810 research outputs found
Noncommmutative theorems: Gelfand Duality, Spectral, Invariant Subspace, and Pontryagin Duality
We extend the Gelfand-Naimark duality of commutative C*-algebras, "A
COMMUTATIVE C*-ALGEBRA -- A LOCALLY COMPACT HAUSDORFF SPACE" to "A
C*-ALGEBRA--A QUOTIENT OF A LOCALLY COMPACT HAUSDORFF SPACE". Thus, a
C*-algebra is isomorphic to the convolution algebra of continuous regular Borel
measures on the topological equivalence relation given by the above mentioned
quotient. In commutative case this reduces to Gelfand-Naimark theorem.
Applications: 1) A simultaneous extension, to arbitrary Hilbert space
operators, of Jordan Canonical Form and Spectral Theorem of normal operators 2)
A functional calculus for arbitrary operators. 3) Affirmative solution of
Invariant Subspace Problem. 4) Extension of Pontryagin duality to nonabelian
groups, and inevitably to groups whose underlying topological space is
noncommutative.Comment: 10 page
Theory of Multiband Superconductivity in Iron Pnictides
The precise nature of unconventional superconductivity in Iron Pnictides is
presently a hotly debated issue. Here, using insights from normal state
electronic structure and symmetry arguments, we show how an unconventional SC
emerges from the bad metal "normal" state. Short-ranged, multi-band spin- and
charge correlations generates nodeless SC in the active planar
bands, and an inter-band proximity effect induces out-of-plane gap nodes in the
passive band. While very good quantitative agreement with
various key observations in the SC state and reconciliation with NMR and
penetration depth data in the same picture are particularly attractive features
of our proposal, clinching evidence would be an experimental confirmation of
c-axis nodes in future work.Comment: 4 pages, 2 eps figures, submitted to PRL, text modifie
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