Upper bounds on entangling rates of bipartite Hamiltonians

We discuss upper bounds on the rate at which unitary evolution governed by a non-local Hamiltonian can generate entanglement in a bipartite system. Given a bipartite Hamiltonian H coupling two finite dimensional particles A and B, the entangling rate is shown to be upper bounded by c*log(d)*norm(H), where d is the smallest dimension of the interacting particles, norm(H) is the operator norm of H, and c is a constant close to 1. Under certain restrictions on the initial state we prove analogous upper bound for the ancilla-assisted entangling rate with a constant c that does not depend upon dimensions of local ancillas. The restriction is that the initial state has at most two distinct Schmidt coefficients (each coefficient may have arbitrarily large multiplicity). Our proof is based on analysis of a mixing rate -- a functional measuring how fast entropy can be produced if one mixes a time-independent state with a state evolving unitarily.Comment: 14 pages, 4 figure

Shock-induced separation of adiabatic turbulent boundary layers in supersonic axially symmetric internal flow

An experimental investigation at Mach 4 of shock-induced turbulent boundary layer separation at the walls of axially symmetric flow passages is discussed, with particular emphasis placed on determining the shock strengths required for incipient separation. The shock waves were produced by interchangeable sting-mounted cones placed on the axes of the flow passages and aligned with the freestream flow. The interactions under study simulate those encountered in axially symmetric engine inlets of supersonic aircraft. Knowledges of the shock strengths required for boundary layer separation in inlets is important since for shocks of somewhat greater strength rather drastic alterations in the inlet flow field may occur

Influence of suction on shock wave-turbulent boundary layer interactions for two- dimensional and axially symmetric flows, 16 September 1967 - 30 June 1969

Influence of suction on shock wave turbulent boundary layer interactions for two dimensional and axially symmetric flow

Engineering enterprise through intellectual property education - pedagogic approaches

Engineering faculties, despite shrinking resources, are delivering to new enterprise agendas that must take account of the fuzzying of disciplinary boundaries. Learning and teaching, curriculum design and research strategies reflect these changes. Driven by changing expectations of how future graduates will contribute to the economy, academics in engineering and other innovative disciplines are finding it necessary to re-think undergraduate curricula to enhance students’ entrepreneurial skills, which includes their awareness and competence in respect of intellectual property rights [IPRs]. There is no well established pedagogy for educating engineers, scientists and innovators about intellectual property. This paper reviews some different approaches to facilitating non-law students’ learning about IP. Motivated by well designed ‘intended learning outcomes’ and assessment tasks, students can be encouraged to manage their learning... The skills involved in learning about intellectual property rights in this way can be applied to learning other key, but not core, subjects. At the same time, students develop the ability to acquire knowledge, rather than rely on receiving it, which is an essential competence for a ‘knowledge’ based worker

Numerical Analysis of the Capacities for Two-Qubit Unitary Operations

We present numerical results on the capacities of two-qubit unitary operations for creating entanglement and increasing the Holevo information of an ensemble. In all cases tested, the maximum values calculated for the capacities based on the Holevo information are close to the capacities based on the entanglement. This indicates that the capacities based on the Holevo information, which are very difficult to calculate, may be estimated from the capacities based upon the entanglement, which are relatively straightforward to calculate.Comment: 9 pages, 10 figure

Decoherent quantum walks driven by a generic coin operation

We consider the effect of different unitary noise mechanisms on the evolution of a quantum walk (QW) on a linear chain with a generic coin operation: (i) bit-flip channel noise, restricted to the coin subspace of the QW, and (ii) topological noise caused by randomly broken links in the linear chain. Similarities and differences in the respective decoherent dynamics of the walker as a function of the probability per unit time of a decoherent event taking place are discussed

‘National Resources’? The Fragmented Citizenship of Gas Extraction in Tanzania

Recent discoveries of oil and natural gas across East Africa have provoked a wave of political optimism fuelled by imaginaries of future development. Tanzania is a paragon of this trend; its government having asserted its potential to become a globally significant natural gas producer within a decade. Yet, this rhetorical promise has been countered by a series of violent confrontations that have taken place between state forces and residents of southern Tanzania. Although these struggles are about various articulations of resource sovereignty, this paper argues that they should be located less in questions of resource control, than in a historical marginalisation of the south, or what has been called a ‘hidden agenda’, that privileges urban centres to the north. Drawing on original qualitative data generated over three years in Mtwara and Lindi regions, it shows how gas discoveries reveal the fault lines in the construction of an inclusive ‘Tanzanian’ citizenship. Protesters counter-narrate their sense of citizenship with insurgent strategies ranging from strike action to calls for secession. In short, natural gas discoveries actually extend the fragmentation of an already ‘differentiated citizenship’. Studies of resource conflict and sovereignty, we conclude, should pay more attention to the contested nature of citizenship

Accumulator for shaft encoder

Digital accumulator relies almost entirely on integrated circuitry to process the data derived from the outputs of gyro shaft encoder. After the read command is given, the output register collects and stores the data that are on the set output terminals of the up-down counters

Universal quantum computation by discontinuous quantum walk

Quantum walks are the quantum-mechanical analog of random walks, in which a quantum `walker' evolves between initial and final states by traversing the edges of a graph, either in discrete steps from node to node or via continuous evolution under the Hamiltonian furnished by the adjacency matrix of the graph. We present a hybrid scheme for universal quantum computation in which a quantum walker takes discrete steps of continuous evolution. This `discontinuous' quantum walk employs perfect quantum state transfer between two nodes of specific subgraphs chosen to implement a universal gate set, thereby ensuring unitary evolution without requiring the introduction of an ancillary coin space. The run time is linear in the number of simulated qubits and gates. The scheme allows multiple runs of the algorithm to be executed almost simultaneously by starting walkers one timestep apart.Comment: 7 pages, revte

Application of DOT-MORSE coupling to the analysis of three-dimensional SNAP shielding problems

The use of discrete ordinates and Monte Carlo techniques to solve radiation transport problems is discussed. A general discussion of two possible coupling schemes is given for the two methods. The calculation of the reactor radiation scattered from a docked service and command module is used as an example of coupling discrete ordinates (DOT) and Monte Carlo (MORSE) calculations