Wednesday, September 15, 2004

"QUANTUM: Yale team builds chips for quantum computing"
Demonstrating a new paradigm for quantum computing, Yale University researchers have built what they call QED integrated circuits to manipulate quantum bits. While the almost mystical allure of quantum computing has been verified time and again using qubits in a physics lab, building real circuitry on silicon chips has had only sporadic success, until now. The QED-for quantum electrodynamics-circuits operate on quantum bits by using a superconducting "Cooper box" to store oscillating microwave photons that can be read and written without disturbing their quantum states. Quantum computers promise to outpace digital computers by using qubits, which can represent a superposition of simultaneous values, thereby achieving parallel processing without parallel hardware. "I think that EEs understand how qubits involve a superposition of quantum states, but they may not know that you can build integrated circuits that way," said Steven Girvin, a professor of physics at Yale. By superpositioning quantum states that simultaneously perform parallel operations, quantum computers can break encryption codes and work other technological miracles that a digital computer would find impossible. Many quantum state mechanisms, some of them potential building blocks for future quantum computers, have been demonstrated in physics labs. But Yale's demonstration of how to build chips using what it calls "qutons"-a qubit on a photon-enable quantum computers using QED circuits to be put onto chips today