Eur. Phys. J. D 18, 251-258 (2002)
https://doi.org/10.1140/epjd/e20020030

Comprehensive experimental test of quantum erasure

¹ Department of Microelectronics and Information Technology, Royal Institute of Technology (KTH), Electrum 229, 16440 Kista, Sweden
² Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, 194021 St. Petersburg, Russia

Corresponding author: ^a alexei@ele.kth.se

Received: 15 July 2001
Revised: 30 November 2001
Published online: 15 February 2002

Abstract

In an interferometer, path information and interference visibility are incompatible quantities. Complete determination of the path will exclude any possibility of interference, rendering zero visibility. However, it is, under certain conditions, possible to trade the path information for improved (conditioned) visibility. This procedure is called quantum erasure. We have performed such experiments with polarization-entangled photon pairs. Using a partial polarizer, we could vary the degree of entanglement between the object and the probe. We could also vary the interferometer splitting ratio and thereby vary the a priori path predictability. This allowed us to test quantum erasure under a number of different experimental conditions. All experiments were in good agreement with theory.