Quantum integrability in two-dimensional systems with boundary

In this paper we consider affine Toda systems defined on the half-plane and study the issue of integrability, i.e. the construction of higher-spin conserved currents in the presence of a boundary perturbation. First at the classical level we formulate the problem within a Lax pair approach which allows to determine the general structure of the boundary perturbation compatible with integrability. Then we analyze the situation at the quantum level and compute corrections to the classical conservation laws in specific examples. We find that, except for the sinh-Gordon model, the existence of quantum conserved currents requires a finite renormalization of the boundary potential.Comment: latex file, 18 pages, 1 figur

Magnetic Field Behaviour of a Haldane Gap Antiferromagnet

We investigate the magnetic field behaviour of an antiferromagnetic Heisenberg spin-1 chain with the most general single-ion anisotropy. We discuss the regime in which the magnetic field is below the transition value. The splitting of the Haldane triplet is obtained as a function of a field applied in an arbitrary orientation by means of a Lancz\H os exact diagonalization of chains of up to 16 spins. Our results are nicely summarized in terms of a first-order perturbation theory. We explain various level crossings that occur by the existence of discrete symmetries. A discussion is given of the electron spin resonance and neutron scattering experiments on the compound Ni(C$_2$H$_8$N$_2$)$_2$NO$_2$ClO$_4$ (NENP).Comment: 18 pages and 6 figs not included available by ftp, plain TeX, SPhT/93-04

Cutting Edge Technology Metros in the Mountain West, 2021

This fact sheet highlights data on cutting-edge technology metros in the Mountain West, as originally reported in the Commercial Cafe report, “Boulder Tops Silicon Valley as Most Cutting-Edge Metro in the U.S.” Of the top 30 cutting-edge metros in the nation, four are in the Mountain West: Boulder, CO (1st nationally); Denver, CO (7th nationally); Salt Lake City, UT (10th nationally); and Phoenix, AZ (27th nationally)

Foster Youth in the Mountain West

This fact sheet examines population trends for foster youth and their experiences with foster care in the Mountain West region. The data are sourced from the report “State-level Data for Understanding Child Welfare in the United States” which cites the National Data Archive on Child Abuse and Neglect (NDACAN) for fiscal year (FY) 2020 and the “State-by State Data” report by the Casey Family Programs from FY 2020. This fact sheet highlights the number of foster youth in the Mountain West (Arizona, Colorado, Nevada, New Mexico, and Utah) and their demographic composition

Health Rankings: Mountain West States, 2021

Using data from the United Health Foundation’s “America’s Health Rankings Annual Report 2021,” this fact sheet compares various measures of health in the Mountain West using data from 2014 to 2021. The original report includes data on the five determinants of health including social and economic factors, physical environment, clinical care, behaviors, and health outcomes. This fact sheet examines health metrics for the Mountain West states of Arizona, Colorado, Nevada, New Mexico, and Utah