 research outputs found
Statistics and Quantum Chaos
We use multi-time correlation functions of quantum systems to construct
random variables with statistical properties that reflect the degree of
complexity of the underlying quantum dynamics.Comment: 12 pages, LateX, no figures, restructured versio
A conformal field theory description of the paired and parafermionic states in the quantum Hall effect
We extend the construction of the effective conformal field theory for the
Jain hierarchical fillings proposed in cond-mat/9912287 to the description of a
quantum Hall fluid at non standard fillings nu=m/(pm+2). The chiral primary
fields are found by using a procedure which induces twisted boundary conditions
on the m scalar fields; they appear as composite operators of a charged and
neutral component. The neutral modes describe parafermions and contribute to
the ground state wave function with a generalized Pfaffian term. Correlators of
Ne electrons in the presence of quasi-hole excitations are explicitly given for
m=2.Comment: 11 pages, plain Late
Clustering Boolean Tensors
Tensor factorizations are computationally hard problems, and in particular,
are often significantly harder than their matrix counterparts. In case of
Boolean tensor factorizations -- where the input tensor and all the factors are
required to be binary and we use Boolean algebra -- much of that hardness comes
from the possibility of overlapping components. Yet, in many applications we
are perfectly happy to partition at least one of the modes. In this paper we
investigate what consequences does this partitioning have on the computational
complexity of the Boolean tensor factorizations and present a new algorithm for
the resulting clustering problem. This algorithm can alternatively be seen as a
particularly regularized clustering algorithm that can handle extremely
high-dimensional observations. We analyse our algorithms with the goal of
maximizing the similarity and argue that this is more meaningful than
minimizing the dissimilarity. As a by-product we obtain a PTAS and an efficient
0.828-approximation algorithm for rank-1 binary factorizations. Our algorithm
for Boolean tensor clustering achieves high scalability, high similarity, and
good generalization to unseen data with both synthetic and real-world data
sets
The relationship between IR and multimedia databases
Modern extensible database systems support multimedia data through ADTs. However, because of the problems with multimedia query formulation, this support is not sufficient.\ud
\ud
Multimedia querying requires an iterative search process involving many different representations of the objects in the database. The support that is needed is very similar to the processes in information retrieval.\ud
\ud
Based on this observation, we develop the miRRor architecture for multimedia query processing. We design a layered framework based on information retrieval techniques, to provide a usable query interface to the multimedia database.\ud
\ud
First, we introduce a concept layer to enable reasoning over low-level concepts in the database.\ud
\ud
Second, we add an evidential reasoning layer as an intermediate between the user and the concept layer.\ud
\ud
Third, we add the functionality to process the users' relevance feedback.\ud
\ud
We then adapt the inference network model from text retrieval to an evidential reasoning model for multimedia query processing.\ud
\ud
We conclude with an outline for implementation of miRRor on top of the Monet extensible database system
Anyons as quon particles
The momentum operator representation of nonrelativistic anyons is developed
in the Chern - Simons formulation of fractional statistics. The connection
between anyons and the q-deformed bosonic algebra is established.Comment: 10 pages,Late
Measuring Multijet Structure of Hadronic Energy Flow Or What IS A Jet?
Ambiguities of jet algorithms are reinterpreted as instability wrt small
variations of input. Optimal stability occurs for observables possessing
property of calorimetric continuity (C-continuity) predetermined by kinematical
structure of calorimetric detectors. The so-called C-correlators form a basic
class of such observables and fit naturally into QFT framework, allowing
systematic theoretical studies. A few rules generate other C-continuous
observables. The resulting C-algebra correctly quantifies any feature of
multijet structure such as the "number of jets" and mass spectra of "multijet
substates". The new observables are physically equivalent to traditional ones
but can be computed from final states bypassing jet algorithms which reemerge
as a tool of approximate computation of C-observables from data with all
ambiguities under analytical control and an optimal recombination criterion
minimizing approximation errors.Comment: PostScript, 94 pp (US Letter), 18 PS files, [email protected]
- …