Lattice gauge theory with a fast highly parallel computer

Results for the temperature of the color deconfinement phase transition in pure SU(3) lattice gauge theory are described. These were obtained on a specially built 16-node, 256 Megaflop computer using the Metropolis algorithm. The architecture, performance, and expansion plans for this machine are also discussed. This work has been supported in part by the Department of Energy and the Intel Corporation.     

High-resolution calorimetric investigation of the existence of a nematic phase for the dodecylcyanobiphenyl liquid crystal

We have employed high-resolution calorimetric techniques in order to investigate the unresolved issue of the existence of a nematic phase for the liquid crystal dodecylcyanobiphenyl. Various heating and cooling runs were performed on dodecylcyanobiphenyl samples of different origin and their analysis did not reveal any signature of a nematic phase. The calorimetric results are presented in detail and they are additionally supported by optical polarising microscopy observations.     

Weak temporal ratchet effect by asymmetric modulation of a laser

Subjecting lasers to triangular modulations of the pump produces phenomena that drastically depend on the symmetry of the triangle. For instance, with slow up-rising triangles, a laser below threshold on average may deliver coherent pulses, while it does not deliver coherent pulses with fast up-rising triangles. This effect, which requires the presence of fluctuations in addition to the modulation, is reminiscent of the thermal ratchet with which a directed motion is extracted from a stochastic medium.     

Measurement of single electrons and implications for charm production in Au+Au collisions at square root[s(NN)] = 130 GeV

Transverse momentum spectra of electrons from Au+Au collisions at square root[s(NN)] = 130 GeV have been measured at midrapidity by the PHENIX experiment at the Relativistic Heavy Ion Collider. The spectra show an excess above the background from photon conversions and light hadron decays. The electron signal is consistent with that expected from semileptonic decays of charm. The yield of the electron signal dN(e)/dy for p(T) > 0.8 GeV/c is 0.025+/-0.004(stat)+/-0.010(syst) in central collisions, and the corresponding charm cross section is 380+/-60(stat)+/-200(syst) microb per binary nucleon-nucleon collision.     

Maximal functions associated with Fourier multipliers of Mikhlin-Hörmander type

We show that maximal operators formed by dilations of Mikhlin- Hörmander multipliers are typically not bounded on L^p(^d). We also give rather weak conditions in terms of the decay of such multipliers under which L^p boundedness of the maximal operators holds.Christ, Grafakos and Seeger were supported in part by NSF grants. Honzík was supported by 201/03/0931 Grant Agency of the Czech Republic     

Flavor symmetry breaking and scaling for improved staggered actions in quenched QCD

We present a study of the flavor symmetry breaking in the pion spectrum for the p4-improved fermion action. Three different variants of the p4 action – p4fat3, p4fat7, and p4fat7tad – are compared to the Asqtad and naive staggered actions. To study the pattern of symmetry breaking, we measure all 15 pion masses in the four-flavor staggered theory. The measurements are done on a quenched gauge background, generated using a one-loop improved Symanzik action with β=10/g²=7.40, 7.75, and 8.00, corresponding to lattice spacings of approximately a= 0.31 fm, 0.21 fm, and 0.14 fm. PACS 11.15.Ha; 11.30.Rd; 12.38.Aw; 12.38.-t; 12.38.Gc     

Waveguide-plasmon polaritons: strong coupling of photonic and electronic resonances in a metallic photonic crystal slab

Strong coupling between localized particle plasmons and optical waveguide modes leads to drastic modifications of the transmission of metallic nanowire arrays on dielectric waveguide substrates. The coupling results in the formation of a new quasiparticle, a waveguide-plasmon polariton, with a surprisingly large Rabi splitting of 250 meV. Our experimental results agree well with scattering-matrix calculations and a polariton-type model. The effect provides an efficient tool for photonic band gap engineering in metallodielectric photonic crystal slabs. We show evidence of a full one-dimensional photonic band gap in resonant plasmon-waveguide structures.     

Weights of links and plaquettes in a random lattice

In a random lattice, links and plaquettes have varying sizes and orientations. Therefore, they should enter the action function with different weights. A particularly attractive choice of these weights is presented; its consequences for $\text{spin}\text{-0,}\text{1}\text{2}\text{and}\text{1}$ fields on such a lattice are discussed.