Quantum Electron Microscope

An electron microscope that doesn’t destroy the sample

Quantum mechanics allows to measure the existence of an object without touching it, known as interaction-free measurement [1], [2]. We want to develop an electron microscope based on this measurement principle in order to overcome the detrimental radiation damage. Read more in this press release, in the program overview below or find us on  facebook.

Program overview

Interaction-free measurement as proposed in Ref. [3]. Say the electron starts circulating in the upper ring and the upper and lower rings are coherently coupled. After the characteristic coupling timescale, if there is no absorber in the lower ring (left), the electron will completely transfer to the lower ring. If there is an absorber (right), there is no coherent build-up of the electron wave function in the lower ring and it stays in the upper ring, which is a manifestation of the quantum Zeno effect. As the electron can now be measured in the upper ring, the existence of the absorber is inferred without having interacted with the electron. Fig. from Ref. [3].

A new microscopy tool based on quantum physics and electron microscopy will be investigated. The proposed Quantum Electron Microscope (QEM), see Ref. [3] for a possible implementation, may enable imaging of biological samples with radiation doses so small that they are non-lethal. The instrument will rely on the interaction-free (IFM) nondestructive measurement principle [1], which has been proven with photons [2], but has yet to be demonstrated with electrons. The development program seeks to advance the state-of-knowledge in order to assess the realism of such an instrument. In recent years, new approaches have emerged which allow for unprecedented levels of control over the quantum motion of electrons in free space. We seek to exploit these methods to make proof-of-principle demonstrations of the IFM measurement principle. We anticipate that these foundation experiments will have technology impact beyond microscopy. For example, extensions of the IFM principle allow for controlled entanglement of electron wavefunctions, enabling, for example demonstration of free electronbased CNOT.

We are part of an international collaboration, which is funded by the Betty and Gordon Moore foundation.

If you have any questions or comments or want to join our team, feel free to contact one of us.

References

[1] A. C. Elitzur and L. Vaidman, Found. Phys. 23, 987 (1993)
[2] P. Kwiat, H. Weinfurter, T. Herzog, A. Zeilinger, and M. A. Kasevich, Phys. Rev. Lett. 74, 4763 (1995)
[3] W. P. Putnam and M. F. Yanik, Phys. Rev. A 80, 040902(R) (2009)

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