Particle Topology, Braids, and Braided Belts

Recent work suggests that topological features of certain quantum gravity theories can be interpreted as particles, matching the known fermions and bosons of the first generation in the Standard Model. This is achieved by identifying topological structures with elements of the framed Artin braid group on three strands, and demonstrating a correspondence between the invariants used to characterise these braids (a braid is a set of non-intersecting curves, that connect one set of $N$ points with another set of $N$ points), and quantities like electric charge, colour charge, and so on. In this paper we show how to manipulate a modified form of framed braids to yield an invariant standard form for sets of isomorphic braids, characterised by a vector of real numbers. This will serve as a basis for more complete discussions of quantum numbers in future work.Comment: 21 pages, 16 figure

Quantum gravity and the standard model

We show that a class of background independent models of quantum spacetime have local excitations that can be mapped to the first generation fermions of the standard model of particle physics. These states propagate coherently as they can be shown to be noiseless subsystems of the microscopic quantum dynamics. These are identified in terms of certain patterns of braiding of graphs, thus giving a quantum gravitational foundation for the topological preon model proposed by one of us. These results apply to a large class of theories in which the Hilbert space has a basis of states given by ribbon graphs embedded in a three-dimensional manifold up to diffeomorphisms, and the dynamics is given by local moves on the graphs, such as arise in the representation theory of quantum groups. For such models, matter appears to be already included in the microscopic kinematics and dynamics.Comment: 12 pages, 21 figures, improved presentation, results unchange

Design and construction of the MicroBooNE detector

This paper describes the design and construction of the MicroBooNE liquid argon time projection chamber and associated systems. MicroBooNE is the first phase of the Short Baseline Neutrino program, located at Fermilab, and will utilize the capabilities of liquid argon detectors to examine a rich assortment of physics topics. In this document details of design specifications, assembly procedures, and acceptance tests are reported

Gypsiferous groundwater and its desalination brine concentrate: Biomass, water use, and salt “mining” of three Southwestern USA native halophytes

In drought affected regions, alternative water sources and salt tolerant crops have become increasingly important. Although there is extensive documentation describing the response of halophytes to NaCl laboratory solutions, limited data exist on their responses to natural brackish groundwater (BGW) and desalination brine concentrate that could be dominated by ions other than Na and Cl. This study investigated the biomass, evapotranspiration (ET), water productivity (WP), and ion uptake responses of three southwestern USA native halophyte species, Atriplex canescens (Pursh) Nutt. (fourwing saltbush), A. lentiformis (Torr.) S. Watson (big saltbush), and Lepidium alyssoides A. Gray var. alyssoides (mesa pepperwort). Six-week-old seedlings were irrigated with a nonsaline control treatment solution [electrical conductivity (EC) of 0.6 dS m-1], CaSO4-dominant BGW (EC ≈ 4 dS m-1), CaSO4-dominant reverse osmosis (RO) concentrate (EC ≈ 8 dS m-1), and counterpart NaCl-dominant solutions (EC ≈ 4 or 8 dS m-1). After 6 wk, BGW and low NaCl solutions increased shoot biomass of . A. lentiformis by ≈ 20% but did not stimulate top growth of A. canescens or L. alyssoides. Increasing salinity had no effect on WP of L. alyssoides, but it increased WP of the Atriplex spp. The combined shoot Na and Cl concentrations reached 7% of dry wt. in L. alyssoides and 9–10% in the Atriplex spp. with no characteristic signs of leaf burn. Conversely, roots were the main sinks for Ca and S, combining for 6–7% of dry wt. and showing the potential to put the main brine solutes to beneficial use. Markedly similar patterns in growth and water use with the NaCl-only solutions and the CaSO4-dominant solutions suggests a primary role of total salinity in these salinity responses, which in turn supports the use of diverse BGW typesnot just NaCl for halophyte production