Charles D. Hill

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Quantum communication typically involves a linear chain of repeater stations, each capable of reliable local quantum computation and connected to their nearest neighbors by unreliable communication links. The communication rate of existing protocols is low as two-way classical communication is used. By using a surface code across the repeater chain and(More)
The exceptionally long quantum coherence times of phosphorus donor nuclear spin qubits in silicon, coupled with the proven scalability of silicon-based nano-electronics, make them attractive candidates for large-scale quantum computing. However, the high threshold of topological quantum error correction can only be captured in a two-dimensional array of(More)
Recent work on fault-tolerant quantum computation making use of topological error correction shows great potential, with the 2d surface code possessing a threshold error rate approaching 1% [1, 2]. However, the 2d surface code requires the use of a complex state distillation procedure to achieve universal quantum computation. The colour code of [3] is a(More)
  • Judith Brinkschulte, C. Denson Hill, Mauro Nacinovich, JUDITH BRINKSCHULTE, MAURO NACINOVICH
  • 2001
In this paper, we consider the boundary M of a weakly pseudoconvex domain in a Stein manifold. We point out a striking difference between the local cohomology and the global cohomology of M, and illustrate this with an example. We also discuss the first and second Cousin problems, and the strong Poincaré problem for CR meromorphic functions on the weakly(More)
  • Judith Brinkschulte, C. Denson Hill, Mauro Nacinovich, MAURO NACINOVICH
  • 2001
It is necessary to make two tiny corrections in [BHN]. This is because the last two authors, having become aware of some inconsistencies in [HN1], have repaired the situation in [HN2], but the results they obtained are slightly different than what was originally claimed. Namely, for local results, it is important to make a distinction between the vanishing(More)
A number of elegant approaches have been developed for the identification of quantum circuits which can be efficiently simulated on a classical computer. Recently, these methods have been employed to demonstrate the classical simulability of the quantum Fourier transform (QFT). Here we show that one can demonstrate a number of simulability results for QFT(More)
In this paper we demonstrate how data encoded in a five-qubit quantum error correction code can be converted, fault-tolerantly, into a seven-qubit Steane code. This is achieved by progressing through a series of codes, each of which fault-tolerantly corrects at least one error. Throughout the conversion the encoded qubit remains protected. We found, through(More)
While it is known that shared quantum entanglement can offer improved solutions to a number of purely cooperative tasks for groups of remote agents, controversy remains regarding the legitimacy of quantum games in a competitive setting—in particular, whether they offer any advantage beyond what is achievable using classical resources. We construct a(More)