Quantum physics: Losing a grip on realit
It seems common sense that an object will retain its fundamental properties regardless of whether or not we are looking at it. But in the microscopic quantum world, everyday rules do not apply. Even our concept of reality may be challenged.
Classical physics clings tightly to the notions of realism (where external reality exists independent of observation) and locality (where sufficiently distant objects cannot influence each other). Quantum experiments in which the properties of distant but entangled particles are linked seem hard to reconcile with such notions, making local realistic theories untenable.
Markus Aspelmeyer, Anton Zeilinger and colleagues developed an inequality that relaxes the assumption of locality, allowing a test of non-local realism. They studied correlations between pairs of entangled photons, and found that the correlations violate non-local realistic theories. The result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned.
CONTACT
Markus Aspelmeyer (University of Vienna, Austria)
Please contact the author through:
Ursula Gerber (University of Vienna, Austria)
Tel: +43 1 4277 51205; E-mail: ursula.gerber@univie.ac.at
Alain Aspect (Institut d'Optique, Palaiseau, France) N&V author
Tel: +33 1 64 53 31 03; E-mail: alain.aspect@institutoptique.fr