Counterfactual Ghost Imaging

Abstract

We give a protocol for ghost imaging in a way that is always counterfactual -while imaging an object, no light interacts with that object. This extends the idea of counterfactuality beyond communication, showing how this interesting phenomenon can be leveraged for metrology. Given, in the infinite limit, no photons ever go to the imaged object, it presents a method of imaging even the most light-sensitive of objects without damaging them. Even when not in the infinite limit, it still provides a many-fold improvement in visibility and signal-to-noise ratio over previous protocols, with up to multiple orders of magnitude reduction in absorbed intensity.

Could wavefunctions simultaneously represent knowledge and reality?

“…This is unlike quantum 'probability amplitudes', which are really quasiprobabilities -they can be negative or even imaginary, and so can interfere destructively with one another. This negative probability interference is a key part of quantum mechanics, explaining peculiar phenomena such as the sequential Stern-Gerlach experiment [33], the Elitzur-Vaidman Bomb Detector [34], and counterfactual communication [35,36] and imaging [37]. It is unclear how the real non-negative probabilities of this real underlying state-of-the-world could replicate these effects -casting doubt on this framework.…”