Decoding Across the Quantum LDPC Code Landscape

We show that belief propagation combined with ordered statistics post-processing is a general decoder for quantum low density parity check codes constructed from the hypergraph product. To this end, we run numerical simulations of the decoder applied to three families of hypergraph product code: topological codes, fixed-rate random codes and a new class of codes that we call semi-topological codes. Our new code families share properties of both topological and random hypergraph product codes, with a construction that allows for a finely-controlled trade-off between code threshold and stabilizer locality. Our results indicate thresholds across all three families of hypergraph product code, and provide evidence of exponential suppression in the low error regime. For the Toric code, we observe a threshold in the range $9.9\pm0.2\%$. This result improves upon previous quantum decoders based on belief propagation, and approaches the performance of the minimum weight perfect matching algorithm. We expect semi-topological codes to have the same threshold as Toric codes, as they are identical in the bulk, and we present numerical evidence supporting this observation.Comment: The code for the BP+OSD decoder used in this work can be found on Github: https://github.com/quantumgizmos/bp_os

Organizational Deviance: A Humanist View

The sociological paradigm proposed by C. Wright Mills is advocated as a basis (model) for the study of elite deviance of an organizational nature. The relationship between social structure and social character within organizational environments is examined utilizing central concepts regarding both social character (i.e., alienation, other-directedness, and inauthenticity) and bureaucratic structural characteristics (e.g., routinization and fragmentation of tasks, dehumanization and groupthink, the construction of guilt neutralizing ideologies, and front activities). The paper concludes with a discussion of the implications of this approach for a humanist study of crime

Review of \u3cem\u3eTo Render a Life: Let us Now Praise Famous Men and the Documentary Vision.\u3c/em\u3e Reviewed by David R. Simon, U.C. Berkeley & San Diego State University

To Render A Life: LET US NOW PRAISE FAMOUS MEN And The Documentary Vision (1992) and Long Shadows: The Legacy of the American Civil War (1992). Both by the JAMES AGEE FILM PROJECT, 316 E. Main Street, Johnson City, TN 37601 Phone: (615) 926-8637

Recent Decisions

Antitrust--Act of State Doctrine Precludes Judicial Review of Cases in which Private Defendant Induces Foreign Sovereign to Boycott Plaintiff\u27s Services and Products David R. Simon Plaintiff, a designer and manufacturer of short takeoff and landing (STOL) aircraft, sought damages from defendants for violation of sections 1 and 2 of the Sherman Act. Specifically, plaintiff alleged that defendant\u27s employees falsely disparaged General Aircraft Corporation\u27s (GAC) STOL aircraft products and services by circulating false and misleading performance reports and engaged in a vendetta designed to drive GAC out of business because of GAC\u27s refusal to conduct Southeast Asian Helio sales under the auspices of defendant Doole and Air American. Plaintiff asserted that in furtherance of this vendetta, Air Asia obtained GAC proprietary data and trade secrets that enabled the defendant to fabricate Hello planes and parts without license at its repair facilities in Taiwan from 1962 to January 31, 1975. Finally, plaintiff alleged that defendant orchestrated a boycott of GAC\u27s STOL aircraft, thereby completing the conspiracy to destroy GAC\u27s competitive position in the marketplace. ==================================== Sovereign Immunity-- Act of State Doctrine--Claim Lies for Iran\u27s Failure to Compensate Following Nationalization David D. Dowd Plaintiffs, three corporations collectively representing American insurance interests in Iran in 1979, filed a motion for partial summary judgment on the issue of liability in an action for damages brought in response to the nationalization without compensation of plaintiffs\u27 Iranian insurance interests by defendants Islamic Republic of Iran and Central Insurance of Iran (CII). This nationalization severed all business relations between plaintiffs, defendants, and those Iranian insurance companies in which plaintiffs had invested. Plaintiffs claimed this nationalization provided no mechanism for adequate compensation in violation of the Treaty of Amity and, independently, international law. Defendants argued that either the act of state doctrine or sovereign immunity precluded the court from awarding partial summary judgment. On plaintiffs\u27 motion for partial summary judgment on liability under the Treaty of Amity and international law, granted

