2001/06/30 by Dominik Janzing, Paweł Wocjan, Pawel Wocjan +1 · 1 citation
Chemistry · Physics and Astronomy · #Advanced NMR Techniques and Applications #Atomic and Subatomic Physics Research #Quantum chaos and dynamical systems #quant-ph
paper · pdf · doi:10.1103/physreva.66.042311
published as Phys. Rev. A 66, 042311, 2002 · Completely rewritten, new lower bounds on the number of time steps, applications and references added
arxiv created 2002/02/15 · openalex publication_date 2002/10/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Well-known nuclear magnetic resonance experiments show that the time evolution according to (truncated) dipole-dipole interactions between n spins can be inverted by simple pulse sequences. Independent of n, the reversed evolution is only two times slower than the original one. Here we consider more general spin-spin couplings with long range. We prove that some are considerably more complex to invert since the number of required time steps and the slow-down of the reversed evolutions are necessarily of the order n. Furthermore, the spins have to be addressed separately. We show for which values of the coupling parameters the phase transition between simple and complex time-reversal schemes occurs.