Continuous Measurement of a Non-Markovian Open Quantum System

Continuous quantum measurement is the backbone of various methods in quantum control, quantum metrology, and quantum information. Here, we present a generalized formulation of dispersive measurement of a complex quantum systems. We describe the complex system as an open quantum system that is strongly coupled to a non-Markovian environment, enabling the treatment of a broad variety of natural or engineered complex systems. The system is monitored via a probe resonator coupled to a broadband (Markovian) reservoir. Based on this model, we derive a formalism of Stochastic Hierarchy Equations of Motion (SHEM) describing the decoherence dynamics of the system conditioned on the measurement record. Furthermore, we demonstrate a spectroscopy method based on weak quantum measurement to reveal the non-Markovian nature of the environment, which we term weak spectroscopy.Comment: Published version, the section on continuous state tomography will be published in a separate manuscrip

Locally Optimal Control of Quantum Systems with Strong Feedback

For quantum systems with high purity, we find all observables that, when continuously monitored, maximize the instantaneous reduction in the von Neumann entropy. This allows us to obtain all locally optimal feedback protocols with strong feedback, and explicit expressions for the best such protocols for systems of size N <= 4. We also show that for a qutrit the locally optimal protocol is the optimal protocol for a given range of control times, and derive an upper bound on all optimal protocols with strong feedback.Comment: 4 pages, Revtex4. v2: published version (some errors corrected

Anisotropic low-temperature piezoresistance in (311)A GaAs two-dimensional holes

We report low-temperature resistance measurements in a modulation-doped, (311)A GaAs two-dimensional hole system as a function of applied in-plane strain. The data reveal a strong but anisotropic piezoresistance whose magnitude depends on the density as well as the direction along which the resistance is measured. At a density of $1.6\times10^{11}$ cm$^{-2}$ and for a strain of about $2\times10^{-4}$ applied along [01$\bar{1}$], e.g., the resistance measured along this direction changes by nearly a factor of two while the resistance change in the [$\bar{2}$33] direction is less than 10% and has the opposite sign. Our accurate energy band calculations indicate a pronounced and anisotropic deformation of the heavy-hole dispersion with strain, qualitatively consistent with the experimental data. The extremely anisotropic magnitude of the piezoresistance, however, lacks a quantitative explanation.Comment: 4 pages. Submitted to Applied Physics Letter

Flexible Buffer Materials to Reduce Contact Resistance in Thermal Insulation Measurements

Thermal insulation test methods approach their lower limits as thermal resistance falls below 0.1 m2⋅K/W. This is the minimum value specified in ASTM C 518 (ASTM International, 2010b) while ASTM C 177 (ASTM International, 2010a) proposes about 0.06 m2⋅K/W. Nevertheless these are the test methods, along with their ISO equivalents, required by Australasian building codes and directed at many products and materials with thermal resistance on the low side of 0.1 m2⋅K/W. Alternatives, such as ASTM E 1530 (ASTM International, 2011), cover much lower resistances but require carefully prepared small specimens and very-high contact pressures and are therefore largely unsuitable for both technical and compliance reasons. For these low resistances, the insulation test methods face large errors because of interface resistance between specimen and the apparatus hot and cold plates. Staying with C 518, the problem can be avoided by using direct measurement of the test specimen surface temperatures, but this is difficult, has its own accuracy issues, and is often impractical for commercial laboratories. This technique is generally used in conjunction with interface materials such as flexible foam between the specimen and the hot and cold plates, to enhance contact and also provide an access path for temperature sensors. The alternative prospect of using these interface materials to ensure good specimen contact has been studied, in conjunction with a simple two-step thermal resistance determination based on the difference between presence and absence of the test specimen. This article presents results of a study using this difference approach for the measurement of 12 highly conducting materials, including sheets of aluminum, phenolic, HDPE, MgO, bonded rubber and cork granules, PMMA, and compressed wood fiber. For each material, repeated measurements have been performed with four different interface or “buffer” materials: PVC, silicone, EVA, and nitrile. Silicone sponge provides the most uniform results, consistent with a measurably lower hysteresis. The difference technique yielded a lower indicated thermal resistance than direct measurement by between 0.003 and 0.01 m2⋅K/W, with some variation depending on the specimen surface characteristics and to a lesser extent on the choice of buffer. Larger differences were associated with bowed, uneven or roughly surfaced specimens. The difference-technique results have greater variability, but they may be seen as better estimates of the actual specimen resistance, as contact resistance is much lower for soft-surface interfaces. An interface resistance of up to 0.01 m2⋅K/W is large enough to be of significance in many thermal measurements

Study of genetic structure of Rutilus frisii kutum in Golestan province coastal waters using microsatellite markers

To determine the genetic diversity of Rutilus frisii kutum, 25 samples were collected from Gharesou and Gorgan-rud rivers in April 2008. The genomic DNA was extracted from the caudal fin using phenol- chloroform method and investigated with 10 microsatellite loci. All the 10 investigated loci were polymorphic and showed variability in the two populations of the rivers. The mean number of allele per locus at population level and the observed heterozygosity ranged from 4 to 13 and 0.22 to 1.00, respectively. The FST value between populations was 0.014 (P<0.05), and the analysis of genetic variation distribution indicated a very high within population variation (99%) while among population variation is low (1%). Highly significant deviation from hardy-Weinberg equilibrium was observed in both populations which can be attributed either to the presence of null alleles or to the genetic bottleneck. The results indicated a high level of genetic variation in this species and we concluded that there is more than one population of Rutilus frisii kutum in Golestan coastal waters