Hyperspectral classification of Cyperus esculentus clones and morphologically similar weeds

Cyperus esculentus (yellow nutsedge) is one of the world's worst weeds as it can cause great damage to crops and crop production. To eradicate C. esculentus, early detection is key-a challenging task as it is often confused with other Cyperaceae and displays wide genetic variability. In this study, the objective was to classify C. esculentus clones and morphologically similar weeds. Hyperspectral reflectance between 500 and 800 nm was tested as a measure to discriminate between (I) C. esculentus and morphologically similar Cyperaceae weeds, and between (II) different clonal populations of C. esculentus using three classification models: random forest (RF), regularized logistic regression (RLR) and partial least squares-discriminant analysis (PLS-DA). RLR performed better than RF and PLS-DA, and was able to adequately classify the samples. The possibility of creating an affordable multispectral sensing tool, for precise in-field recognition of C. esculentus plants based on fewer spectral bands, was tested. Results of this study were compared against simulated results from a commercially available multispectral camera with four spectral bands. The model created with customized bands performed almost equally well as the original PLS-DA or RLR model, and much better than the model describing multispectral image data from a commercially available camera. These results open up the opportunity to develop a dedicated robust tool for C. esculentus recognition based on four spectral bands and an appropriate classification model

Meteorology of Jupiter's Equatorial Hot Spots and Plumes from Cassini

We present an updated analysis of Jupiter's equatorial meteorology from Cassini observations. For two months preceding the spacecraft's closest approach, the Imaging Science Subsystem (ISS) onboard regularly imaged the atmosphere. We created time-lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes. Hot spots are quasi-stable, rectangular dark areas on visible-wavelength images, with defined eastern edges that sharply contrast with surrounding clouds, but diffuse western edges serving as nebulous boundaries with adjacent equatorial plumes. Hot spots exhibit significant variations in size and shape over timescales of days and weeks. Some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots. Strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots. Impressive, bright white plumes occupy spaces in between hot spots. Compact cirrus-like 'scooter' clouds flow rapidly through the plumes before disappearing within the dark areas. These clouds travel at 150-200 m/s, much faster than the 100 m/s hot spot and plume drift speed. This raises the possibility that the scooter clouds may be more illustrative of the actual jet stream speed at these latitudes. Most previously published zonal wind profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip. If a downward branch of an equatorially-trapped Rossby waves controls the overall appearance of hot spots, however, the westward phase velocity of the wave leads to underestimates of the true jet stream speed.Comment: 33 pages, 11 figures; accepted for publication in Icarus; for supplementary movies, please contact autho

Hierarchical strategies for efficient fault recovery on the reconfigurable PAnDA device

A novel hierarchical fault-tolerance methodology for reconfigurable devices is presented. A bespoke multi-reconfigurable FPGA architecture, the programmable analogue and digital array (PAnDA), is introduced allowing fine-grained reconfiguration beyond any other FPGA architecture currently in existence. Fault blind circuit repair strategies, which require no specific information of the nature or location of faults, are developed, exploiting architectural features of PAnDA. Two fault recovery techniques, stochastic and deterministic strategies, are proposed and results of each, as well as a comparison of the two, are presented. Both approaches are based on creating algorithms performing fine-grained hierarchical partial reconfiguration on faulty circuits in order to repair them. While the stochastic approach provides insights into feasibility of the method, the deterministic approach aims to generate optimal repair strategies for generic faults induced into a specific circuit. It is shown that both techniques successfully repair the benchmark circuits used after random faults are induced in random circuit locations, and the deterministic strategies are shown to operate efficiently and effectively after optimisation for a specific use case. The methods are shown to be generally applicable to any circuit on PAnDA, and to be straightforwardly customisable for any FPGA fabric providing some regularity and symmetry in its structure