Entanglement Generation of Clifford Quantum Cellular Automata

Clifford quantum cellular automata (CQCAs) are a special kind of quantum cellular automata (QCAs) that incorporate Clifford group operations for the time evolution. Despite being classically simulable, they can be used as basic building blocks for universal quantum computation. This is due to the connection to translation-invariant stabilizer states and their entanglement properties. We will give a self-contained introduction to CQCAs and investigate the generation of entanglement under CQCA action. Furthermore, we will discuss finite configurations and applications of CQCAs.Comment: to appear in the "DPG spring meeting 2009" special issue of Applied Physics

Harnessing solar energy using photosynthetic and organic pigments.

"Fossil fuels are a finite energy resource that must be supplemented or replaced by more stable forms of electrical energy. Solar technology research strives to supplement and provide eventual replacement for fossil fuel technology. This experiment focused on the use of natural pigments as photo-sensitizers in the current generation of solar cells called dye sensitized solar cells (DSSCs). Pigments from purified chlorophyll a, chlorophyll b, chlorophyll a/b, crude spinach (Spinacia oleracea) extract, phycocyanin, and chlorophyllin were used to construct DSSCs and evaluated, along with a control containing no pigment, for solar energy conversion. The anode of the solar cells consisted of titanium dioxide (TiO2) plates soaked in pigment solutions for twenty-four hours. The plates were assembled, along with an electrolyte sandwiched between cells, and a platinum-coated counter plate that functioned as the cathode. A gasket seal was placed between the plates and held together with rubber bands. The DSSCs were each tested for a maximum power (Pmax) point and a resistor was selected that corresponded to the resistance at that point. The cells were randomly placed into a power block assembly located in an environmental chamber with lighting that provided an average of 27,590 lumens at the surface of DSSCs. With appropriate resistors in place, the cells were subjected to twelve-hour days and twelve-hour nights for ten days, and measurements were recorded every ten minutes. Data were collected to obtain values for voltage in millivolts (mV), current in microamps (æA), and power in microwatts (æW), as well as beginning and ending efficiencies in converting light to usable energy. Voltages were substantially higher during the day than at night for all pigments, except for the control, indicating that the pigments functioned as DSSCs. Hence, only daytime values were used for data analysis. Voltage during the ten-day experiment ranged from 3.99 to 274 mV; current ranged from 0.0180 to 41.9 æA, and power ranged from 0.00 to 11.3 æW. Chlorophyllin had the highest peak and least voltage (274 and 161 mV), highest peak and least current (41.9 and 21.8 æA), and highest peak and least power (11.3 and 4.84 æW). The ranking of the pigments for peak voltage was: Chlorophyllin = Crude Extract ; Chlorophyll a = Chlorophyll a/b ; Phycocyanin = Chlorophyll b > Control. The ranking for least voltage was: Chlorophyllin > Phycocyanin ; Chlorophyll a/b ; Crude Extract ; Chlorophyll b ; Chlorophyll a ; Control. Ranking for peak and least values were similar for current and power. Solar energy conversion (efficiency in converting light energy to usable energy in watts per square meter) for all treatments ranged from 0.000595 to 0.0217% at the beginning of the experiment, and was highest in cells constructed with chlorophyllin. Based on rankings from peak and ending voltage values, as well as other measurements, it was concluded that DSSCs constructed with chlorophyllin performed the best and lasted the longest as photo-sensitizers, compared to other pigments used in this investigation. The DSSCs constructed with crude extract performed almost as well as those constructed with chlorophyllin at the beginning of the experiment, but degradation of this naturally-made pigment may have prevented these cells from sustaining solar energy conversion for more than a few days. Other pigments demonstrated conversion values higher than those of control DSSCs which contained no pigments. The results from this project provide evidence that DSSCs can produce useable energy. More research is needed to enhance and prolong the efficiency of DSSCs in solar energy conversion."--Abstract.

