1,352 research outputs found
Quantum Computing and Nuclear Magnetic Resonance
Quantum information processing is the use of inherently quantum mechanical
phenomena to perform information processing tasks that cannot be achieved using
conventional classical information technologies. One famous example is quantum
computing, which would permit calculations to be performed that are beyond the
reach of any conceivable conventional computer. Initially it appeared that
actually building a quantum computer would be extremely difficult, but in the
last few years there has been an explosion of interest in the use of techniques
adapted from conventional liquid state nuclear magnetic resonance (NMR)
experiments to build small quantum computers. After a brief introduction to
quantum computing I will review the current state of the art, describe some of
the topics of current interest, and assess the long term contribution of NMR
studies to the eventual implementation of practical quantum computers capable
of solving real computational problems.Comment: 8 pages pdf including 6 figures. Perspectives article commissioned by
PhysChemCom
Using Quantum Computers for Quantum Simulation
Numerical simulation of quantum systems is crucial to further our
understanding of natural phenomena. Many systems of key interest and
importance, in areas such as superconducting materials and quantum chemistry,
are thought to be described by models which we cannot solve with sufficient
accuracy, neither analytically nor numerically with classical computers. Using
a quantum computer to simulate such quantum systems has been viewed as a key
application of quantum computation from the very beginning of the field in the
1980s. Moreover, useful results beyond the reach of classical computation are
expected to be accessible with fewer than a hundred qubits, making quantum
simulation potentially one of the earliest practical applications of quantum
computers. In this paper we survey the theoretical and experimental development
of quantum simulation using quantum computers, from the first ideas to the
intense research efforts currently underway.Comment: 43 pages, 136 references, review article, v2 major revisions in
response to referee comments, v3 significant revisions, identical to
published version apart from format, ArXiv version has table of contents and
references in alphabetical orde
Quantum Computing: Pro and Con
I assess the potential of quantum computation. Broad and important
applications must be found to justify construction of a quantum computer; I
review some of the known quantum algorithms and consider the prospects for
finding new ones. Quantum computers are notoriously susceptible to making
errors; I discuss recently developed fault-tolerant procedures that enable a
quantum computer with noisy gates to perform reliably. Quantum computing
hardware is still in its infancy; I comment on the specifications that should
be met by future hardware. Over the past few years, work on quantum computation
has erected a new classification of computational complexity, has generated
profound insights into the nature of decoherence, and has stimulated the
formulation of new techniques in high-precision experimental physics. A broad
interdisciplinary effort will be needed if quantum computers are to fulfill
their destiny as the world's fastest computing devices. (This paper is an
expanded version of remarks that were prepared for a panel discussion at the
ITP Conference on Quantum Coherence and Decoherence, 17 December 1996.)Comment: 17 pages, LaTeX, submitted to Proc. Roy. Soc. Lond. A, minor
correction
NMR Quantum Computation
In this article I will describe how NMR techniques may be used to build
simple quantum information processing devices, such as small quantum computers,
and show how these techniques are related to more conventional NMR experiments.Comment: Pedagogical mini review of NMR QC aimed at NMR folk. Commissioned by
Progress in NMR Spectroscopy (in press). 30 pages RevTex including 15 figures
(4 low quality postscript images
Simulating chemistry using quantum computers
The difficulty of simulating quantum systems, well-known to quantum chemists,
prompted the idea of quantum computation. One can avoid the steep scaling
associated with the exact simulation of increasingly large quantum systems on
conventional computers, by mapping the quantum system to another, more
controllable one. In this review, we discuss to what extent the ideas in
quantum computation, now a well-established field, have been applied to
chemical problems. We describe algorithms that achieve significant advantages
for the electronic-structure problem, the simulation of chemical dynamics,
protein folding, and other tasks. Although theory is still ahead of experiment,
we outline recent advances that have led to the first chemical calculations on
small quantum information processors.Comment: 27 pages. Submitted to Ann. Rev. Phys. Che
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