A two-fold quantum delayed-choice experiment in a superconducting circuit

TL;DR

This paper presents a novel two-fold quantum delayed-choice experiment using superconducting circuits, demonstrating control over wave-particle duality and the ability to recover interference via a quantum eraser, showcasing advanced quantum measurement techniques.

Contribution

It introduces a two-fold quantum delayed-choice setup in superconducting circuits, enabling post-selection of wave or particle nature twice and demonstrating enhanced control over quantum complementarity.

Findings

Successfully demonstrated wave-particle post-selection twice

Recovered interference signals using quantum eraser techniques

Showed quantum WPD provides unprecedented control in delayed-choice experiments

Abstract

We propose and experimentally demonstrate a two-fold quantum delayed-choice experiment where wave or particle nature of a superconducting interfering device can be post-selected twice after the interferometer. The wave-particle complementarity is controlled by a quantum which-path detector (WPD) in a superposition of its on and off states implemented through a superconducting cavity. The WPD projected to its on state records which-path information, which manifests the particle nature and destroys the interference associated with wave nature of the system. In our experiment, we can recover the interference signal through a quantum eraser even if the WPD has selected out the particle nature in the first round of delayed-choice detection, showing that a quantum WPD adds further unprecedented controllability to test of wave-particle complementarity through the peculiar quantum delayed-choice measurements.