Performance of polar codes for quantum and private classical communication

We analyze the practical performance of quantum polar codes, by computing rigorous bounds on block error probability and by numerically simulating them. We evaluate our bounds for quantum erasure channels with coding block lengths between 2^10 and 2^20, and we report the results of simulations for quantum erasure channels, quantum depolarizing channels, and "BB84" channels with coding block lengths up to N = 1024. For quantum erasure channels, we observe that high quantum data rates can be achieved for block error rates less than 10^(-4) and that somewhat lower quantum data rates can be achieved for quantum depolarizing and BB84 channels. Our results here also serve as bounds for and simulations of private classical data transmission over these channels, essentially due to Renes' duality bounds for privacy amplification and classical data transmission of complementary observables. Future work might be able to improve upon our numerical results for quantum depolarizing and BB84 channels by employing a polar coding rule other than the heuristic used here.Comment: 8 pages, 6 figures, submission to the 50th Annual Allerton Conference on Communication, Control, and Computing 201

Channelization architecture for wide-band slow light in atomic vapors

We propose a ``channelization'' architecture to achieve wide-band electromagnetically induced transparency (EIT) and ultra-slow light propagation in atomic Rb-87 vapors. EIT and slow light are achieved by shining a strong, resonant ``pump'' laser on the atomic medium, which allows slow and unattenuated propagation of a weaker ``signal'' beam, but only when a two-photon resonance condition is satisfied. Our wideband architecture is accomplished by dispersing a wideband signal spatially, transverse to the propagation direction, prior to entering the atomic cell. When particular Zeeman sub-levels are used in the EIT system, then one can introduce a magnetic field with a linear gradient such that the two-photon resonance condition is satisfied for each individual frequency component. Because slow light is a group velocity effect, utilizing differential phase shifts across the spectrum of a light pulse, one must then introduce a slight mismatch from perfect resonance to induce a delay. We present a model which accounts for diffusion of the atoms in the varying magnetic field as well as interaction with levels outside the ideal three-level system on which EIT is based. We find the maximum delay-bandwidth product decreases with bandwidth, and that delay-bandwidth product ~1 should be achievable with bandwidth ~50 MHz (~5 ns delay). This is a large improvement over the ~1 MHz bandwidths in conventional slow light systems and could be of use in signal processing applications.Comment: Published in SPIE Proceedings, Photonics West 2005 (San Jose, CA, Jan. 22-27, 2005

The impact of transformational leadership on the job satisfaction of certified athletic trainers in the NCAA Division I setting

The Purpose of this study is to determine the impact of transformational leadership behaviors of Head Athletic Trainers (HATC\u27s) of Division I, NCAA institutions, and identify how these practices affect the job satisfaction of the subordinate certified athletic trainers (ATC\u27s) in their departments. This was done by looking at the five leadership practices of the HATC\u27s as identified by the Leadership Practice Inventory (LPI) by Kouzes and Posner, and the job satisfaction of the subordinate certified athletic trainers using the Job Satisfaction Survey (JSS) by Spector. The surveys were sent by email to 1,110 ATC\u27s at Division I institutions, where they were asked to evaluate the leadership behaviors of their HATC\u27s with the LPI-Observer, and then to fill out the JSS to show their current satisfaction with their job. Participants were also asked to fill out basic demographic information on employment position, sex, ethnicity, age, and years of experience.The findings show that HATC\u27s in this setting use the leadership practice of enabling others to act significantly more than the others, the practice of inspiring a shared vision significantly less than the others, while modeling the way was significantly more than encouraging the heart, and challenging the process. The results of overall job satisfaction found that ATC\u27s in this setting were more satisfied with their jobs than the norms presented by Spector, but less satisfied than those reported of the Southeastern Conference by Barrett, et. al. Lastly it was found that particular leadership practices strongly correlated with certain facets of job satisfaction. The practice of enabling others to act was a predictor of satisfaction with the facets of promotion, supervision, fringe benefits, contingent rewards, operating conditions, and nature of work. Encouraging the heart was a predictor of satisfaction with pay, and contingent rewards.Modeling the way was a predictor of satisfaction with supervision, co-workers, nature of work, and communication. Challenging the process was found to be a predictor of satisfaction with promotion, supervision, and coworkers. The least used leadership practice of inspiring a shared vision was not found to be a predictor of any facets

Synthesis and application of stereogenic nitrogen-containing ammonium salts as phase-transfer catalysts

The chirality of nitrogen was at the forefront of chemistry over 110 years ago. Since then it has been widely under-acknowledged as a potential chirality source in organic synthesis. This thesis demonstrates the diastereoselective formation of stereogenic nitrogen-containing ammonium salts. Over 150 compounds were synthesised and employed as phase-transfer catalysts in order to assess the chiral-at-nitrogen influence on the outcome of two common phase-transfer-catalysed reactions. Several X-ray crystal structures of single diastereoisomer chiral-at-nitrogen ammonium salts were isolated as well as the synthesis of a library of secondary and tertiary amines

Magnetically-controlled velocity selection in a cold atom sample using stimulated Raman transitions

We observe velocity-selective two-photon resonances in a cold atom cloud in the presence of a magnetic field. We use these resonances to demonstrate a simple magnetometer with sub-mG resolution. The technique is particularly useful for zeroing the magnetic field and does not require any additional laser frequencies than are already used for standard magneto-optical traps. We verify the effects using Faraday rotation spectroscopy.Comment: 5 pages, 6 figure

Application of Advanced Reservoir Characterization, Simulation, and Production Optimization Strategies to Maximize Recovery in Slope and Basin Clastic Reservoirs, West Texas (Delaware Basin)

The objective of this Class III project is to demonstrate that detailed reservoir characterization of elastic reservoirs in basinal sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover more of the original oil in place by strategic infill-well placement and geologically based enhanced oil recovery. The study focused on the Ford Geraldine unit, which produces from the upper Bell Canyon Formation (Ramsey sandstone). Reservoirs in this and other Delaware Mountain Group fields have low producibility (average recovery <14 percent of the original oil in place) because of a high degree of vertical and lateral heterogeneity caused by depositional processes and post-depositional diagenetic modification. Outcrop analogs were studied to better interpret the depositional processes that formed the reservoirs at the Ford Geraldine unit and to determine the dimensions of reservoir sandstone bodies. Facies relationships and bedding architecture within a single genetic unit exposed in outcrop in Culberson County, Texas, suggest that the sandstones were deposited in a system of channels and levees with attached lobes that initially prograded basinward, aggraded, and then stepped around and stepped back toward the shelf. Channel sandstones are 10 to 60 ft thick and 200 to 3,000 ft wide. The flanking levees have a wedge-shaped geometry and are composed of interbedded sandstone and siltstone; thickness varies from 3 to 20 ft and length from several hundred to several thousands of feet. The lobe sandstones are broad lens-shaped bodies; thicknesses range up to 30 ft with aspect ratios (width/thickness) of 100 to 10,000. Lobe sandstones may be interstratified with laminated siltstones.Bureau of Economic Geolog

True-Time Delay Steering of Phased Array Radars Using Slow Light

Application of slow light linear delay to squint-free (true-time delay) steering of phased array radar antennae is discussed. Theoretical analysis is provided on true-time delay radar requirements, including delay precision, amplitude precision, and bandwidth. We also discuss an improvement to the slow light technique based on stimulated Brillouin scattering by using a Faraday rotator mirror that provides temporally stable, linear (with pump power) delay, applicable to practical implementations. Future directions are considered

O-mannosylation in Candida albicans enables development of interkingdom biofilm communities

Peer reviewedPublisher PD