Quantum mechanical approaches to information processing
Steven Prawer · 2006
Unless new paradigms can be developed for information processing the end is in sight for Moore's Law which has guided the development of the computer industry for nearly half a century. One such paradigm shift is to design and engineer a new generation of algorithms and devices which exploit fundamental quantum mechanical properties such as quantum superposition and entanglement for both information processing and transmission. Entanglement offers the possibility of enormous speed up due to massively parallel operation. However, this requires new ways of thinking regarding the very nature of information processing in which measurement and read-out are intrinsic to successful quantum algorithms. For transmission of information, quantum superposition offers the possibility of communications whose absolute security is guaranteed by the laws of quantum mechanics. But how close are we to being able to translate this potential into practical machines? The technical challenges are formidable because these devices need to control and manipulate individual atoms, electrons or photons. Nevertheless impressive progress has been made over the past five years. The very simplest devices which involve only one or two active quantum bits (qubits) are already finding application in ultra-secure communications systems using quantum key distribution. This requires a single photon source (i.e. a source that produces one and only one photon per pulse) and we will review our progress in fabricating such sources based on advanced diamond technology. Scaling up to many qubit architectures is even more challenging, but highly sophisticated devices which operate at the single electron level have recently been demonstrated. These devices represent the basic building blocks for a quantum information processor which, when integrated, may from the basis of practical quantum computing machines. In this talk, I will attempt to show how recent progress provides a glimpse into one possible version of tomorrow's computing world.