Fillet quality grading of common carp (Cyprinus carpio) by fish size using mathematical equations

Quality grading and nutrition value determination of fish are nowadays necessary for aquatic processing. The present study was conducted to investigate a new, applied and cheap method of fillet quality grading for common carp (Cyprinus carpio) using fish size, based on mathematical equations. For this reason, 61 specimens of cultured market size carp were used and after filleting, their moisture, lipid, protein, energy and ash content were measured. Then, the relationships between proximate composition components of fillet and fillet length were studied. Results showed that there is an inverse linear regression relationship between logarithm of moisture content and logarithm of fish length (P0.05). Regarding the relationship between proximate composition of cultured carp fillets and fillet length machine fish sorting based on fish length and grading of moisture, lipid and energy content is feasible. We also found it feasible to determine type of processing and proximate composition of the prepared common carp

Solar-hydrogen combined heat and power systems for remote area power supply

The focus in this thesis is on solar-hydrogen combined heat and power (CHP) systems for supplying both electrical power and hot water in remote areas. The stand-alone solar-hydrogen system studied uses a photovoltaic array to meet the electrical demand directly to the maximum extent possible. Any surplus is fed to a Proton Exchange Membrane (PEM) electrolyser to produce hydrogen for storage. At later times when there is insufficient supply from the PV array, hydrogen is drawn from the storage and input to a PEM fuel cell to generate electricity to meet the supply deficit. The main hurdles facing solar-hydrogen systems are low round-trip energy efficiency in short-term energy storage applications compared to traditional storage systems like batteries, and high capital cost. The thesis investigates fuel cell heat recovery in the context of the complete solar-hydrogen system with the aims of increasing the overall system energy efficiency, and hence improving system economics. An advanced simulation model based on Visual Pascal for sizing and performing techno-economic analysis on the performance of solar-hydrogen CHP systems has been developed. Individual analyses on the system components, energy and cost analyses, waste recovery analysis, and economic optimisation of the system are some of the key capabilities of the model. The techno-economic characteristics of a remote area power supply system for a typical remote household in south-eastern Australia with a nominal 5 kWh daily demand profile have been investigated using the model. Optimal sizing of the fuel cell yields an 8% improvement in the average annual efficiency in power production, and a 12% reduction in the unit cost of electricity generated. Also the recovery of heat from the fuel cell for water heating increases the average annual energy efficiency of the optimally-sized fuel cell from around 40% in electrical power production to about 65% in a CHP application. The value of the recovered heat when used for domestic hot water supply is estimated to be equivalent to more than 10% of the overall cost of the system. The technical feasibility of using a solar-hydrogen system in CHP mode and the economic viability of this option are confirmed by performing an experimental investigation on a 500 W water-cooled PEM fuel cell system. The experimental study also showed that the stoichiometry of the input air, and the fuel cell operating temperature influence the overall performance of the solar-hydrogen CHP system significantly. The findings from this study will assist in the development of a cost-effective solar-hydrogen system for remote applications suitable for future commercialisation

Capability framework for sustainable manufacturing of sports apparel and footwear

The sporting goods sector is characterized by large volumes of production, high levels of consumption and short product life cycles resulting in high disposal rates and waste. Manufacturing of sports products is distributed globally through tier-based supply chains and complex logistics systems. Companies within such supply chains have different levels of capability in sustainable manufacturing, which impacts on the sustainability of the overall business. Reducing environmental impacts is of particular concern for companies at present, due to heightened requirements for the reduction of energy and water consumption, waste and greenhouse gas (GHG) emissions. This article describes outcomes of a research project conducted in collaboration with a global sporting goods manufacturer that focused on the development of relevant capabilities across their supply chain for sustainable manufacturing of sports apparel and footwear. The article presents the developed sustainable manufacturing framework and capability assessment results obtained for selected companies within the supply chain of this global manufacturer in Asia

Inhibitory impacts of natural antioxidants (ascorbic and citric acid) and vacuum packaging on lipid oxidation in frozen Persian sturgeon fillets

This study was aimed to investigate effects of aqueous citric acid (CA) and ascorbic acid (AA) on lipid oxidation in comparison with effect of vacuum packaging in order to find better treatment to delay improper changes in the Persian sturgeon (Acipenser persicus) fillets during frozen storage due to lipid oxidation. In this study traditional packaging, vacuum packaging, ascorbic acid solution (0.5 %) and citric acid solution (0.5 %) were considered as treatments. Rancidity development was measured by several biochemical indicators including Free Fatty Acids, Peroxide values and Thiobarbituric acid. Also pH, expressible moisture and sensory properties were measured during 6 months storage. Results showed that free fatty acid (FFA), primary and secondary oxidation products of control samples were significantly higher than those in other treatments (p<0.05). Also, expressible moisture and pH value of treated samples were significantly lower than those in control (p<0.05). However both antioxidants (AA and CA) extended shelf life of frozen fillets but rancidity development in CA treated samples was higher than other samples during storage. Results showed that all three treatments had significant effect on delaying lipid oxidation (p<0.05) but usage of AA and vacuum packaging had the best effect on delaying lipid oxidation and increasing shelf-life of fillets (p<0.05) . Thus the employment of AA and vacuum packaging alone or in combination with other protective strategies is recommended