Two-loop free energy of three-dimensional antiferromagnets in external magnetic and staggered fields

Using a model-independent low-energy effective field theory, we calculate the free energy of three-dimensional antiferromagnets in a combination of mutually perpendicular external magnetic and staggered fields at the next-to-next-to-leading, two-loop order. Renormalization is carried out analytically, and the renormalization group invariance of the result is checked explicitly. The free energy is thus expressed solely in terms of temperature, the external fields, and a set of low-energy coupling constants, to be determined by experiment or by matching to the microscopic model of a given concrete material.Comment: 19 page

2D-Oide effect

The Oide effect considers the synchrotron radiation in the final focusing quadrupole and it sets a lower limit on the vertical beam size at the Interaction Point, particularly relevant for high energy linear colliders. The theory of the Oide effect was derived considering only the radiation in the focusing plane of the magnet. This article addresses the theoretical calculation of the radiation effect on the beam size consider- ing both focusing and defocusing planes of the quadrupole, refered to as 2D-Oide. The CLIC 3 TeV final quadrupole (QD0) and beam parameters are used to compare the theoretical results from the Oide effect and the 2D-Oide effect with particle tracking in PLACET. The 2D-oide demonstrates to be important as it increases by 17% the contribution to the beam size. Further insight into the aberrations induced by the synchrotron radiation opens the possibility to partially correct the 2D-Oide effect with octupole mag

Towards a More Articulated and Relevant System of National Accounts

This article is part of the NEDA-PIDS Seminar-Workshop on the Philippine System of National Accounts. It reports what has been achieved after the last workshop held last November 1976. It also discusses the more pressing problems and issues relating to the balance of payment and government financial statistics.balance of payments, data and statistics, national account

Towards a More Articulated and Relevant System of National Accounts

This article is part of the NEDA-PIDS Seminar-Workshop on the Philippine System of National Accounts. It reports what has been achieved after the last workshop held last November 1976. It also discusses the more pressing problems and issues relating to the balance of payment and government financial statistics.balance of payments, data and statistics, national account

Current and current fluctuations in quantum shuttles

We review the properties of electron shuttles, i.e. nanoelectromechanical devices that transport electrons one-by-one by utilizing a combination of electronic and mechanical degrees of freedom. We focus on the extreme quantum limit, where the mechanical motion is quantized. We introduce the main theoretical tools needed for the analysis, e.g. generalized master equations and Wigner functions, and we outline the methods how the resulting large numerical problems can be handled. Illustrative results are given for current, noise, and full counting statistics for a number of model systems. Throughout the review we focus on the physics behind the various approximations, and some simple examples are given to illustrate the theoretical concepts. We also comment on the experimental situation.Comment: Minireview; technical level aimed at general audience, based on an invited talk at "Transport Phenomena in Micro and Nanodevices", October 17-21 Kona, Hawai

Light Nuclei in the Framework of the Symplectic No-core Shell Model

A symplectic no-core shell model (Sp-NCSM) is constructed with the goal of extending the {\it ab-initio} NCSM to include strongly deformed higher-oscillator-shell configurations and to reach heavier nuclei that cannot be studied currently because the spaces encountered are too large to handle, even with the best of modern-day computers. This goal is achieved by integrating two powerful concepts: the {\it ab-initio} NCSM with that of the $\mathrm{Sp}(3,\mathbb{R})\supset\mathrm{SU}(3)$ group-theoretical approach. The NCSM uses modern realistic nuclear interactions in model spaces that consists of many-body configurations up to a given number of $\hbar\Omega$ excitations together with modern high-performance parallel computing techniques. The symplectic theory extends this picture by recognizing that when deformed configurations dominate, which they often do, the model space can be better selected so less relevant low-lying $\hbar\Omega$ configurations yield to more relevant high-lying $\hbar\Omega$ configurations, ones that respect a near symplectic symmetry found in the Hamiltonian. Results from an application of the Sp-NCSM to light nuclei are compared with those for the NCSM and with experiment.Comment: 9 pages, 3 figures, Proceedings of the XXV International Workshop on Nuclear Theory, June 26-July 1, 2006, Rila Mountains, Bulgari