Different Schemes of Quantum Computation with Cold Trapped Ions

D.F.V. James

Cassius D'Helon, Gerard J Milburn

J. I. Cirac

Mang Feng, Xiaoguang Wang

We propose a scheme to perform basic gates of quantum computing and prepare entangled states in a system with cold trapped ions located in a single-mode optical cavity. General quantum computing can be done with both the motional state of the trapped ion and cavity state being qubits. We can also generate different kinds of entangled states in such a system without state reduction, and can transfer quantum states from an ion in one trap to an ion in another trap. The experimental requirements for achieving our scheme are discussed.

Stefano Olivares

J. F. Poyatos, J. I. Cirac, P. Zoller

The purpose of this article is to review two complementary schemes for quantum computation with trapped ions. We initially discuss the first proposal of quantum computations with cold trapped ions (J. I. Cirac and P. Zoller; Phys. Rev. Lett. 74, 4091, 1995) which requires, prior to any computation, laser cooling to the motional ground state. This proposal is closely related to the physics of generating and manipulating N-particles entangled states in both ion traps and high-Q cavities (cavity quantum electrodynamics). The second scheme is that of quantum computations with hot trapped ions (J.F. Poyatos, J.I. Cirac and P. Zoller; Phys. Rev. Lett. 81, 1322, 1998) which works at finite temperature and resembles physical ideas found in atom interferometry.