Fast quantum logic by selective displacement of hot trapped ions
Physical Review A - Atomic, Molecular, and Optical Physics 67:6 (2003) 623181-6231819
Abstract:
A report on the fast quantum logic by selective displacement of hot trapped ions was presented in the article. The effect of imperfections in a pair of π pulses which are used to implement a 'spin echo' to cancel correlated errors was also analyzed. It was found that whereas the pushing gate is not as resistant to imperfection as was supposed, it remains a significant candidate for ion trap quantum computing since it does not require ground state cooling.Quantum computation with ions in microscopic traps
SUPERLATTICE MICROST 32:4-6 (2002) 195-213
Abstract:
We discuss a possible experimental realization of fast quantum gates with high fidelity with ions confined in microscopic traps. The original proposal of this physical system for quantum computation comes from Cirac and Zoller (Nature 404, 579 (2000)). In this paper we analyse a sensitivity of the ion-trap quantum gate on various experimental parameters which was omitted in the original proposal. We address imprecision of laser pulses, impact of photon scattering, nonzero temperature effects and influence of laser intensity fluctuations on the total fidelity of the two-qubit phase gate. (C) 2003 Elsevier Ltd. All rights reserved.Quantum computer architecture for fast entropy extraction
Quantum Information and Computation 2:4 (2002) 297-306
Abstract:
If a quantum computer is stabilized by fault-tolerant quantum error correction (QEC), then most of its resources (qubits and operations) are dedicated to the extraction of error information. Analysis of this process leads to a set of central requirements for candidate computing devices, in addition to the basic ones of stable qubits and controllable gates and measurements. The logical structure of the extraction process has a natural geometry and hierarchy of communication needs; a computer whose physical architecture is designed to reflect this will be able to tolerate the most noise. The relevant networks are dominated by quantum information transport, therefore to assess a computing device it is necessary to characterize its ability to transport quantum information, in addition to assessing the performance of conditional logic on nearest neighbours and the passive stability of the memory. The transport distances involved in QEC networks are estimated, and it is found that a device relying on swap operations for information transport must have those operations an order of magnitude more precise than the controlled gates of a device which can transport information at low cost.Quantum computing and error correction
NATO SC S SS III C S 182 (2001) 284-298