Demonstration of a 9 LP-mode transmission fiber with low DMD and loss

We experimentally demonstrate a 9 LP-mode (15 spatial modes) fiber with low DMD, confirmed by both time of flight and S2 measurements. Low loss (~0.2dB/km) is verified by OTDR measurement of the individual mode groups

Numerical Study of Gluon Propagator and Confinement Scenario in Minimal Coulomb Gauge

We present numerical results in SU(2) lattice gauge theory for the space-space and time-time components of the gluon propagator at equal time in the minimal Coulomb gauge. It is found that the equal-time would-be physical 3-dimensionally transverse gluon propagator $D^{tr}(\vec{k})$ vanishes at $\vec{k} = 0$ when extrapolated to infinite lattice volume, whereas the instantaneous color-Coulomb potential $D_{44}(\vec{k})$ is strongly enhanced at $\vec{k} = 0$. This has a natural interpretation in a confinement scenario in which the would-be physical gluons leave the physical spectrum while the long-range Coulomb force confines color. Gribov's formula $D^{tr}(\vec{k}) = (|\vec{k}|/2)[(\vec{k}^2)^2 + M^4]^{1/2}$ provides an excellent fit to our data for the 3-dimensionally transverse equal-time gluon propagator $D^{tr}(\vec{k})$ for relevant values of $\vec{k}$.Comment: 23 pages, 12 figures, TeX file. Minor modifications, incorporating referee's suggestion

Body Fixed Frame, Rigid Gauge Rotations and Large N Random Fields in QCD

The "body fixed frame" with respect to local gauge transformations is introduced. Rigid gauge "rotations" in QCD and their \Sch equation are studied for static and dynamic quarks. Possible choices of the rigid gauge field configuration corresponding to a nonvanishing static colormagnetic field in the "body fixed" frame are discussed. A gauge invariant variational equation is derived in this frame. For large number N of colors the rigid gauge field configuration is regarded as random with maximally random probability distribution under constraints on macroscopic--like quantities. For the uniform magnetic field the joint probability distribution of the field components is determined by maximizing the appropriate entropy under the area law constraint for the Wilson loop. In the quark sector the gauge invariance requires the rigid gauge field configuration to appear not only as a background but also as inducing an instantaneous quark-quark interaction. Both are random in the large N limit.Comment: 29 pages LATEX, Weizmann Institute preprint WIS-93/40/Apr -P

Bog bodies in context: developing a best practice approach

YesBog bodies are among the best-known archaeological finds worldwide. Much of the work on these often extremely well-preserved human remains has focused on forensics, whereas the environmental setting of the finds has been largely overlooked. This applies to both the ‘physical’ and ‘cultural’ landscape and constitutes a significant problem since the vast spatial and temporal scales over which the practice appeared demonstrate that contextual assessments are of the utmost importance for our explanatory frameworks. In this article we develop best practice guidelines for the contextual analysis of bog bodies after having assessed the current state of research and presented the results of three recent case studies including the well-known finds of Lindow Man in the United Kingdom, Bjældskovdal (Tollund Man and Elling Woman) in Denmark, and Yde Girl in the Netherlands. Three spatial and chronological scales are distinguished and linked to specific research questions and methods. This provides a basis for further discussion and a starting point for developing approaches to bog body finds and future discoveries, while facilitating and optimising the re-analysis of previous studies, making it possible to compare deposition sites across time and space.The Home Turf Project of Wageningen University and Research Centre, financed by the Dutch Organisation for Scientific Research (NWO Vidi Project, no. 276-60-003)

AR and MA representation of partial autocorrelation functions, with applications

We prove a representation of the partial autocorrelation function (PACF), or the Verblunsky coefficients, of a stationary process in terms of the AR and MA coefficients. We apply it to show the asymptotic behaviour of the PACF. We also propose a new definition of short and long memory in terms of the PACF.Comment: Published in Probability Theory and Related Field