Dresden 2009 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 44: Transport: Quantum Coherence and Quantum Information
TT 44.6: Talk
Thursday, March 26, 2009, 15:30–15:45, HSZ 304
Weak Values in solid state physics — Vadim Shpitalnik1, Yuval Gefen1, and •Alessandro Romito1,2 — 1Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel — 2Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany
The measurement of any observable in quantum mechanics is a probabilistic process described by the projection postulate. As opposed to projective (strong) measurement, weakly measuring an observable (i.e., measuring it while weakly disturbing the system), provides only partial information on the state of the system. It has been proposed that a weak measurement on pre and post-selected ensembles -- i.e. a weak measurement followed by a strong one, where the outcome of the first measurement is kept provided a second post-selected outcome occurs -- leads to a weak value [1]. Such a weak value may lie well beyond the range of strong values and may happen to be complex.
Here we study a weak value protocol in the context of a solid state setup, specifically, an electronic Mach-Zehnder interferometry [2] presenting the first specific proposal for full tomography of weak values. We generalization of weak values to non-pure states, and we further analyze the manifestation of many-body physics in the weak value, including finite temperature and shot-noise-like contributions.
[1] Y. Aharonov, D. Z. Albert, L. Vaidman, Phys. Rev. Lett. 60, 1351-1354 (1988).
[2] V. Shpitalnik, Y. Gefen, and A. Romito, Phys. Rev. Lett. 101, 226802 (2008).