Field-induced structure transformation in electrorheological solids

We have computed the local electric field in a body-centered tetragonal (BCT) lattice of point dipoles via the Ewald-Kornfeld formulation, in an attempt to examine the effects of a structure transformation on the local field strength. For the ground state of an electrorheological solid of hard spheres, we identified a novel structure transformation from the BCT to the face-centered cubic (FCC) lattices by changing the uniaxial lattice constant c under the hard sphere constraint. In contrast to the previous results, the local field exhibits a non-monotonic transition from BCT to FCC. As c increases from the BCT ground state, the local field initially decreases rapidly towards the isotropic value at the body-centered cubic lattice, decreases further, reaching a minimum value and increases, passing through the isotropic value again at an intermediate lattice, reaches a maximum value and finally decreases to the FCC value. An experimental realization of the structure transformation is suggested. Moreover, the change in the local field can lead to a generalized Clausius-Mossotti equation for the BCT lattices.Comment: Submitted to Phys. Rev.

Pairwise dwarf galaxy formation and galaxy downsizing: some clues from extremely metal-poor Blue Compact Dwarf galaxies

Some of the extremely metal-poor Blue Compact Dwarf galaxies (XBCDs) in the nearby universe form galaxy pairs with remarkably similar properties. This fact points to an intriguing degree of synchronicity in the formation history of these binary dwarf galaxies and raises the question as to whether some of them form and co-evolve pairwise (or in loose galaxy groups), experiencing recurrent mild interactions and minor tidally induced star formation episodes throughout their evolution. We argue that this hypothesis offers a promising conceptual framework for the exploration of the retarded previous evolution and recent dominant formation phase of XBCDs.Comment: To appear in the proceedings of the JENAM 2010 Symposium "Dwarf Galaxies: Keys to Galaxy Formation and Evolution" (Lisbon, 9-10 September 2010), P. Papaderos, S. Recchi, G. Hensler (eds.), Springer Verlag (2011), in pres

Two-qubit entanglement dynamics for two different non-Markovian environments

We study the time behavior of entanglement between two noninteracting qubits each immersed in its own environment for two different non-Markovian conditions: a high-$Q$ cavity slightly off-resonant with the qubit transition frequency and a nonperfect photonic band-gap, respectively. We find that revivals and retardation of entanglement loss may occur by adjusting the cavity-qubit detuning, in the first case, while partial entanglement trapping occurs in non-ideal photonic-band gap.Comment: 8 pages, 2 figure

Similarity transformations approach for a generalized Fokker-Planck equation

By using similarity transformations approach, the exact propagator for a generalized one-dimensional Fokker-Planck equation, with linear drift force and space-time dependent diffusion coefficient, is obtained. The method is simple and enables us to recover and generalize special cases studied through the Lie algebraic approach and the Green function technique.Comment: 8 pages, no figure

Dilatonic Black Holes, Naked Singularities and Strings

We extend a previous calculation which treated Schwarschild black hole horizons as quantum mechanical objects to the case of a charged, dilaton black hole. We show that for a unique value of the dilaton parameter `a', which is determined by the condition of unitarity of the S matrix, black holes transform at the extremal limit into strings.Comment: 8 pages, REVTE

Academic Library Leadership Issues and Challenges: An Informational Interview with Peter Sidorko, Librarian of the University of Hong Kong

Founded in 1911 during the British Colonial era, with the aim of competing with the other Great Powers opening universities in Mainland China, the University of Hong Kong (HKU) is the oldest tertiary institution in Hong Kong. Supporting the learning, teaching and research needs of the whole University community, the HKU Library is set up with the commitment to develop and deliver a wide range of resources and services dedicated for engaging the users in the efficient use of library resources in all formats. It was the commitment to promoting a strong intellectual environment and IT infrastructure in libraries that brought Peter Sidorko to the HKU Library over 13 years ago. A seasoned librarian with an established career of working in libraries throughout Australia, Peter Sidorko was hired in 2001 as the Deputy Librarian for HKU before becoming the current University Librarian in 2011. In his current position, Peter Sidorko oversees HKU's library network, comprised of one Main Library and six other subject branches that serve a student population of over 27,000. In the following interview, Peter Sidorko discusses the ways in which he uses his participative management style to work closely with staff and faculty in supporting the unique academic environment at HKU. Furthermore, he speaks about the deep collaboration with other university libraries in Hong Kong through organizations such as JULAC (Joint University Librarians Advisory Committee), and other services like HKALL (Hong Kong Academic Library Link). He also openly discusses the current challenges facing the field and the promising goals of supporting the unique collections that have made HKU a world-renowned academic institute.published_or_final_versio