5 papers
The Wigner Kernel of a Particle obtained from the Wigner Kernel of a Spin by Group Theoretical Contraction
Jean-Pierre Amiet, Stefan Weigert
The Moyal formalism for a particle can be derived from the Moyal formalism for a spin. This is done by contracting the group of rotations to the oscillator group. A new derivation…
A Discrete Phase-Space Calculus for Quantum Spins based on a Reconstruction Method using Coherent States
Stefan Weigert
To reconstruct a mixed or pure quantum state of a spin s is possible through coherent states: its density matrix is fixed by the probabilities to measure the value s along 4s(s+1)…
Coherent States and the Reconstruction of Pure Spin States
Jean-Pierre Amiet, Stefan Weigert
Coherent states provide an appealing method to reconstruct efficiently a pure state of a quantum mechanical spin s. A Stern-Gerlach apparatus is used to measure (4s+1) expectations…
Gauge transformations for a driven quantum particle in an infinite square well
Stefan Weigert
Quantum mechanics of a particle in an infinite square well under the influence of a time-dependent electric field is reconsidered. In some gauge, the Hamiltonian depends linearly o…
Reconstruction of spin states and its conceptual implications
Stefan Weigert
State reconstruction for quantum spins is reviewed. Emphasis is on non-tomographic approaches which are based on measurements performed with a Stern-Gerlach apparatus. Two conseque…