July 30, 2014

The Quantum Cheshire Cat

Can neutrons be located at a different place than their own spin? A quantum experiment, carried out by a team of researchers from the Vienna University of Technology, demonstrates a new kind of quantum paradox.

The Cheshire Cat featured in Lewis Caroll’s novel “Alice in Wonderland” is a remarkable creature: it disappears, leaving its grin behind. Can an object be separated from its properties? It is possible in the quantum world. In an experiment, neutrons travel along a different path than one of their properties – their magnetic moment. This “Quantum Cheshire Cat” could be used to make high precision measurements less sensitive to external perturbations.