Heidelberg 2015 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 50: Quantum Information: Concepts and Methods VII
Q 50.3: Vortrag
Donnerstag, 26. März 2015, 11:30–11:45, K/HS1
Scalable Reconstruction of Unitary Processes and Hamiltonians — •Milan Holzäpfel1, Tillmann Baumgratz1,2, Marcus Cramer1, and Martin B. Plenio1 — 1Institut für Theoretische Physik, Albert-Einstein-Allee 11, Universität Ulm, 89069 Ulm, Germany — 2Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU Oxford, United Kingdom
Based on recently introduced efficient quantum state tomography schemes, we propose a scalable method for the tomography of unitary processes and the reconstruction of Hamiltonians [1]. As opposed to the exponential scaling with the number of subsystems of standard quantum process tomography, the method relies only on measurements of linearly many local observables and either (a) the ability to prepare eigenstates of locally informationally complete operators or (b) access to an ancilla of the same size as the to-be-characterized system and the ability to prepare a maximally entangled state on the combined system. As such, the method requires at most linearly many states to be prepared and linearly many observables to be measured. The quality of the reconstruction can be quantified with the same experimental resources that are required to obtain the reconstruction in the first place. Our numerical simulations of several quantum circuits and local Hamiltonians suggest a polynomial scaling of the total number of measurements and post-processing resources.
[1] M. Holzäpfel, T. Baumgratz, M. Cramer, and M.B. Plenio, arXiv:1411.6379