75 citations · 128 across the 14 of their papers we have counts for
15 papers
Quantum orientation, Noether structure, composition of systems and operations
Heinz-Jürgen Schmidt
In this paper we argue that, in addition to the statistical structure of quantum theory, another structure, referred to here as the ``Noether structure," is necessary to describe t…
On the motion of a point charge in a plate capacitor considering influence effects
Heinz-Jürgen Schmidt, Thomas Bröcker
A point charge between the plates of a capacitor generates an influence charge distribution on the plates that modify the electric field acting upon the point charge. This effect i…
Ground states of classical spin polygons: Rigorous results and examples
Wojciech Florek, Heinz-Jürgen Schmidt, Katarzyna Jaśniewicz-Pacer
We present a comprehensive and rigorous analysis of the lowest energy configurations (LECs) of classical spin polygons characterized by arbitrary couplings between neighboring spin…
Coarse-grained entropy balance of the Szilard engine
Heinz-Jürgen Schmidt, Thomas Bröcker
In order to reconcile the entropy reduction of a system through external interventions that are linked to a measurement with the second law of thermodynamics, there are two main pr…
Galilean decoherence and quantum measurement
Heinz-Jürgen Schmidt
In this study, we present a modified quantum theory, denoted as , which introduces mass-dependent decoherence effects. These effects are derived by averaging the influence…
A generalization of the Choi isomorphism with application to open quantum systems
Heinz-Jürgen Schmidt
Completely positive transformations play an important role in the description of state changes in quantum mechanics, including the time evolution of open quantum systems. One usefu…
The magnetization process of classical Heisenberg magnets with non-coplanar cuboc ground states
Johannes Richter, Heinz-Jürgen Schmidt, Jürgen Schnack
We consider a classical Heisenberg model on the kagomé and the square kagomé lattice, where at zero magnetic field non-coplanar cuboctahedral ground states with twelve sublattices…
Species of structure and physical dimensions
Heinz-Jürgen Schmidt
This study addresses the often underestimated importance of physical dimensions and units in the formal reconstruction of physical theories, focusing on structuralist approaches th…
The Rabi problem with elliptic polarization
Heinz-Jürgen Schmidt
We consider the solution of the equation of motion of a classical/quantum spin subject to a monochromatical, elliptically polarized external field. The classical Rabi problem can b…
Ground states of classical magnetic dipole rings
Heinz-Jürgen Schmidt
We investigate the two well-known ground states of rings of classical magnetic dipoles that are given by clockwise or anti-clockwise spin orientations tangent to the circle enc…
Fourier-Taylor series for the figure eight solution of the three body problem
Heinz-Jürgen Schmidt, Thomas Bröcker
We provide an analytical approximation of a periodic solution of the three body problem in celestial mechanics, the so-called figure eight solution, discovered 1993 by C. Moore. Th…
The general spin triangle
Heinz-Jürgen Schmidt
We consider the Heisenberg spin triangle with general coupling coefficients and general spin quantum number . The corresponding classical system is completely integrable. In the…
Eighth-order high-temperature expansion for general Heisenberg Hamiltonians
Heinz-Jürgen Schmidt, Andre Lohmann, Johannes Richter
We explicitly calculate the moments of general Heisenberg Hamiltonians up to eighth order. They have the form of finite sums of products of two factors. The first factor is r…
Generalized Bell inequalities and frustrated spin systems
Heinz-Jürgen Schmidt
We find a close correspondence between generalized Bell inequalities (GBI's) of a special kind and certain frustrated spin systems. For example, the Clauser-Horn-Shimony-Holt inequ…
Structure and relevant dimension of the Heisenberg model and applications to spin rings
K. Baerwinkel, H. -J. Schmidt, J. Schnack
For the diagonalization of the Hamilton matrix in the Heisenberg model relevant dimensions are determined depending on the applicable symmetries. Results are presented, both, by ge…