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. At Different Places at Once - According to the law of quantum physics, particles can be in different physical states at the same time. If, for example, a beam of neutrons is divided into two beams using a silicon crystal, it can be shown that the individual neutrons do not have to decide which of the two possible paths they choose.