Quantum Computer Simulated

An artist's rendition of an integrated circuit in a futuristic quantum computer proposed by researchers at Yale University.  The circuit -- the zipper-like structure -- is composed of a "qubit" which can store quantum bits of information in the form of photons. 

The researchers can now reliably generate a single photon "on chip and on demand," an essential feature of a real quantum computer.  In the photon generation, an energetically excited qubit can reduce its energy by emitting a photon onto the central wire that connects the qubit to a qubit at another location.   When the qubit is in its lowest energy state, no photons can be emitted.  That is how the researchers make a photon "on demand." 

The colorful starburst is actually a theory calculation showing how the spectrum of the qubit splits from a single peak into several peaks as the researchers change the number of photons in the cavity that encases the qubit. 

Credit: David Schuster, Yale University