18,278 research outputs found
Hadron Systematics and Emergent Diquarks
We briefly review a variety of theoretical and phenomenological indications
for the probable importance of powerful diquark correlations in hadronic
physics. We demonstrate that the bulk of light hadron spectroscopy can be
organized using three simple hypotheses: Regge-Chew-Frautschi mass formulae,
feebleness of spin-orbit forces, and energetic distinctions among a few
different diquark configurations. Those hypotheses can be implemented in a
semi-classical model of color flux tubes, extrapolated down from large orbital
angular momentum . We discuss refinements of the model to include the
effects of tunneling, mass loading, and internal excitations. We also discern
effects of diquark correlations in observed patterns of baryon decays. Many
predictions and suggestions for further work appear.Comment: 18 pages, 11 figures. Talk by FW at a workshop at Schloss Ringberg,
October 2005. To appear in the Proceeding
A note on the Bethe ansatz solution of the supersymmetric t-J model
The three different sets of Bethe ansatz equations describing the Bethe
ansatz solution of the supersymmetric t-J model are known to be equivalent.
Here we give a new, simplified proof of this fact which relies on the
properties of certain polynomials. We also show that the corresponding transfer
matrix eigenvalues agree.Comment: 6 pages, Latex, contributed to the 12th Int. Colloquium on Quantum
Groups and Integrable Systems, Prague, 200
The spectral density of a product of spectral projections
We consider the product of spectral projections where and are the free and the
perturbed Schr\"odinger operators with a short range potential, is
fixed and . We compute the leading term of the asymptotics of
as for continuous
functions vanishing sufficiently fast near zero. Our construction
elucidates calculations that appeared earlier in the theory of "Anderson's
orthogonality catastrophe" and emphasizes the role of Hankel operators in this
phenomenon.Comment: 23 pages; minor revision
Kato smoothness and functions of perturbed self-adjoint operators
We consider the difference for self-adjoint operators
and acting in a Hilbert space. We establish a new class of estimates for
the operator norm and the Schatten class norms of this difference. Our
estimates utilise ideas of scattering theory and involve conditions on
and in terms of the Kato smoothness. They allow for a much wider class of
functions (including some unbounded ones) than previously available results
do. As an important technical tool, we propose a new notion of Schatten class
valued smoothness and develop a new framework for double operator integrals
K. Saito's Conjecture for Nonnegative Eta Products and Analogous Results for Other Infinite Products
We prove that the Fourier coefficients of a certain general eta product
considered by K. Saito are nonnegative. The proof is elementary and depends on
a multidimensional theta function identity. The z=1 case is an identity for the
generating function for p-cores due to Klyachko [17] and Garvan, Kim and
Stanton [10]. A number of other infinite products are shown to have nonnegative
coefficients. In the process a new generalization of the quintuple product
identity is derived.Comment: 15 pages; greatly expanded version of the earlier 8 page paper
math.NT/060760
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