EPJ Quantum Technol. (2019) 6: 4
https://doi.org/10.1140/epjqt/s40507-019-0074-y

Research

Encrypted quantum correlations: delayed choice of quantum statistics and other applications

¹ Département de Physique, École Normale Supérieure, PSL Université, CNRS, Paris, France
² Laboratoire Kastler Brossel, ENS-PSL, CNRS, Sorbonne Université, Collège de France, Paris, France
³ QSTAR, CNR-INO and LENS, Firenze, Italy

^* e-mail: manuel.gessner@ens.fr

Received: 9 July 2019
Accepted: 25 September 2019
Published online: 1 October 2019

Abstract

In a three-particle extension of Wheeler’s delayed choice gedanken experiment, the quantum statistics of two particles is undetermined until a third particle is measured. As a function of the measurement result, the particles behave either as bosons or as fermions. The particles are distinguishable if no measurement is performed at all or when the measurement is performed in a rotated basis. The scheme is based on Greenberger–Horne–Zeilinger quantum correlations. It can be interpreted more generally as the encryption of maximally entangled states in a larger quantum superposition. The local quantum information is scrambled but can be decoded by the measurement result of a control particle. This can be extended to multiple particles and allows to develop quantum information protocols whose successful implementation depends on the collaboration of all parties.