Optical Quantum Computation

We review the field of Optical Quantum Computation, considering the various implementations that have been proposed and the experimental progress that has been made toward realizing them. We examine both linear and nonlinear approaches and both particle and field encodings. In particular we discuss the prospects for large scale optical quantum computing in terms of the most promising physical architectures and the technical requirements for realizing them

The atmospheric transport of natural and man-made substances

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Valuing the Vulnerable: A Proposed Approach to Cyclical Competency

The competency evaluation system in the United States is in crisis. The criminal justice system has long recognized that a criminal defendant has a right to a fair trial, and being competent to stand trial is a necessary component of that right. Mental illness is increasingly prevalent in our inmate population, and while mental illness and incompetence are not synonymous, the two are often correlated. Unsurprisingly then, competency evaluation requests have skyrocketed in recent years. But importantly, competency is not static. Cycles of compensation and decompensation may require a defendant to go through the competency evaluation system multiple times before they are ever brought to trial. Defendants presenting with this cyclical competency are not uncommon, and Jonathan Mitchell is a prime example. Mitchell’s competency to stand trial has been evaluated at least three different times at three different facilities located all around the United States. When a defendant is deemed incompetent to stand trial, the government may involuntarily medicate that defendant for the purpose of rendering defendant competent to stand trial when the interests of the government outweigh the defendant’s. While involuntarily medicating a criminal defendant is – surprisingly – nothing new in the United States, this case marks the first time that a competent defendant has been so ordered

Comparison of subdominant eigenvalues of some linear search schemes

AbstractThe subdominant eigenvalue of the transition probability matrix of a Markov chain is a determining factor in the speed of transition of the chain to a stationary state. However, these eigenvalues can be difficult to estimate in a theoretical sense. In this paper we revisit the problem of dynamically organizing a linear list. Items in the list are selected with certain unknown probabilities and then returned to the list according to one of two schemes: the move-to-front scheme or the transposition scheme. The eigenvalues of the transition probability matrix Q of the former scheme are well-known but those of the latter T are not. Nevertheless the transposition scheme gives rise to a reversible Markov chain. This enables us to employ a generalized Rayleigh-Ritz theorem to show that the subdominant eigenvalue of T is at least as large as the subdominant eigenvalue of Q

Phase-dependent decoherence of optical transitions in Pr3+:LaF3 in the presence of a driving field

The decoherence times of orthogonally phased components of the optical transition dipole moment in a two-level system have been observed to differ by an order of magnitude. This phase anisotropy is observed in coherent transient experiments where an optical driving field is present during extended periods of decoherence. The decoherence time of the component of the dipole moment in phase with the driving field is extended compared to T_2, obtained from two-pulse photon echoes, in analogy with the spin locking technique of NMR.Comment: 5 pages, 2 figures; replaced with published versio