Large-scale magnetic fields from inflation in teleparallel gravity

Generation of large-scale magnetic fields in inflationary cosmology is studied in teleparallelism, where instead of the scalar curvature in general relativity, the torsion scalar describes the gravity theory. In particular, we investigate a coupling of the electromagnetic field to the torsion scalar during inflation, which leads to the breaking of conformal invariance of the electromagnetic field. We demonstrate that for a power-law type coupling, the current magnetic field strength of $\sim 10^{-9}$ G on 1 Mpc scale can be generated, if the backreaction effects and strong coupling problem are not taken into consideration.Comment: 4 pages, no figure, to be published in the Proceedings of the "12th Asia Pacific Physics Conference.

Inverse-Chirp Imprint of Gravitational Wave Signals in Scalar Tensor Theory

The scalar tensor theory contains a coupling function connecting the quantities in the Jordan and Einstein frames, which is constrained to guarantee a transformation rule between frames. We simulate the supernovae core collapse with different choices of coupling functions defined over the viable region of the parameter space and find that a generic inverse-chirp feature of the gravitational waves in the scalar tensor scenario.Comment: 13 pages, 4 figures, revised version accepted by EPJ

Peak Effect in Superconductors: Melting of Larkin Domains

Motivated by the recent observations of the peak effect in high-$T_c$ YBCO superconductors, we reexamine the origin of this unusual phenomenon. We show that the mechanism based on the $k$-dependence (nonlocality) of the vortex-lattice tilt modulus $C_{44}({\bf k})$ cannot account for the essential feature of the peak effect. We propose a scenario in which the peak effect is related to the melting of Larkin domains. In our model, the rise of critical current with increasing temperature is a result of a crossover from the Larkin pinning length to the length scale set by thermally excited free dislocations.Comment: 13 pages, 2 figures, REVTE

An Analysis of Witold Lutoslawski\u27s Variations on a Theme by Paganini for Two Pianos and an Original Composition Concerto for Two Pianos and Orchestra .

The dissertation is divided into two parts. Part I is an analysis of Witold Lutoslawski\u27s Variations on a Theme by Paganini for Two Pianos. This consists of a detailed analysis preceded by a brief introductory discussion of Witold Lutoslawski\u27s life and musical background. The composer has followed Paganini\u27s model faithfully as far as the basic thematic material is concerned. However, his addition of supporting harmonies, imitative and free countermelodies, and rhythmical accompaniments make this setting an original composition. This analysis focuses on harmony, dynamics, counterpoint, rhythm, form and general texture of the piece. The main issues to be discussed are Lutoslawski\u27s manipulation of the original subject matter, his development and usage of the above mentioned techniques. In harmony, the usage of polytonality, quartal and whole-tone harmony, tritone and third relationships are discussed. Graphic analyses illustrate the way dynamics shape the entire piece. Although Paganini\u27s theme was written for solo violin, Lutoslawski makes his version extremely contrapuntal by incorporating canon (both strict and inversion) between and within piano parts. Rhythmically, Lutoslawski follows the original version, but introduces some syncopations and off beat accents. Tempo, dynamic markings, texture and density make the piece seem to fall into three parts. The second part of this dissertation is an original composition, Concerto for Two Pianos and Orchestra. This three movement work is approximately twenty-five minutes in length. The tempos of the movements are fast-slow-fast. The entire piece includes quotations of Taiwanese folk tunes. The first movement\u27s tempo scheme is a palindrome: (A) \sb\bullet\!\!\sp\vert=69, (B) \sb\bullet\!\!\sp\vert=144, (C) \sb\bullet\!\!\sp\vert=100, (D) \sb\bullet\!\!\sp\vert=69, (C$\prime$) \sb\bullet\!\!\sp\vert=100, (B$\prime$) \sb\bullet\!\!\sp\vert=144, and (A$\prime$) \sb\bullet\!\!\sp\vert=69. It has also elements of a Sonata form regarding thematic materials. A is the introduction, B includes two contrasting themes, C and D are developmental, and B$\prime$-A$\prime$ is the recapitulation. The second movement is through composed. It employs quotations in a free manner. Movement three is a set of variations using a folk tune as the theme. In addition to the two solo pianos, the orchestral instrumentation includes the following: winds (2222), brass (2221), one timpanist, two percussionists, and strings (minimum 88642)