title: Crossed spin-1/2 heisenberg chains as a quantum impurity problem.
abstract: Using equivalencies between different models we reduce the model of two spin-1/2 Heisenberg chains crossed at one point to the model of free fermions. The spin-spin correlation function is calculated by summing the perturbation series in the interchain interaction. The result reveals a power law decay with a nonuniversal exponent.
authors.affiliation: Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Reyes
authors.forename: A M
authors.initials: AM
authors.lastname: Tsvelik