Abstract: A fault-tolerant quantum computing scheme implements quantum computing based on three-dimensional cluster states using just a small number of physical components. The technique may be implemented using a single actively controlled qubit [100], e.g., a quantum emitter, and a pair of delay line loops [106, 108], which can be physically realized using existing technologies in quantum photonic and phononic systems. A three-dimensional cluster state is prepared by using the actively con-trolled qubit to generate data qubits that propagate through the two delay line loops, interact with the actively controlled qubit, and then are measured by a detector [110].

Abstract: A fault-tolerant quantum computing scheme implements quantum computing based on three-dimensional cluster states using just a small number of physical components. The technique may be implemented using a single actively controlled qubit [100], e.g., a quantum emitter, and a pair of delay line loops [106, 108], which can be physically realized using existing technologies in quantum photonic and phononic systems. A three-dimensional cluster state is prepared by using the actively con-trolled qubit to generate data qubits that propagate through the two delay line loops, interact with the actively controlled qubit, and then are measured by a detector [110].

Abstract: A system for providing extreme ultraviolet (EUV) radiation comprises a laser source arranged to produce a laser beam having a focus; and a carrier movable relative to the laser source for carrying a surface material, the surface material when carried by the carrier providing a renewable target edge. The focussed beam is arranged to impinge on the target edge to produce an EUV radiation emitting plasma. The system is cooperable with a mirror for harnessing the EUV radiation by reflecting EUV radiation impinging thereon. The mirror comprises a substantially aspheric surface and means for supplying a reflecting liquid to at least partially coat the aspheric surface, the mirror being rotatable to centrifugally confine the liquid to the aspheric surface.

Abstract: A system for providing extreme ultraviolet (EUV) radiation comprises a laser source arranged to produce a laser beam having a focus; and a carrier movable relative to the laser source for carrying a surface material, the surface material when carried by the carrier providing a renewable target edge. The focussed beam is arranged to impinge on the target edge to produce an EUV radiation emitting plasma. The system is cooperable with a mirror for harnessing the EUV radiation by reflecting EUV radiation impinging thereon. The mirror comprises a substantially aspheric surface and means for supplying a reflecting liquid to at least partially coat the aspheric surface, the mirror being rotatable to centrifugally confine the liquid to the aspheric surface.