Artificial Edge in An Optical Lattice (image) Goethe University Frankfurt Caption Artificial edge in an optical lattice (blue), filled with an ultracold quantum gas that consists of 'spin-up' particles (red) and 'spin-down' particles (green). Along the edge - and only there - 'spin-up' particles can only flow to the left, and 'spin-down' particles can only flow to the right. Credit Bernhard Irsigler Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.