In the present paper, we propose a mean field approach for spin ladders based upon the Jordan-Wigner transformation along an elaborately ordered path. We show on the mean field level that ladders with even number legs open a energy gap in their low energy excitation with a magnitude close to the corresponding experimental values, whereas the low energy excitation of the odd-number-leg ladders a...

The dynamic susceptibility χ Q (ω) of the isotropic XY-model (s=1/2) on the alternating superlattice (closed chain) in a transverse field h is obtained exactly at arbitrary temperatures. It is determined from the results obtained for the dynamic correlations < S jn(t)S z lm(0) >, which have been calculated by introducing the generalized Jordan-Wigner transformation, by using Wick’s theorem and ...

We investigate the spectral geometry of the exceptional Jordan algebra and its extensions. We examine the spectrum of the exceptional Jordan algebra over the sixteen-dimensional space of primitive idempotents, where it exhibits three real eigenvalues. We interpret the spectrum as coordinates for a coincident D-brane system where the real eigenvalues correspond to positions of three D0-branes on...

Pseudo-Riemannian manifolds of balanced signature which are both spacelike and timelike Jordan Osserman nilpotent of order 2 and of order 3 have been constructed previously. In this short note, we shall construct pseudo-Riemannian manifolds of signature (2s, s) for any s ≥ 2 which are spacelike Jordan Osserman nilpotent of order 3 but which are not timelike Jordan Osserman. Our example and tech...

1Department of Community and Family Medicine, University of Jordan, Amman, Jordan. 2Department of Health Policy and Management, Jordan University of Science and Technology, Irbid, Jordan. Received: 30/04/03; accepted: 26/10/03 ABSTRACT The study analysed time utilization by a sample of 111 physicians, nurses and midwives in 62 primary health care facilities in Jordan. The providers’ activity ov...

For several years, Jordan has been working in building and improving its e-government infra structure. As a result, there have been some improvements in the position of Jordan e-government relative to the worlds’ egovernments (according to some reports). However, some metrics and statistics about the online users do not indicate that there is a large percent of Jordanian citizens who are using ...

We study the symmetries of generalized spacetimes and corresponding phase spaces defined by Jordan algebras of degree three. The generic Jordan family of formally real Jordan algebras of degree three describe extensions of the Minkowskian spacetimes by an extra ”dilatonic” coordinate, whose rotation, Lorentz and conformal groups are SO(d−1), SO(d−1, 1)×SO(1, 1) and SO(d, 2)×SO(2, 1), respective...

We consider 3-Jordan algebras, i.e., the nonassociative commutative algebras satisfying (x^3 y)x=x^3(yx). The variety of 3-Jordan algebras contains all Jordan algebras and all pseudo-composition algebras. We prove that a simple 3-Jordan algebra with idempotent is either a Jordan algebra or a pseudo-composition algebra. Disciplines Algebra | Mathematics Comments This article is published as Hent...

There have been several propositions for a geometric and essentially non-linear formulation of quantum mechanics, see, e.g., [AS98], [BH01], [CGM03], [Ki79]. From a purely mathematical point of view, the point of view of Jordan algebra theory might give new strength to such approaches: there is a “Jordan geometry” belonging to the Jordan part of the algebra of observables, in the same way as Li...