A Geometrical Derivation of a Family of Quantum Speed Limit Results

We derive a family of quantum speed limit results in time independent systems with pure states and a finite dimensional state space, by using a geometric method based on right invariant action functionals on SU(N). The method relates speed limits for implementing quantum gates to bounds on orthogonality times. We reproduce the known result of the Margolus-Levitin theorem, and a known generalisation of the Margolis-Levitin theorem, as special cases of our method, which produces a rich family of other similar speed limit formulas corresponding to positive homogeneous functions on su(n). We discuss the general relationship between speed limits for controlling a quantum state and a system's time evolution operator.Comment: 12 page

Retrenching the Purse: Finite Exception Logs, and Validating the Small

The Mondex Electronic Purse is an outstanding example of industrial scale formal refinement, and was the first verification to achieve ITSEC level E6 certification. A formal abstract model and a formal concrete model were developed, and a formal refinement was hand-proved between them. Nevertheless, certain requirements issues were set beyond the scope of the formal development, or handled in an unnatural manner. The retrenchment Tower Pattern is used to address one such issue in detail: the finiteness of the purse log (which records unsuccessful transactions). A retrenchment is constructed from the lowest level model of the purse system to a model in which logs are finite, and is then lifted to create two refinement developments of the purse, working at different levels of detail, and connected via retrenchments, forming the tower. The tower development is appropriately validated, vindicating the design used

‘Vrouwen, alcohol en ambiguïteit’[translated from Dutch to English] as 'Women, alcohol and ambivalence'

In welke stad je ’s avonds ook rondwandelt, overal zie je jonge mensen uitgaan, plezier maken en drinken. In de latere uurtjes levert deze mix van jongeren en alcohol vaak dronken en zelfs alarmerende taferelen op. Vrouwen gaan op zo’n momenten op zoek naar het soms wankele evenwicht tussen plezier en controle. "The practices and aesthetics of young women drinking and getting drunk provoke an array of responses. Influenced by psychoanalytic theory, this article explores the negotiation of ambivalent drinking identities centred around ideas of ‘correct’ gendered practices and imaginations, based upon empirical research in Reading (UK) and Groningen (the Netherlands?". (Please note this is not a direct translation of the above abstract)

Local and global models of physics and computation

Classical computation is essentially local in time, yet some formulations of physics are global in time. Here I examine these differences, and suggest that certain forms of unconventional computation are needed to model physical processes and complex systems. These include certain forms of analogue computing, massively parallel field computing, and self-modifying computations

Actual Harm Means it is too Late: How Rosenbach v. Six Flags Demonstrates Effective Biometric Information Privacy Law

Technology is rapidly advancing, and the law is trying to keep up. While this challenge is not new, technological advancements are impacting privacy rights in unprecedented ways. Using a fingerprint to clock in at work or face identification to unlock a smartphone provides ease and convenience, but at what cost? Currently, there is no federal law that regulates the collection, use, and storage of biometric information in the private sector. On a local level, three states have enacted laws that specifically address biometrics. Of those, the Biometric Information Privacy Act (BIPA) in Illinois provides the strongest protections for consumers, who are entitled to a private right of action under the statute. Since the enactment of BIPA about a decade ago, hundreds of plaintiffs have brought legal action against companies operating in Illinois. This Comment explains how the Illinois Supreme Court properly applied the state’s biometric information privacy statute and why the ruling in Rosenbach v. Six Flags should be a model for analyzing biometric information privacy rights. Part II will provide a brief history of privacy law in the United States and how the ubiquitous collection and use of biometric information threatens privacy rights. Next, Part III will describe the facts, issue, and holding of Rosenbach v. Six Flags. Part IV will analyze the court’s examination of statutory language and legislative intent and explain how those findings lay the foundation for future regulation of biometric information. Finally, this Comment will conclude with a recommendation for legislators to rely on Rosenbach as an example of how biometric privacy regulation should apply in states and, one day, nationwide

Eating my words

Language learning is common preparation for much anthropological fieldwork, but the choices researchers make in this area are distinctly political. Prompted by a chance encounter while studying Hindi, the author reflects on this realisation in view of the numerous languages spoken in India, the interactions involved in hospital-based research, and the place of language in Indian politics more broadly

Heating and Cooling of Hot Accretion Flows by Non Local Radiation

We consider non-local effects which arise when radiation emitted at one radius of an accretion disk either heats or cools gas at other radii through Compton scattering. We discuss three situations: 1. Radiation from the inner regions of an advection-dominated flow Compton cooling gas at intermediate radii and Compton heating gas at large radii. 2. Soft radiation from an outer thin accretion disk Compton cooling a hot one- or two-temperature flow on the inside. 3. Soft radiation from an inner thin accretion disk Compton cooling hot gas in a surrounding one-temperature flow. We describe how previous results are modified by these non-local interactions. We find that Compton heating or cooling of the gas by the radiation emitted in the inner regions of a hot flow is not important. Likewise, Compton cooling by the soft photons from an outer thin disk is negligible when the transition from a cold to a hot flow occurs at a radius greater than some minimum $R_{tr,min}$. However, if the hot flow terminates at $R < R_{tr,min}$, non-local cooling is so strong that the hot gas is cooled to a thin disk configuration in a runaway process. In the case of a thin disk surrounded by a hot one-temperature flow, we find that Compton cooling by soft radiation dominates over local cooling in the hot gas for \dot{M} \gsim 10^{-3} \alpha \dot{M}_{Edd}, and R \lsim 10^4 R_{Schw}. As a result, the maximum accretion rate for which an advection-dominated one-temperature solution exists, decreases by a factor of $\sim 10$, compared to the value computed under an assumption of local energy balance.Comment: LaTeX aaspp.sty, 25 pages, and 6 figures; to appear in Ap

EvoMachina : a novel evolutionary algorithm inspired by bacterial genome reorganisation

EvoMachina is a novel natural computation algorithm, inspired by recent understandings of the processes of genome reorganisation in bacteria and viruses. It has been developed as part of the EU FP7 project EvoEvo, taking inspiration from its biological experiments, and developed to support Living Technology applications. This abstract outlines the conceptual model underlying EvoMachina, its implementation, and a reference application

Augmenting Live Coding with Evolved Patterns

We present a new system for integrating evolutionary processes with live coding. The system is built upon an existing platform called Extramuros, which facilitates network-based collaboration on live coding performances. Our evolutionary approach uses the Tidal live coding language within this platform. The system uses a grammar to parse code patterns and create random mutations that conform to the grammar, thus guaranteeing that the resulting pattern has the correct syntax. With these mutations available, we provide a facility to integrate them during a live performance. To achieve this, we added controls to the Extramuros web client that allows coders to select patterns for submission to the Tidal interpreter. The fitness of the pattern is updated implicitly by the way the coder uses the patterns. In this way, appropriate patterns are continuously generated and selected for throughout a performance. We present examples of performances, and discuss the utility of this approach in live coding music