531,355 research outputs found
On the significance of a recent experiment demonstrating quantum interference in time
I comment on the interpretation of a recent experiment showing quantum
interference in time. It is pointed out that the standard nonrelativistic
quantum theory, used by the authors in their analysis, cannot account for the
results found, and therefore that this experiment has fundamental importance
beyond the technical advances it represents. Some theoretical structures which
consider the time as an observable, and thus could, in principle, have the
required coherence in time, are discussed briefly, and the application of
Floquet theory and the manifestly covariant quantum theory of Stueckelberg are
treated in some detail. In particular, the latter is shown to account for the
results in a simple and consistent way.Comment: 10 pages, plain TeX. Revision for clarity, reference to other
candidate theorie
Quantum Hall States of High Symmetry
We identify some hidden symmetries of Chern-Simons theories, such as appear
in the effective theory for quantized Hall states. This allows us to determine
which filling fractions admit spin-singlet quantum Hall states. Our results
shed some light on states already observed at , and transitions
between them. We identify SU(2), or higher, symmetries of many additional
states -- including spin-polarized states. Our symmetries classify low-lying
excited states and may be of use in the construction of trial wavefunctions,
but are typically not present in the edge theory, where they are lifted by
non-universal couplings.Comment: 17 pages, PostScript, 1 figure included. Revision - corrected slight
error in equation (3.5) on Page
General Argyres-Douglas Theory
We construct a large class of Argyres-Douglas type theories by compactifying
six dimensional (2,0) A_N theory on a Riemann surface with irregular
singularities. We give a complete classification for the choices of Riemann
surface and the singularities. The Seiberg-Witten curve and scaling dimensions
of the operator spectrum are worked out. Three dimensional mirror theory and
the central charges a and c are also calculated for some subsets, etc. Our
results greatly enlarge the landscape of N=2 superconformal field theory and in
fact also include previous theories constructed using regular singularity on
the sphere.Comment: 55 pages, 20 figures, minor revision and typos correcte
Topological Andr\'e-Quillen homology for cellular commutative -algebras
Topological Andr\'e-Quillen homology for commutative -algebras was
introduced by Basterra following work of Kriz, and has been intensively studied
by several authors. In this paper we discuss it as a homology theory on CW
-algebras and apply it to obtain results on minimal atomic -local
-algebras which generalise those of Baker and May for -local spectra and
simply connected spaces. We exhibit some new examples of minimal atomic
-algebras.Comment: Final revision, a version will appear in Abhandlungen aus dem
Mathematischen Seminar der Universitaet Hambur
Induced aggregation operators in decision making with the Dempster-Shafer belief structure
We study the induced aggregation operators. The analysis begins with a revision of some basic concepts such as the induced ordered weighted averaging (IOWA) operator and the induced ordered weighted geometric (IOWG) operator. We then analyze the problem of decision making with Dempster-Shafer theory of evidence. We suggest the use of induced aggregation operators in decision making with Dempster-Shafer theory. We focus on the aggregation step and examine some of its main properties, including the distinction between descending and ascending orders and different families of induced operators. Finally, we present an illustrative example in which the results obtained using different types of aggregation operators can be seen.aggregation operators, dempster-shafer belief structure, uncertainty, iowa operator, decision making
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