3 papers
math-ph2021
Dimerization in quantum spin chains with symmetry
Jakob E. Björnberg, Peter Mühlbacher, Bruno Nachtergaele +1
We consider quantum spins with , and two-body interactions with symmetry. We discuss the ground state phase diagram of the one-dimensional system. We give a rigor…
math-ph2018
Critical temperature of Heisenberg models on regular trees, via random loops
Jakob E. Björnberg, Daniel Ueltschi
We estimate the critical temperature of a family of quantum spin systems on regular trees of large degree. The systems include the spin- XXZ model and the spin-1 nematic m…
math.PR2012
Coexistence and non-coexistence of Markovian viruses and their hosts
Jakob E. Björnberg, Erik I. Broman
The possibility of coexistence of two competing populations is a classical question which dates back to the earliest `predator-prey' models. In this paper we study this question in…