Solitary confinement and the U.S. prison boom

Solitary confinement is a harsh form custody involving isolation from the general prison population and highly restricted access to visitation and programs. Using detailed prison records covering 30 years of practices in Kansas (1985–2014), we find solitary confinement is a normal event during imprisonment: 38 percent of whites and 46 percent of blacks experienced solitary confinement during their prison term. Long stays in solitary confinement were rare in the late 1980s with no detectable racial disparities, but a sharp increase in capacity after a new prison opening began an era of long-term isolation that most heavily impacted black young adults. A decomposition analysis indicates the increase in the length of stay in solitary confinement almost entirely explains the growth in the proportion of people held in solitary confinement. Our results provide new evidence of increasingly punitive prison conditions and previously unmeasured forms of inequality during the prison boom.Accepted manuscrip

Coherent states, Path integral, and Semiclassical approximation

Using the generalized coherent states we argue that the path integral formulae for $SU(2)$ and $SU(1,1)$ (in the discrete series) are WKB exact,if the starting point is expressed as the trace of $e^{-iT\hat H}$ with $\hat H$ being given by a linear combination of generators. In our case,WKB approximation is achieved by taking a large ``spin'' limit: $J,K\rightarrow \infty$. The result is obtained directly by knowing that the each coefficient vanishes under the $J^{-1}$($K^{-1}$) expansion and is examined by another method to be legitimated. We also point out that the discretized form of path integral is indispensable, in other words, the continuum path integral expression leads us to a wrong result. Therefore a great care must be taken when some geometrical action would be adopted, even if it is so beautiful, as the starting ingredient of path integral.Comment: latex 33 pages and 2 figures(uuencoded postscript file), KYUSHU-HET-19 We have corrected the proof of the WKB-exactness in the section

The Architecture of Discretion: Implications of the Structure of Sanctions for Racial Disparities, Severity, and Net Widening

About four million people are serving a term of probation, parole, or post-release supervision in the United States. Due to the extensive use of incarceration as a punishment for conditions violations, these community supervision programs are a major factor contributing to mass incarceration and, as this Article shows, can play a significant role in exacerbating racial disparities in the criminal legal system. In recent years, jurisdictions throughout the United States have made reforms to their community supervision programs. A major trend in community supervision reform is the integration of new sanctioning structures, such as “swift and certain” sanctions, for conditions violations. These changes not only introduce new types of sanctions but also redesign the architecture of the sanctioning process and provide a valuable opportunity to study how the contours of discretion affect bias, severity, and frequency in the imposition of sanctions. In this Article, I study a statewide probation reform that implemented swift and certain sanctions. I present new empirical evidence on the impact of two key elements of the structure of discretion: the disaggregation of discretion into multiple decision points and the allocation of discretion among various actors in the decision-making process. In addition, this Article includes the first in-depth empirical analysis of swift and certain sanctions on racial disparities. Using a detailed administrative dataset covering nearly 90,000 probation cases, I find that the introduction of swift and certain sanctioning reforms is associated with a statistically significant increase in the overall rate of incarceration among probationers and a statistically significant decrease in racial disparities in incarceration. The overall increase in incarceration is driven by the imposition of new jail and prison sanctions introduced by the swift and certain reforms. The decrease in racial disparities appears to be driven by the narrowing of racial disparities associated with probation revocations. These results suggest that disaggregating and reallocating points of discretion may reduce racial disparities but can come at the expense of widening the carceral net

Final-state read-out of exciton qubits by observing resonantly excited photoluminescence in quantum dots

We report on a new approach to detect excitonic qubits in semiconductor quantum dots by observing spontaneous emissions from the relevant qubit level. The ground state of excitons is resonantly excited by picosecond optical pulses. Emissions from the same state are temporally resolved with picosecond time resolution. To capture weak emissions, we greatly suppress the elastic scattering of excitation beams, by applying obliquely incident geometry to the micro photoluminescence set-up. Rabi oscillations of the ground-state excitons appear to be involved in the dependence of emission intensity on excitation amplitude.Comment: 4 pages, 4 figures, to appear in Appl. Phys. Let

Impact of heavy hole-light hole coupling on optical selection rules in GaAs quantum dots

We report strong heavy hole-light mixing in GaAs quantum dots grown by droplet epitaxy. Using the neutral and charged exciton emission as a monitor we observe the direct consequence of quantum dot symmetry reduction in this strain free system. By fitting the polar diagram of the emission with simple analytical expressions obtained from k$\cdot$p theory we are able to extract the mixing that arises from the heavy-light hole coupling due to the geometrical asymmetry of the quantum dot.Comment: 4 pages, 2 figure

Current noise of a quantum dot p-i-n junction in a photonic crystal

The shot-noise spectrum of a quantum dot p-i-n junction embedded inside a three-dimensional photonic crystal is investigated. Radiative decay properties of quantum dot excitons can be obtained from the observation of the current noise. The characteristic of the photonic band gap is revealed in the current noise with discontinuous behavior. Applications of such a device in entanglement generation and emission of single photons are pointed out, and may be achieved with current technologies.Comment: 4 pages, 3 figures, to appear in Phys. Rev. B (2005