Home

Charge sensing amplification via weak values measurement


  Oded Zilberberg [1]  ,  Alessandro Romito [2,3]  ,  Yuval Gefen [1]  
 [1] Department of Condensed Matter Physics, The Weizmann Institute of Science, Rehovot 76100, Israel
[2] Institut fuer Theoretische Festkoerperphysik, Universitaet Karlsruhe, D–76128 Karlsruhe, Germany
[3] Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universitaet Berlin, 14195 Berlin, Germany

We propose a protocol employing weak values (WVs) to obtain ultra sensitive amplification of weak signals in the context of a solid state setup [1].

WVs were introduced more than twenty years ago [2] as a peculiarity of quantum mechanics, where the weak measurement of a component of the spin of a spin-1/2 particle can turn out to be 100, far outside the eigenvalue range of the measurement operator.

Going beyond the peculiarities of WV protocols, recent series of works explored the potential of WVs in quantum optics [3–6] and solid state physics [7–9], ranging from their experimental  observation to the application to hyper-sensitive measurements.

Specifically, it has been realized in the quantum optics context that a WV measurement can lead to an amplified signals in the detector that enables sensing of small, otherwise unaccessible quantities, e.g. sensing the deflection angle of a mirror of the order of ∼ 500 femtoradians [6].

We consider an Aharonov-Bohm interferometer where both the orbital and the spin degrees of freedom are weakly affected by the presence of an external charge to be detected. The interplay between the spin and the orbital WVs leads to a significant amplification even in the presence of finite temperatures, voltage, and external noise.

[1] OZ, A. Romito, and Y. Gefen, submitted to PRL (arxiv:1009.4738).

[2] Y. Aharonov, D. Z. Albert, and L. Vaidman, Phys. Rev. Lett. 60, 1351 (1988).

[3] N. W. M. Ritchie, J. G. Story, and R. G. Hulet, Phys. Rev. Lett. 66, 1107 (1991).

[4] G. J. Pryde, J. L. O’Brien, A. G. White, T. C. Ralph, and H. M. Wiseman, Phys. Rev. Lett. 94, 220405 (2005).

[5] O. Hosten and P. Kwiat, Science 319, 787 (2008).

[6] P. B. Dixon, D. J. Starling, A. N. Jordan, and J. C. Howell, Phys. Rev. Lett. 102, 173601 (2009).

[7] N. S. Williams and A. N. Jordan, Phys. Rev. Lett. 100, 026804 (2008).

[8] A. Romito, Y. Gefen, and Y. M. Blanter, Phys. Rev. Lett. 100, 056801 (2008).

[9] V. Shpitalnik, Y. Gefen, and A. Romito, Phys. Rev. Lett. 101, 226802 (2008).