Rapid and robust spin state amplification

Electron and nuclear spins have been employed in many of the early demonstrations of quantum technology (QT). However applications in real world QT are limited by the difficulty of measuring single spins. Here we show that it is possible to rapidly and robustly amplify a spin state using a lattice of ancillary spins. The model we employ corresponds to an extremely simple experimental system: a homogenous Ising-coupled spin lattice in one, two or three dimensions, driven by a continuous microwave field. We establish that the process can operate at finite temperature (imperfect initial polarisation) and under the effects of various forms of decoherence.Comment: 5 pages, 2 figure

Exploring the creation of a digital resource to support the learning of undergraduate students of L2 French and L3 Spanish

The research presented in this thesis focuses on the development of a bespoke online resource to support the learning of undergraduate students with English as their native language (L1), studying French as their first foreign language (L2) and Spanish as their second (L3). It explores the experiences of both staff and student members of a university department of Modern Languages, and contextualises the data by drawing upon theories of cross-linguistic influence (CLI) and metalinguistic awareness (MA). Simultaneously, this collaboration is analysed in the context of the development of a language-learning community, to determine whether it can be deemed the endeavour of a Community of Practice (Wenger, 1998). The research uses an Action Research approach, employing a sequence of interviews and focus groups to generate data relating to linguistic aspects of L2 French and L3 Spanish language-learning, as well as pedagogical and practical considerations in the design of the resource. The emerging data are scrutinised through thematic analysis. The prototype e-learning resource is piloted by student participants, who subsequently engage in a debriefing process to evaluate its effectiveness. The evidence confirms that students of L2 French and L3 Spanish felt the benefit of working with a bespoke resource addressing their specific learning experiences and needs. They demonstrated MA in their engagement with materials focusing on areas identified as potential sources of CLI. There was also evidence of a heightened sense of community identity in this enterprise, which the study concludes as being an example of a collectivity of practice (Lindkvist, 2005). The project proposes a living educational theory, which is articulated before and after the study and evolves as a result of the research conducted. The theory stresses the appropriateness of collaborative endeavour in the context of the study, and contends in the conclusion that through collective activity in a language-learning domain, a sharing of ideas and understanding can exist and be developed. In its focus on developing an online learning resource to support the specific audience of English L1 students learning L2 French and L3 Spanish, and achieving this by harnessing a language-learning community to pinpoint lived and living experiences of CLI and MA, this study addresses a gap in professional practice. Its findings are presented both as a contribution to the teaching and learning of Modern Languages, and as a stimulus for further research and development in the field of bespoke resource design for students simultaneously engaging with L2 and L3 studies. The innovative approach, embracing sequenced input from staff and students and drawing on both learning experiences and relevant theories, offers transferability to different language combinations, and to other language-learning settings across the HE sector

Scotland's aquifers and groundwater bodies

Scotland’s groundwater is a highly valuable resource. The volume of groundwater is greater than the water found in our rivers and lochs, but is hidden from sight beneath our feet. Groundwater underpins Scotland’s private drinking water supplies and provides reliable strategic public water supply to many rural towns; it also sustains the bottled water and whisky industries and is relied upon for irrigation by many farmers. Groundwater also provides many important environmental functions, providing at least 30% of the flow in most Scottish rivers, and maintaining many precious ecosystems. Groundwater management in Scotland is delivered primarily through the River Basin Management framework. Groundwater bodies are a key component of this, defining areas of groundwater that behave in a similar way, both naturally and in response to pressures from human activity. Groundwater bodies provide a risk-based framework for prioritising action to remediate problems, and preventing new problems. Scottish groundwater bodies have undergone a major review for the second River Basin Management cycle, using the latest geological information from the British Geological Survey (BGS), and improved experience of groundwater management from the Scottish Environment Protection Agency (SEPA). A key new development is the separation of groundwater bodies into two layers: a shallow layer of superficial groundwater bodies, and a deep layer of bedrock groundwater bodies. This is important in order to help target action. Shallow groundwater bodies are more at risk from activities such as agriculture, whilst deeper bodies are more at risk from activities such as mining. This report provides a summary of the results of the review, which has been a collaborative project by BGS and SEPA. It documents the process of how the groundwater bodies and aquifers of Scotland were defined, and describes the hydrogeology of each of the main aquifers. The report can therefore be used as a technical introduction to the hydrogeology of Scotland. The two maps overleaf illustrate Scotland’s aquifers and the latest iteration of groundwater bodies as developed during this project

