128 citations · 793 across the 55 of their papers we have counts for
56 papers
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…
Thermodynamics of the spin square
Heinz-Jürgen Schmidt, Christian Schröder
Small spin systems at the interface between analytical studies and experimental application have been intensively studied in recent decades. The spin ring consisting of four spins…
Classical ground states of spin lattices
Heinz-Jürgen Schmidt, Johannes Richter
We present a generalization of the Luttinger-Tisza-Lyons-Kaplan (LTLK) theory of classical ground states of Bravais lattices with Heisenberg coupling to non-Bravais lattices. It co…
Thermodynamics of the classical spin triangle
Heinz-Jürgen Schmidt, Christian Schröder
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 th…
Einstein's photon box revisited
Heinz-Jürgen Schmidt
We present a reformulation of Bohr's analysis of Einstein's thought experiment with the photon box, which hopefully settles some unclear issues. The box is weighed by two position…
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…