128 citations · 793 across the 55 of their papers we have counts for
5 papers · 1 filter
Classical limit of Gibbs states for quantum spin systems
Heinz-Jürgen Schmidt
We study the relation between quantum mechanical and classical Gibbs states of spin systems with spin quantum number . It is known that quantum states and observables can be rep…
The classical spin triangle as an integrable system
Heinz-Jürgen Schmidt
The classical spin system consisting of three spins with Heisenberg interaction is an example of a completely integrable mechanical system. In this paper we explicitly calculate it…
Dilation of stochastic matrices by coarse graining
Heinz-Jürgen Schmidt
We consider two different ways of representing stochastic matrices by bi-stochastic ones acting on a larger probability space, referred to as ``dilation by uniform coarse graining"…
Classes of integrable spin systems
Robin Steinigeweg, Heinz-Jürgen Schmidt
We investigate certain classes of integrable classical or quantum spin systems. The first class is characterized by the recursively defined property saying that the spin system…
On cyclically shifted strings
K. Baerwinkel, H. -J. Schmidt, J. Schnack
If a string is cyclically shifted it will re-appear after a certain number of shifts, which will be called its order. We solve the problem of how many strings exist with a given or…