New preprint

Read our new preprint describing an entanglement experiment using intense laser pulses.

The results of measurements in quantum mechanics depend on the information available on a quantum system. This quantum-weirdness is impressively demonstrated by the so-called quantum eraser experiment. If which-way information on the path that an otherwise coherent particle takes, it will no longer interfere with itself. However, the interference pattern can be restored - even by postselection, i.e. after the measurement was completed - by erasing the which-way information!

In our recent work, we demonstrate such an experiment in the context of ultrafast photoionization of a $D_2$ molecule. The interaction of the molecule with an intense laser pulse creates an entangled state between a photoelectron and a residual ion. Owing to the entanglement, “which-way” information may become available, which causes the electron’s holographic interference fringes (top right panel) to disappear (bottom right panel). We show that selecting a specific ionic state erases the which-way information, which restores the interference pattern. The results are fully supported by theoretical models.

The preprint is available on the arXiv.