86,724 research outputs found
SU(3)-Goodman-de la Harpe-Jones subfactors and the realisation of SU(3) modular invariants
We complete the realisation by braided subfactors, announced by Ocneanu, of
all SU(3)-modular invariant partition functions previously classified by
Gannon.Comment: 47 pages, minor changes, to appear in Reviews in Mathematical Physic
In-flight friction and wear mechanism
A unique mechanism developed for conducting friction and wear experiments in orbit is described. The device is capable of testing twelve material samples simultaneously. Parameters considered critical include: power, weight, volume, mounting, cleanliness, and thermal designs. The device performed flawlessly in orbit over an eighteen month period and demonstrated the usefulness of this design for future unmanned spacecraft or shuttle applications
Modular invariants from subfactors
In these lectures we explain the intimate relationship between modular
invariants in conformal field theory and braided subfactors in operator
algebras. A subfactor with a braiding determines a matrix which is obtained
as a coupling matrix comparing two kinds of braided sector induction
("alpha-induction"). It has non-negative integer entries, is normalized and
commutes with the S- and T-matrices arising from the braiding. Thus it is a
physical modular invariant in the usual sense of rational conformal field
theory. The algebraic treatment of conformal field theory models, e.g.
models, produces subfactors which realize their known modular
invariants. Several properties of modular invariants have so far been noticed
empirically and considered mysterious such as their intimate relationship to
graphs, as for example the A-D-E classification for . In the subfactor
context these properties can be rigorously derived in a very general setting.
Moreover the fusion rule isomorphism for maximally extended chiral algebras due
to Moore-Seiberg, Dijkgraaf-Verlinde finds a clear and very general proof and
interpretation through intermediate subfactors, not even referring to
modularity of and . Finally we give an overview on the current state of
affairs concerning the relations between the classifications of braided
subfactors and two-dimensional conformal field theories. We demonstrate in
particular how to realize twisted (type II) descendant modular invariants of
conformal inclusions from subfactors and illustrate the method by new examples.Comment: Typos corrected and a few minor changes, 37 pages, AMS LaTeX, epic,
eepic, doc-class conm-p-l.cl
Modular invariants and subfactors
In this lecture we explain the intimate relationship between modular
invariants in conformal field theory and braided subfactors in operator
algebras. Our analysis is based on an approach to modular invariants using
braided sector induction ("-induction") arising from the treatment of
conformal field theory in the Doplicher-Haag-Roberts framework. Many properties
of modular invariants which have so far been noticed empirically and considered
mysterious can be rigorously derived in a very general setting in the subfactor
context. For example, the connection between modular invariants and graphs (cf.
the A-D-E classification for ) finds a natural explanation and
interpretation. We try to give an overview on the current state of affairs
concerning the expected equivalence between the classifications of braided
subfactors and modular invariant two-dimensional conformal field theories.Comment: 25 pages, AMS LaTeX, epic, eepic, doc-class fic-1.cl
Modular Invariants, Graphs and -Induction for Nets of Subfactors I
We analyze the induction and restriction of sectors for nets of subfactors
defined by Longo and Rehren. Picking a local subfactor we derive a formula
which specifies the structure of the induced sectors in terms of the original
DHR sectors of the smaller net and canonical endomorphisms. We also obtain a
reciprocity formula for induction and restriction of sectors, and we prove a
certain homomorphism property of the induction mapping.
Developing further some ideas of F. Xu we will apply this theory in a
forthcoming paper to nets of subfactors arising from conformal field theory, in
particular those coming from conformal embeddings or orbifold inclusions of
SU(n) WZW models. This will provide a better understanding of the labeling of
modular invariants by certain graphs, in particular of the A-D-E classification
of SU(2) modular invariants.Comment: 36 pages, latex, several corrections, a strong additivity assumption
had to be adde
Modular Invariants from Subfactors: Type I Coupling Matrices and Intermediate Subfactors
A braided subfactor determines a coupling matrix Z which commutes with the S-
and T-matrices arising from the braiding. Such a coupling matrix is not
necessarily of "type I", i.e. in general it does not have a block-diagonal
structure which can be reinterpreted as the diagonal coupling matrix with
respect to a suitable extension. We show that there are always two intermediate
subfactors which correspond to left and right maximal extensions and which
determine "parent" coupling matrices Z^\pm of type I. Moreover it is shown that
if the intermediate subfactors coincide, so that Z^+=Z^-, then Z is related to
Z^+ by an automorphism of the extended fusion rules. The intertwining relations
of chiral branching coefficients between original and extended S- and
T-matrices are also clarified. None of our results depends on non-degeneracy of
the braiding, i.e. the S- and T-matrices need not be modular. Examples from
SO(n) current algebra models illustrate that the parents can be different,
Z^+\neq Z^-, and that Z need not be related to a type I invariant by such an
automorphism.Comment: 25 pages, latex, a new Lemma 6.2 added to complete an argument in the
proof of the following lemma, minor changes otherwis
Rules for transition rates in nonequilibrium steady states
Just as transition rates in a canonical ensemble must respect the principle
of detailed balance, constraints exist on transition rates in driven steady
states. I derive those constraints, by maximum information-entropy inference,
and apply them to the steady states of driven diffusion and a sheared lattice
fluid. The resulting ensemble can potentially explain nonequilibrium phase
behaviour and, for steady shear, gives rise to stress-mediated long-range
interactions.Comment: 4 pages. To appear in Physical Review Letter
Random access-random release relay switching matrix
XY relay switching matrix provides complete random access and random release of 400 points. A mercury-wetted bistable relay with independent set and reset coils is the unique feature associated with each point
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