Solitons in a Baby-Skyrme model with invariance under area preserving diffeomorphisms

We study the properties of soliton solutions in an analog of the Skyrme model in 2+1 dimensions whose Lagrangian contains the Skyrme term and the mass term, but no usual kinetic term. The model admits a symmetry under area preserving diffeomorphisms. We solve the dynamical equations of motion analytically for the case of spinning isolated baryon type solitons. We take fully into account the induced deformation of the spinning Skyrmions and the consequent modification of its moment of inertia to give an analytical example of related numerical behaviour found by Piette et al.. We solve the equations of motion also for the case of an infinite, open string, and a closed annular string. In each case, the solitons are of finite extent, so called "compactons", being exactly the vacuum outside a compact region. We end with indications on the scattering of baby-Skyrmions, as well as some considerations as the properties of solitons on a curved space.Comment: 30 pages, 5 figures, revtex, major modifications, conclusions modifie

Advanced Control Technologies and Strategies Linking Demand Response and Energy Efficiency

This paper presents a preliminary framework to describe how advanced controls can support multiple modes of operations including both energy efficiency and demand response (DR). A general description of DR, its benefits, and nationwide status is outlined. The role of energy management and control systems for DR is described. Building systems such as HVAC and lighting that utilize control technologies and strategies for energy efficiency are mapped on to DR and demand shedding strategies are developed. Past research projects are presented to provide a context for the current projects. The economic case for implementing DR from a building owner perspective is also explored

Soliton-potential interaction in the nonlinear Klein-Gordon model

The interaction of solitons with external potentials in nonlinear Klein-Gordon field theory is investigated using an improved model. The presented model has been constructed with a better approximation for adding the potential to the Lagrangian through the metric of background space-time. The results of the model are compared with another model and the differences are discussed.Comment: 14 pages,8 figure

Chilled Water Thermal Storage System and Demand Response at the University of California at Merced

University of California at Merced is a unique campus that has benefited from intensive efforts to maximize energy efficiency, and has participated in a demand response program for the past two years. Campus demand response evaluations are often difficult because of the complexities introduced by central heating and cooling, non-coincident and diverse building loads, and existence of a single electrical meter for the entire campus. At the University of California at Merced, a two million gallon chilled water storage system is charged daily during off-peak price periods and used to flatten the load profile during peak demand periods, further complicating demand response scenarios. The goal of this research is to study demand response savings in the presence of storage systems in a campus setting. First, University of California at Merced is described and its participation in a demand response event during 2008 is detailed. Second, a set of demand response strategies were pre-programmed into the campus control system to enable semi-automated demand response during a 2009 event, which is also evaluated. Finally, demand savings results are applied to the utility’s DR incentives structure to calculate the financial savings under various DR programs and tariffs

The field theory of Skyrme lattices in quantum Hall ferromagnets

We report the application of the nonlinear $\sigma$ model to study the multi-skyrmion problem in the quantum Hall ferromagnet system. We show that the ground state of the system can be described by a ferromagnet triangular Skyrme lattice near $\nu=1$ where skyrmions are extremely dilute. We find a transition into antiferromagnet square lattice by increasing the skyrmion density and therefore $|\nu-1|$. We investigate the possibility that the square Skyrme lattice deforms to a single skyrmion with the same topological charge when the Zeeman energy is extremely smaller than the Coulomb energy. We explicitly show that the energy of a skyrmion with charge two is less than the energy of two skyrmions each with charge one when $g \leq g_c$. By taking the quantum fluctuations into account, we also argue the possibility of the existence of a non-zero temperature Kosterlitz-Thouless and a superconductor-insulator phase transition.Comment: 17 page

Collision-Induced Decay of Metastable Baby Skyrmions

Many extensions of the standard model predict heavy metastable particles which may be modeled as solitons (skyrmions of the Higgs field), relating their particle number to a winding number. Previous work has shown that the electroweak interactions admit processes in which these solitons decay, violating standard model baryon number. We motivate the hypothesis that baryon-number-violating decay is a generic outcome of collisions between these heavy particles. We do so by exploring a 2+1 dimensional theory which also possesses metastable skyrmions. We use relaxation techniques to determine the size, shape and energy of static solitons in their ground state. These solitons could decay by quantum mechanical tunneling. Classically, they are metastable: only a finite excitation energy is required to induce their decay. We attempt to induce soliton decay in a classical simulation by colliding pairs of solitons. We analyze the collision of solitons with varying inherent stabilities and varying incident velocities and orientations. Our results suggest that winding-number violating decay is a generic outcome of collisions. All that is required is sufficient (not necessarily very large) incident velocity; no fine-tuning of initial conditions is required.Comment: 24 pages, 7 figures, latex. Very small changes onl

Post‐discharge tobacco cessation rates among hospitalized US veterans with and without diabetes

Aims  Smoking is a major risk factor for cardiovascular complications among patients with diabetes. Hospitalization has been shown to enhance cessation rates. The purpose of this study was to compare 6‐month post‐hospitalization tobacco cessation rates among US veterans with and without diabetes. Methods  This was a longitudinal study among inpatient veterans who used tobacco in the past month ( n  = 496). Patients were recruited and surveyed from three Midwestern Department of Veterans Affairs hospitals during an acute‐care hospitalization. They were also asked to complete a follow‐up survey 6 months post‐discharge. Bivariate‐ and multivariable‐adjusted analyses were conducted to determine differences in tobacco cessation rates between patients with and without a diagnosis of diabetes. Results  The mean age of patients was 55.2 years and 62% were white. Twenty‐nine per cent had co‐morbid diabetes. A total of 18.8% of patients with diabetes reported tobacco cessation at 6 months compared with 10.9% of those without diabetes ( P  = 0.02). Cotinine‐verified cessation rates were 12.5 vs. 7.4% in the groups with and without diabetes, respectively ( P  = 0.07). Controlling for psychiatric co‐morbidities, depressive symptoms, age, self‐rated health and nicotine dependence, the multivariable‐adjusted logistic regression showed that patients with diabetes had three times higher odds of 6‐month cotinine‐verified tobacco cessation as compared with those without diabetes (odds ratio 3.17, P  = 0.005). Conclusions  Post‐hospitalization rates of smoking cessation are high among those with diabetes. Intensive tobacco cessation programmes may increase these cessation rates further.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92145/1/j.1464-5491.2012.03635.x.pd

Chern-Simons Solitons, Toda Theories and the Chiral Model

The two-dimensional self-dual Chern--Simons equations are equivalent to the conditions for static, zero-energy solutions of the $(2+1)$-dimensional gauged nonlinear Schr\"odinger equation with Chern--Simons matter-gauge dynamics. In this paper we classify all finite charge $SU(N)$ solutions by first transforming the self-dual Chern--Simons equations into the two-dimensional chiral model (or harmonic map) equations, and then using the Uhlenbeck--Wood classification of harmonic maps into the unitary groups. This construction also leads to a new relationship between the $SU(N)$ Toda and $SU(N)$ chiral model solutions