The Bloch sphere provides a geometric representation of a qubit. In classical information theory, a bit can exist in one of two possible states ‘0’ or ‘1’, represented by the poles of the sphere. The state of a qubit can be any one of an infinite number of points along the surface of the Bloch sphere. The poles of the sphere represent the computational states Embedded Image and Embedded Image of the qubit and all other points (such as that indicated by the blue arrow) describe a coherent superposition of these states Embedded Image, subject to the normalization condition Embedded Image. The counterintuitive property of quantum coherence leads to many uniquely quantum phenomena, such as the superior power of quantum information processing protocols or the formation of Bose–Einstein condensation in gasses of ultra-cold atoms.
29 NOVEMBER 2015

The quantum physics of Libertango

Physicist-ballerina Merritt Moore danced her PhD to Astor Piazzolla’s Libertango – a brilliant cascade of metaphors that kicks off with the choice of tango, Moore’s razor-sharp pointework tracing the contours of the Bloch sphere of a two-level quantum mechanical system.…

Wendy Rein of RAWdance (Photo: RJ Muna)
28 NOVEMBER 2015

Vital signs: Is contemporary dance alive and kicking in San Francisco?

Leigh Donlan reports from ground zero of contemporary dance in San Francisco:

The arts are the best insurance policy a city can take on itself.

– Woody Dumas, former Mayor of Baton Rouge

San Francisco was once a magnet for artists, an ideal place for them to settle and thrive. …