Ginzburg - Landau equation from SU(2) gauge field theory

The dual superconductor picture of the QCD vacuum is thought to describe various aspects of the strong interaction including confinement. Ordinary superconductivity is described by the Ginzburg-Landau (GL) equation. In the present work we show that it is possible to arrive at a GL-like equation from pure SU(2) gauge theory. This is accomplished by using Abelian projection to split the SU(2) gauge fields into an Abelian subgroup and its coset. The two gauge field components of the coset part act as the effective, complex, scalar field of the GL equation. The Abelian part of the SU(2) gauge field is then analogous to the electromagnetic potential in the GL equation. An important aspect of the dual superconducting model is for the GL Lagrangian to have a spontaneous symmetry breaking potential, and the existence of Nielsen-Olesen flux tube solutions. Both of these require a tachyonic mass for the effective scalar field. Such a tachyonic mass term is obtained from the condensation of ghost fields.Comment: 7 pages, LATE

Searching for Effective Forces in Laboratory Insect Swarms

Collective animal behaviour is often modeled by systems of agents that interact via effective social forces, including short-range repulsion and long-range attraction. We search for evidence of such effective forces by studying laboratory swarms of the flying midge Chironomus riparius. Using multi-camera stereoimaging and particle-tracking techniques, we record three-dimensional trajectories for all the individuals in the swarm. Acceleration measurements show a clear short-range repulsion, which we confirm by considering the spatial statistics of the midges, but no conclusive long-range interactions. Measurements of the mean free path of the insects also suggest that individuals are on average very weakly coupled, but that they are also tightly bound to the swarm itself. Our results therefore suggest that some attractive interaction maintains cohesion of the swarms, but that this interaction is not as simple as an attraction to nearest neighbours

Confluent operator algebras and the closability property

Certain operator algebras A on a Hilbert space have the property that every densely defined linear transformation commuting with A is closable. Such algebras are said to have the closability property. They are important in the study of the transitive algebra problem. More precisely, if A is a two-transitive algebra with the closability property, then A is dense in the algebra of all bounded operators, in the weak operator topology. In this paper we focus on algebras generated by a completely nonunitary contraction, and produce several new classes of algebras with the closability property. We show that this property follows from a certain strict cyclicity property, and we give very detailed information on the class of completely nonunitary contractions satisfying this property, as well as a stronger property which we call confluence.Comment: Preliminary versio

MODELLING THE ELECTRON WITH COSSERAT ELASTICITY

Interactions between a finite number of bodies and the surrounding fluid, in a channel for instance, are investigated theoretically. In the planar model here the bodies or modelled grains are thin solid bodies free to move in a nearly parallel formation within a quasi-inviscid fluid. The investigation involves numerical and analytical studies and comparisons. The three main features that appear are a linear instability about a state of uniform motion, a clashing of the bodies (or of a body with a side wall) within a finite scaled time when nonlinear interaction takes effect, and a continuum-limit description of the body–fluid interaction holding for the case of many bodies

Microwave ISM Emission in the Green Bank Galactic Plane Survey: Evidence for Spinning Dust

We observe significant dust-correlated emission outside of H II regions in the Green Bank Galactic Plane Survey (-4 < b < 4 degrees) at 8.35 and 14.35 GHz. The rising spectral slope rules out synchrotron and free-free emission as majority constituents at 14 GHz, and the amplitude is at least 500 times higher than expected thermal dust emission. When combined with the Rhodes (2.326 GHz), and WMAP (23-94 GHz) data it is possible to fit dust-correlated emission at 2.3-94 GHz with only soft synchrotron, free-free, thermal dust, and an additional dust-correlated component similar to Draine & Lazarian spinning dust. The rising component generally dominates free-free and synchrotron for \nu >~ 14 GHz and is overwhelmed by thermal dust at \nu > 60 GHz. The current data fulfill most of the criteria laid out by Finkbeiner et al. (2002) for detection of spinning dust.Comment: ApJ in press. 26 pages, 11 figures, figures jpeg compressed to save spac

Casimir interactions in Ising strips with boundary fields: exact results

An exact statistical mechanical derivation is given of the critical Casimir forces for Ising strips with arbitrary surface fields applied to edges. Our results show that the strength as well as the sign of the force can be controled by varying the temperature or the fields. An interpretation of the results is given in terms of a linked cluster expansion. This suggests a systematic approach for deriving the critical Casimir force which can be used in more general models.Comment: 10 pages, 4 figure

Flight Test Methodology for NASA Advanced Inlet Liner on 737MAX-7 Test Bed (Quiet Technology Demonstrator 3)

This paper describes the acoustic flight test results of an advanced nacelle inlet acoustic liner concept designed by NASA Langley, in a campaign called Quiet Technology Demonstrator 3 (QTD3). NASA has been developing multiple acoustic liner concepts to benefit acoustics with multiple-degrees of freedom (MDOF) honeycomb cavities, and lower the excrescence drag. Acoustic and drag performance were assessed at a lab-scale, flow duct level in 2016. Limitations of the lab-scale rig left open-ended questions regarding the in-flight acoustic performance. This led to a joint project to acquire acoustic flyover data with this new liner technology built into full scale inlet hardware containing the NASA MDOF Low Drag Liner. Boeing saw an opportunity to collect the acoustic flyover data on the 737 MAX-7 between certification tests at no impact to the overall program schedule, and successfully executed within the allotted time. The flight test methodology and the test configurations are detailed and the acoustic analysis is summarized in this paper. After the tone and broadband deltas associated with the inlet hardware were separated and evaluated, the result was a significant decrease in cumulative EPNL (Effective Perceived Noise Level)