An Introduction to Quantum Computing
12 Sep 2008 | Online Presentations | Contributor(s): Edward Gerjuoy
Quantum mechanics, as formulated more than 80 years ago by Schrodinger, Heisenberg, Dirac and other greats, is a wholly sufficient foundation for its modern interrelated subfields of quantum computation (qc) and quantum information (qi), which generally are lumped together into a single subfield (qc/qi). In short qc/qi, though it has been exciting the attention of a very rapidly increasing number of physicists, involves no genuinely new physics. On the other hand some of the important features and implications of quantum mechanics had been only barely appreciated before the advent of qc/qi researches, about 25 years ago. The first portion of this talk will define the fundamental qc component, namely the qubit, and will describe some possible physical realizations of qubits. The talk then will focus on one alluded-to feature (entanglement) and one implication (the so-called no cloning theorem), which for unfathomable reasons still receive little or no attention in modern quantum mechanics texts. The talk will close with an explanation (as detailed as time permits) of how a qc computation actually is performed. This explanation will involve pertinent brief references, but no more than brief references, to the so-called Shor factoring algorithm, which provides the best known illustration of the potential power of qc; an adequate explication of Shor’s algorithm would require a full colloquium in itself. My entire talk should be quite comprehensible to any graduate student who has taken an introductory course in quantum mechanics, even if only at the undergraduate level.