



@article {1355,
	title = {Coherence of an optically illuminated single nuclear spin qubit},
	journal = {Physical Review Letters},
	volume = {100},
	year = {2008},
	month = {2008/2/19},
	abstract = {We investigate the coherence properties of individual nuclear spin quantum bits in diamond [Dutt et al., Science, 316, 1312 (2007)] when a proximal electronic spin associated with a nitrogen-vacancy (NV) center is being interrogated by optical radiation. The resulting nuclear spin dynamics are governed by time-dependent hyperfine interaction associated with rapid electronic transitions, which can be described by a spin-fluctuator model. We show that due to a process analogous to motional averaging in nuclear magnetic resonance, the nuclear spin coherence can be preserved after a large number of optical excitation cycles. Our theoretical analysis is in good agreement with experimental results. It indicates a novel approach that could potentially isolate the nuclear spin system completely from the electronic environment.
},
	doi = {10.1103/PhysRevLett.100.073001},
	url = {http://arxiv.org/abs/0707.1341v2},
	author = {Liang Jiang and M. V. Gurudev Dutt and Emre Togan and Lily Childress and Paola Cappellaro and J. M. Taylor and Mikhail D. Lukin}
}
@article {1194,
	title = {Signatures of incoherence in a quantum information processor},
	year = {2007},
	month = {2007/05/24},
	abstract = {  Incoherent noise is manifest in measurements of expectation values when the
underlying ensemble evolves under a classical distribution of unitary
processes. While many incoherent processes appear decoherent, there are
important differences. The distribution functions underlying incoherent
processes are either static or slowly varying with respect to control
operations and so the errors introduced by these distributions are refocusable.
The observation and control of incoherence in small Hilbert spaces is well
known. Here we explore incoherence during an entangling operation, such as is
relevant in quantum information processing. As expected, it is more difficult
to separate incoherence and decoherence over such processes. However, by
studying the fidelity decay under a cyclic entangling map we are able to
identify distinctive experimental signatures of incoherence. This result is
demonstrated both through numerical simulations and experimentally in a three
qubit nuclear magnetic resonance implementation.
},
	url = {http://arxiv.org/abs/0705.3666v2},
	author = {Michael K. Henry and Alexey V. Gorshkov and Yaakov S. Weinstein and Paola Cappellaro and Joseph Emerson and Nicolas Boulant and Jonathan S. Hodges and Chandrasekhar Ramanathan and Timothy F. Havel and Rudy Martinez and David G. Cory}
}
