Counterfactual quantum erasure: spooky action without entanglement

Abstract

We combine the eyebrow-raising quantum phenomena of erasure and counterfactuality for the first time, proposing a simple yet unusual quantum eraser: A distant Bob can decide to erase which-path information from Alice’s photon, dramatically restoring interference—without previously shared entanglement, and without Alice’s photon ever leaving her laboratory.

Keywords

• quantum interference
• entanglement
• quantum erasure
• interaction-free measurement
• zeno effect
• counterfactual communication