Boundary breathers in the sinh-Gordon model

We present an investigation of the boundary breather states of the sinh-Gordon model restricted to a half-line. The classical boundary breathers are presented for a two parameter family of integrable boundary conditions. Restricting to the case of boundary conditions which preserve the \phi --> -\phi symmetry of the bulk theory, the energy spectrum of the boundary states is computed in two ways: firstly, by using the bootstrap technique and subsequently, by using a WKB approximation. Requiring that the two descriptions of the spectrum agree with each other allows a determination of the relationship between the boundary parameter, the bulk coupling constant, and the parameter appearing in the reflection factor derived by Ghoshal to describe the scattering of the sinh-Gordon particle from the boundary.Comment: 16 pages amslate

Supersymmetric D-brane Bound States with B-field and Higher Dimensional Instantons on Noncommutative Geometry

We classify supersymmetric D0-Dp bound states with a non-zero B-field by considering T-dualities of intersecting branes at angles. Especially, we find that the D0-D8 system with the B-field preserves 1/16, 1/8 and 3/16 of supercharges if the B-field satisfies the ``(anti-)self-dual'' condition in dimension eight. The D0-branes in this system are described by eight dimensional instantons on non-commutative R^8. We also discuss the extended ADHM construction of the eight-dimensional instantons and its deformation by the B-field. The modified ADHM equations admit a sort of the `fuzzy sphere' (embeddings of SU(2)) solution.Comment: 20 pages, LaTeX file, typos corrected and references adde

Crossing the Line: The Experience of Catalogers on the Reference Desk

Presentation to the Cataloging Norms Interest Group, ALA Midwinter Meeting, 25 January 201

Supporting mental health disclosure decisions: The Honest, Open, Proud programme

The stigma associated with mental health problems leaves many feeling they have to ‘hide’ their difficulties. Supporting them in making disclosure decisions can potentially improve well-being, reduce self-stigma and support recovery processes. In this editorial we discuss the case for interventions designed for this purpose and present one prominent programme: Honest, Open, Proud

Dyons in N=4 Supersymmetric Theories and Three-Pronged Strings

We construct and explore BPS states that preserve 1/4 of supersymmetry in N=4 Yang-Mills theories. Such states are also realized as three-pronged strings ending on D3-branes. We correct the electric part of the BPS equation and relate its solutions to the unbroken abelian gauge group generators. Generic 1/4-BPS solitons are not spherically symmetric, but consist of two or more dyonic components held apart by a delicate balance between static electromagnetic force and scalar Higgs force. The instability previously found in three-pronged string configurations is due to excessive repulsion by one of these static forces. We also present an alternate construction of these 1/4-BPS states from quantum excitations around a magnetic monopole, and build up the supermultiplet for arbitrary (quantized) electric charge. The degeneracy and the highest spin of the supermultiplet increase linearly with a relative electric charge. We conclude with comments.Comment: 33 pages, two figures, LaTex, a footnote added, the figure caption of Fig.2 expanded, one more referenc

The SO(N) principal chiral field on a half-line

We investigate the integrability of the SO(N) principal chiral model on a half-line, and find that mixed Dirichlet/Neumann boundary conditions (as well as pure Dirichlet or Neumann) lead to infinitely many conserved charges classically in involution. We use an anomaly-counting method to show that at least one non-trivial example survives quantization, compare our results with the proposed reflection matrices, and, based on these, make some preliminary remarks about expected boundary bound-states.Comment: 7 pages, Late

Upscaling single unit monomer insertion to synthesize discrete oligomers

As one of the emerging techniques for preparing discrete oligomers, the photo-RAFT single unit monomer insertion (SUMI) process has shown its uniqueness and superiority in the control of both monomer sequence and stereochemistry. However, current precision polymer synthesis techniques are still burdened by the scalability challenges, such as low reaction yields, small product quantities, and long production times. Herein, we successfully established a practical protocol to address scalability problems in the photo-RAFT SUMI processes. A series of discrete oligomers containing up to five monomer units were synthesized in batch and flow reactors by sequential and alternating SUMI of two monomers into a trithiocarbonate RAFT agent under mild reaction conditions and purified by automated flash chromatography. This protocol offers the process with large quantity (grams scale), excellent isolated yields (82%–95% for each step and 59% for five iterations), and short production time (several days for a pentamer). © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1947–1955