Light's dual nature survives space

Abstract

The mysterious wave-particle duality of the quantum world has been tested using satellites--setting a new distance record of more than 3000 kilometers for a detection of this bizarre behavior. People know that photons are quanta of energy, or particles, but in some experiments these particles can act like waves. According to standard quantum physics, they can observe either the wave nature or the particle nature, but never both at the same time. Whenever they try, the act of measuring the photon forces it to behave as one or the other. In recent decades, experiments have validated Wheeler's ideas. But the longest distance traveled by a photon in these tests was about 140 kilometers. Now, Paolo Villoresi at the University of Padua in Italy and his team have used satellites to test quantum mechanics over thousands of kilometers, paving the way for applications in space