Quantum interference enables constant-time quantum information processing

Quantum Information Processing in Continuous Time

Quantum mechanical computers can solve certain problems asymptotically faster than any classical computing device. Several fast quantum algorithms are known, but the nature of quantum speedup is not well understood, and inventing new quantum algorithms seems to be difficult. In this thesis, we explore two approaches to designing quantum algorithms based on continuous-time Hamiltonian dynamics. ...

Coherent Control of Quantum Entropy via Quantum Interference in a Four-Level Atomic System

The time evaluation of quantum entropy in a four-level double- type atomic system is theoretically investigated. Quantum entanglement of the atom and its spontaneous emission fields is then discussed via quantum entropy. It is found that the degree of entanglement can be increased by the quantum interference induced by spontaneous emission. The phase dependence of the atom-field entanglement is...

Quantum Information and Electron Interference

Nanotechnologists at the University of Twente research institute MESA+ have discovered a new fundamental property of electrical currents in very small metal circuits. They show how electrons can spread out over the circuit like waves and cause interference effects at places where no electrical current is driven. The geometry of the circuit plays a key role in this so called nonlocal effect. The...

Quantum Games Seminar in Quantum Information Processing

Quantum-information processing with circuit quantum electrodynamics

Alexandre Blais, Jay Gambetta, A. Wallraff, D. I. Schuster, S. M. Girvin, M. H. Devoret, and R. J. Schoelkopf Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA Département de Physique et Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1 Department of Physics, ETH Zurich, CH-8093 Zürich, S...