Experimental Realization of Multipartite Entanglement of 60 Modes of a Quantum Optical Frequency Comb

Phys Rev Lett. 2014 Mar 28;112(12):120505. doi: 10.1103/PhysRevLett.112.120505. Epub 2014 Mar 26.


We report the experimental realization and characterization of one 60-mode copy and of two 30-mode copies of a dual-rail quantum-wire cluster state in the quantum optical frequency comb of a bimodally pumped optical parametric oscillator. This is the largest entangled system ever created whose subsystems are all available simultaneously. The entanglement proceeds from the coherent concatenation of a multitude of Einstein, Podolsky, and Rosen pairs by a single beam splitter, a procedure which is also a building block for the realization of hypercubic-lattice cluster states for universal quantum computing.