352 citations · 781 across the 16 of their papers we have counts for
16 papers
Noncoplanar orders and quantum disordered states in maple-leaf (anti)ferromagnets
Martin Gembé, Lasse Gresista, Heinz-Jürgen Schmidt +3
A promising route towards the realization of chiral spin liquids is the quantum melting of classically noncoplanar spin states via quantum fluctuations. In the classical realm, suc…
Exotic magnetization curves in classical square-kagomé spin lattices
Heinz-Jürgen Schmidt, Johannes Richter
Classical spin systems with non-coplanar ground states typically exhibit nonlinear magnetization curves characterized by kinks and jumps. Our article briefly summarizes the most im…
The magnetic field does not perform work -- or does it?
Heinz-Jürgen Schmidt, Thomas Bröcker
We investigate the question discussed in the literature as to whether the magnetic field can perform work using two models that describe interacting magnetic dipoles. In the first…
Non-Coplanar Magnetic Orders in Classical Square-Kagome Antiferromagnets
Martin Gembé, Heinz-Jürgen Schmidt, Ciarán Hickey +3
Motivated by the recent synthesis of a number of Mott insulating square-kagome materials, we explore the rich phenomenology of frustrated magnetism induced by this lattice geometry…
Stochastic thermodynamics of a finite quantum system coupled to a heat bath
Heinz-Jürgen Schmidt, Jürgen Schnack, Jochen Gemmer
We consider a situation where an -level system (NLS) is coupled to a heat bath without being necessarily thermalized. For this situation we derive general Jarzinski-type equatio…
High-temperature expansion for frustrated magnets: Application to the J1-J2 model on the BCC lattice
Johannes Richter, Patrick Müller, Andre Lohmann +1
We present the high-temperature expansion up to 11th order for the specific heat and the uniform susceptibility and up to 9th order for the structure factor o…
Magnetic susceptibility of frustrated spin-s J1-J2 quantum Heisenberg magnets: High-temperature expansion and exact diagonalization data
J. Richter, A. Lohmann, H. -J. Schmidt +1
Motivated by recent experiments on low-dimensional frustrated quantum magnets with competing nearest-neighbor exchange coupling J1 and next nearest-neighbor exchange coupling J2 we…
Tenth-order high-temperature expansion for the susceptibility and the specific heat of spin-s Heisenberg models with arbitrary exchange patterns: Application to pyrochlore and kagome magnets
Andre Lohmann, Heinz-Jürgen Schmidt, Johannes Richter
We present the high-temperature expansion (HTE) up to 10th order of the specific heat C and the uniform susceptibility χfor Heisenberg models with arbitrary exchange patterns and a…
Independent magnon states on magnetic polytopes
J. Schnack, H. -J. Schmidt, J. Richter +1
For many spin systems with constant isotropic antiferromagnetic next-neighbour Heisenberg coupling the minimal energies E_{min}(S) form a rotational band, i.e. depend approximately…
Macroscopic magnetization jumps due to independent magnons in frustrated quantum spin lattices
J. Schulenburg, A. Honecker, J. Schnack +2
For a class of frustrated spin lattices including the kagome lattice we construct exact eigenstates consisting of several independent, localized one-magnon states and argue that th…
Heisenberg exchange parameters of molecular magnets from the high-temperature susceptibility expansion
H. -J. Schmidt, J. Schnack, Marshall Luban
We provide exact analytical expressions for the magnetic susceptibility function in the high temperature expansion for finite Heisenberg spin systems with an arbitrary coupling mat…
Partition functions and symmetric polynomials
H. -J. Schmidt, J. Schnack
We find a close correspondence between certain partition functions of ideal quantum gases and certain symmetric polynomials. Due to this correspondence it can be shown that a numbe…
Bounding and approximating parabolas for the spectrum of Heisenberg spin systems
H. -J. Schmidt, J. Schnack, Marshall Luban
We prove that for a wide class of quantum spin systems with isotropic Heisenberg coupling the energy eigenvalues which belong to a total spin quantum number S have upper and lower…
Transition from quantum to classical Heisenberg trimers: Thermodynamics and time correlation functions
D. Mentrup, H. -J. Schmidt, J. Schnack +1
We focus on the transition from quantum to classical behavior in thermodynamic functions and time correlation functions of a system consisting of three identical quantum spins s th…
Ground state properties of antiferromagnetic Heisenberg spin rings
K. Baerwinkel, H. -J. Schmidt, J. Schnack
Exact ground state properties of antiferromagnetic Heisenberg spin rings with isotropic next neighbour interaction are presented for various numbers of spin sites and spin quantum…
Thermodynamic fermion-boson symmetry in harmonic oscillator potentials
H. -J. Schmidt, J. Schnack
A remarkable thermodynamic fermion-boson symmetry is found for the canonical ensemble of ideal quantum gases in harmonic oscillator potentials of odd dimensions. The bosonic partit…