Electron generation of leptons and hadrons with reciprocal alpha-quantized lifetimes and masses

Hadron elementary particle measurements have long revealed an alpha-dependence in the long-lived threshold-state lifetimes, together with an alpha-related mass structure, where alpha ~ 1/137 is the fine structure constant. A detailed lifetime analysis shows that of the 156 particles with well-determined lifetimes, the 120 shortest lifetimes have a continuum of values, but the 36 longer lifetimes occur in alpha-spaced groups which are sorted into s, c, b quark flavors. Guided by these lifetime results, we deduce an alpha-generated set of universal mass quanta, based on the electron ground state, which apply to both leptons and hadrons. A low-mass "threshold-state octet" of particles - muon, proton, tau, pion, eta, eta prime, kaon, phi meson - is reproduced to an average mass accuracy of 0.4%, with no adjustable parameters except a small hadronic binding energy. Without the lepton states, the hadron mass pattern is difficult to ascertain.Comment: 106 pages, 33 figures, invited review articl

Spin Ice, Fractionalization and Topological Order

The spin ice compounds {\dys} and {\holm} are highly unusual magnets which epitomize a set of concepts of great interest in modern condensed matter physics: their low-energy physics exhibits an emergent gauge field and their excitations are magnetic monopoles which arise from the fractionalization of the microscopic magnetic spin degrees of freedom. In this review, we provide an elementary introduction to these concepts and we survey the thermodynamics, statics and dynamics---in and out of equilibrium---of spin ice from these vantage points. Along the way, we touch on topics such as emergent Coulomb plasmas, observable "Dirac strings", and irrational charges. We close with the outlook for these unique materials.Comment: (15 pages, 9 figures) see http://www.annualreviews.org/doi/abs/10.1146/annurev-conmatphys-020911-125058 for the published versio

MgB2 radio-frequency superconducting quantum interference device prepared by atomic force microscope lithography

A new method of preparation of radio-frequency superconducting quantum interference devices on MgB2 thin films is presented. The variable-thickness bridge was prepared by a combination of optical lithography and of the scratching by an atomic force microscope. The critical current of the nanobridge was 0.35 uA at 4.2 K. Non-contact measurements of the current-phase characteristics and of the critical current vs. temperature have been investigated on our structures.Comment: RevTeX4. Accepted in Appl. Phys. Let