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Q: Fachverband Quantenoptik und Photonik
Q 39: Quanteninformation: Konzepte V
Q 39.4: Talk
Wednesday, March 4, 2009, 17:15–17:30, VMP 6 HS-D
Coupling strength estimation for spin chains despite restricted access — •Daniel Burgarth1, Koji Maruyama2, and Franco Nori2 — 1Imperial College, London, England — 2RIKEN, Wako-Shi, Japan
Quantum control requires full knowledge of the system many-body Hamiltonian. In many cases this information is not directly available due to restricted access to the system. Here, we show how all coupling strengths in a spin chain can be indirectly estimated by measuring one spin at the end of the chain. The Hamiltonian we study is given by H=∑n cn σn→ · σn+1→ where the cn are arbitrary nearest-neighbor coupling strengths to be estimated. We also discuss the efficiency of the estimation and give a numerical example.