Generation of photon n-states: the quantum eraser

Draven W. Houser

Dylan Danese, Sabine Wollmann, Saroch Leedumrongwatthanakun +4 more

Demonstration of two-photon entanglement in the transverse Laguerre-Gaussian basis by performing a “twisted” quantum eraser. The state is generated using linear optics and measured using full state tomography with a fidelity up to 95.31%.

Shengwang Du

Akira Furusawa

Jan-Wilke Henke, Hao Jeng, Claus Ropers

We propose a tangible experimental scheme for demonstrating quantum entanglement between swift electrons and light, relying on coherent cathodoluminescence for photon generation in a transmission electron microscope, and a quantum eraser setup for formation and verification of entanglement. The entanglement of free electrons with light is key to developing free-electron quantum optics and its potential applications such as quantum sensing, novel photonic and electron state generation, and entanglement between free electrons.

Dylan Danese, Sabine Wollmann, Saroch Leedumrongwatthanakun +4 more

We demonstrate the generation of unbalanced two-photon entanglement in the Laguerre–Gaussian (LG) transverse-spatial degree-of-freedom, where one photon carries a fundamental (Gauss) mode and the other a higher-order LG mode with a non-zero azimuthal (ℓ) or radial (p) component. Taking a cue from the N00N state nomenclature, we call these types of states ℓ00ℓ-entangled. They are generated by shifting one photon in the LG mode space and combining it with a second (initially uncorrelated) photon at a beamsplitter, followed by coincidence detection. In order to verify two-photon coherence, we demonstrate a two-photon “twisted” quantum eraser, where Hong–Ou–Mandel interference is recovered between two distinguishable photons by projecting them into a rotated LG superposition basis. Using an entanglement witness, we find that our generated states have fidelities of 95.31% and 89.80% to their respective ideal maximally entangled states. In addition to being of fundamental interest, this type of entanglement will likely have a significant impact on tickling the average quantum physicist's funny bone.