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DY: Fachverband Dynamik und Statistische Physik
DY 11: Quantum Dynamics, Decoherence, and Quantum Information II
DY 11.7: Talk
Tuesday, March 23, 2010, 15:45–16:00, H38
Weak to strong values crossover in many body systems — •Alessandro Romito1, Yuval Gefen2, and Yaroslav Blanter3 — 1Karlsruher Institut für Technologie (KIT), Institut für Theoretische Festkörperphysik, 76128 Karlsruhe, Germany — 2Department of Condensed Matter Physics, Weizmann Institute of Science, 76100 Rehovot, Israel — 3Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
Weak quantum measurement, as opposed to (strong) projective ones described by the projection postulate, provide partial information about the state of the system, while weakly disturbing it. A remarkably effect in this context is the appearance of ``weak values'' [1] as a result of a two-step measurement procedure -- weak measurement followed by a strong one, where the outcome of the first measurement is kept provided a second post-selected outcome occurs. They have proven to be a remarkable concept in addressing fundamental aspects of quantum mechanics and applications to metrology. We have recently addressed the measurement of weak values in solid state physics.
Here I review some of the ideas associated with weak values, including the first proposal to observe weak values in a solid state system. I will then discuss the generalization of weak values to many-body systems specifically considering an electronic Mach-Zehnder interferometer. Within the same setup I will discuss the crossover between weak and strong values.
[1] Y. Aharonov, D. Z. Albert, L. Vaidman, Phys. Rev. Lett. 60, 1351-1354 (1988).