Calculation of compressible turbulent boundary layers with pressure gradients and heat transfer

Calculation of compressible turbulent boundary layers with pressure gradients and heat transfe

Reconceptualising Personas Across Cultures: Archetypes, Stereotypes & Collective Personas in Pastoral Namibia

The paucity of projects where persona is the research foci and a lack of consensus on this artefact keep many reticent about its purpose and value. Besides crafting personas is expected to differ across cultures, which contrasts the advancements in Western theory with studies and progress in other sites. We postulate User-Created Personas reveal specific characteristics of situated contexts by allowing laypeople to design persona artefacts in their own terms. Hence analysing four persona sessions with an ethnic group in pastoral Namibia –ovaHerero– brought up a set of fundamental questions around the persona artefact regarding stereotypes, archetypes, and collective persona representations: (1) to what extent user depictions are stereotypical or archetypal? If stereotypes prime (2) to what degree are current personas a useful method to represent end-users in technology design? And, (3) how can we ultimately read accounts not conforming to mainstream individual persona descriptions but to collectives

Entanglement Detection Using Majorization Uncertainty Bounds

Entanglement detection criteria are developed within the framework of the majorization formulation of uncertainty. The primary results are two theorems asserting linear and nonlinear separability criteria based on majorization relations, the violation of which would imply entanglement. Corollaries to these theorems yield infinite sets of scalar entanglement detection criteria based on quasi-entropic measures of disorder. Examples are analyzed to probe the efficacy of the derived criteria in detecting the entanglement of bipartite Werner states. Characteristics of the majorization relation as a comparator of disorder uniquely suited to information-theoretical applications are emphasized throughout.Comment: 10 pages, 1 figur

On circulant states with positive partial transpose

We construct a large class of quantum "d x d" states which are positive under partial transposition (so called PPT states). The construction is based on certain direct sum decomposition of the total Hilbert space displaying characteristic circular structure - that is way we call them circulant states. It turns out that partial transposition maps any such decomposition into another one and hence both original density matrix and its partially transposed partner share similar cyclic properties. This class contains many well known examples of PPT states from the literature and gives rise to a huge family of completely new states.Comment: 15 pages; minor correction

Gravi-Weak Unification and the Black-Hole-Hedgehog's Solution with Magnetic Field Contribution

In the present paper, we investigated the gravitational black-hole-hedgehog's solution with magnetic field contribution in the framework of the f(R)--gravity described by the Gravi-Weak unification model. Assuming the Multiple Point Principle (MPP), we considered the existence of the two degenerate vacua of the Universe: the first Electroweak (EW) vacuum with $v_1 \approx 246$ GeV ("true vacuum"), and the second Planck scale ("false vacuum") with $v_2 \sim 10^{18}$ GeV. In these vacua, we investigated different topological defects. The main aim of this paper is an investigation of the black-hole-hedgehog configurations as defects of the "false vacuum". We have obtained the solution which corresponds to a global monopole, that has been "swallowed" by the black-hole with core mass $M_{BH}\approx 3.65\times 10^{18}\,\, {\rm{GeV}}$ and radius $\delta \approx 6\cdot 10^{-21} {\rm{GeV}}^{-1}.$ We investigated the metric in the vicinity of the black-hole-hedgehog and estimated its horizon radius: $r_h\approx 1.14 \delta$. We have considered the phase transition from the "false vacuum" to the "true vacuum" and confirmed the stability of the EW--vacuum.Comment: 22 pages. arXiv admin note: text overlap with arXiv:1703.05594, arXiv:1801.06979, arXiv:1605.01169; text overlap with arXiv:1002.4275 by other author

Using Qubits to Measure Fidelity in Mesoscopic Systems

We point out the similarities in the definition of the `fidelity' of a quantum system and the generating function determining the full counting statistics of charge transport through a quantum wire and suggest to use flux- or charge qubits for their measurement. As an application we use the notion of fidelity within a first-quantized formalism in order to derive new results and insights on the generating function of the full counting statistics.Comment: 5 pages, 1 figur

Completely positive covariant two-qubit quantum processes and optimal quantum NOT operations for entangled qubit pairs

The structure of all completely positive quantum operations is investigated which transform pure two-qubit input states of a given degree of entanglement in a covariant way. Special cases thereof are quantum NOT operations which transform entangled pure two-qubit input states of a given degree of entanglement into orthogonal states in an optimal way. Based on our general analysis all covariant optimal two-qubit quantum NOT operations are determined. In particular, it is demonstrated that only in the case of maximally entangled input states these quantum NOT operations can be performed perfectly.Comment: 14 pages, 2 figure

A Simple Algorithm for Local Conversion of Pure States

We describe an algorithm for converting one bipartite quantum state into another using only local operations and classical communication, which is much simpler than the original algorithm given by Nielsen [Phys. Rev. Lett. 83, 436 (1999)]. Our algorithm uses only a single measurement by one of the parties, followed by local unitary operations which are permutations in the local Schmidt bases.Comment: 5 pages, LaTeX, reference adde