Bibcode
Laflamme, R.; Knill, E.; Cory, D. G.; Fortunato, E. M.; Havel, T.; Miquel, C.; Martinez, R.; Negrevergne, C.; Ortiz, G.; Pravia, M. A.; Sharf, Y.; Sinha, S.; Somma, R.; Viola, L.
Referencia bibliográfica
eprint arXiv:quant-ph/0207172
Fecha de publicación:
7
2002
Número de citas
31
Número de citas referidas
25
Descripción
After a general introduction to nuclear magnetic resonance (NMR), we
give the basics of implementing quantum algorithms. We describe how
qubits are realized and controlled with RF pulses, their internal
interactions, and gradient fields. A peculiarity of NMR is that the
internal interactions (given by the internal Hamiltonian) are always on.
We discuss how they can be effectively turned off with the help of a
standard NMR method called ``refocusing''. Liquid state NMR experiments
are done at room temperature, leading to an extremely mixed (that is,
nearly random) initial state. Despite this high degree of randomness, it
is possible to investigate QIP because the relaxation time (the time
scale over which useful signal from a computation is lost) is
sufficiently long. We explain how this feature leads to the crucial
ability of simulating a pure (non-random) state by using ``pseudopure''
states. We discuss how the ``answer'' provided by a computation is
obtained by measurement and how this measurement differs from the ideal,
projective measurement of QIP. We then give implementations of some
simple quantum algorithms with a typical experimental result. We
conclude with a discussion of what we have learned from NMR QIP so far
and what the prospects for future NMR QIP experiments are.