The effect of cylinder liner operating temperature on frictional loss and engine emissions in piston ring conjunction

Despite extensive research into alternative methods, the internal combustion engine is expected to remain as the primary source of vehicular propulsion for the foreseeable future. There are still significant opportunities for improving fuel efficiency, thus directly reducing the harmful emissions. Consequently, mitigation of thermal and frictional losses has gradually become a priority. The piston-cylinder system accounts for the major share of all the losses as well as emissions. Therefore, the need for an integrated approach, particularly of a predictive nature is essential. This paper addresses this issue, particularly the role of cylinder liner temperature, which affects both thermal and frictional performance of the piston-cylinder system. The study focuses on the top compression ring whose critical sealing function makes it a major source of frictional power loss and a critical component in guarding against further blow-by of harmful gasses. Such an integrated approach has not hitherto been reported in literature. The study shows that the cylinder liner temperature is critical in mitigating power loss as well as reducing Hydrocarbon (HC) and Nitrogen Oxide (NOx) emissions from the compression ring – cylinder liner conjunction. The results imply the existence of an optimum range for liner working temperature, independent of engine speed (at least in the studied cases) to minimise frictional losses. Combined with the study of NOx and HC emissions, the control of liner temperature can help to mitigate frictional power loss and reduce emissions

Urbanization and the Emergence of the Greek Polis: The Case of Azoria, Crete

Perhaps the most striking development accompanying the emergence of the Greek city-state (ca. 1200-480 BC) was the appearance of new urban centers whose form, contents, and construction provided the most visible and effective means of creating, reinforcing, and symbolizing the social, political, and economic relationships that characterized the new polis system. Excavations at the site of Azoria (East Crete) have brought to light an unparalleled collection of architectural data, largely unobscured by later activities, that provides one of the best opportunities to study the architectural correlates of urbanization in the Greek world. This paper explores three levels of the built environment at Azoria - the domestic, the civic, and the urb.an - and demonstrates that the architectural landscape of the nascent city-state not only served to reflect the dramatic social and political developments that accompanied the emergence of the polis, but in effect, also functioned a.s an active agent in their creation

Investigating mechanisms of social support effectiveness: The case of locomotion motivation

Although social support can entail costs, individuals with a higher locomotion orientation, who are motivated to move and take action, benefit from support. In two dyadic studies, we tested whether perceived movement towards important goals would mediate the effect of recipients’ locomotion motivation on positive outcomes in support contexts. In Study 1, couples completed a 10-day diary and then recalled support interactions with their partner after the diary period. In Study 2, couples engaged in laboratory support interactions for important goals. Perceived goal movement mediated the effect of higher (vs. lower) locomotion on self-reported ratings and coder ratings of support outcomes. Higher locomotion recipients may benefit in support contexts because they perceive they can move smoothly towards their goals

Cross-verification of independent quantum devices

Quantum computers are on the brink of surpassing the capabilities of even the most powerful classical computers. This naturally raises the question of how one can trust the results of a quantum computer when they cannot be compared to classical simulation. Here we present a verification technique that exploits the principles of measurement-based quantum computation to link quantum circuits of different input size, depth, and structure. Our approach enables consistency checks of quantum computations within a device, as well as between independent devices. We showcase our protocol by applying it to five state-of-the-art quantum processors, based on four distinct physical architectures: nuclear magnetic resonance, superconducting circuits, trapped ions, and photonics, with up to 6 qubits and 200 distinct circuits