Competing orders in a magnetic field: spin and charge order in the cuprate superconductors

We describe two-dimensional quantum spin fluctuations in a superconducting Abrikosov flux lattice induced by a magnetic field applied to a doped Mott insulator. Complete numerical solutions of a self-consistent large N theory provide detailed information on the phase diagram and on the spatial structure of the dynamic spin spectrum. Our results apply to phases with and without long-range spin density wave order and to the magnetic quantum critical point separating these phases. We discuss the relationship of our results to a number of recent neutron scattering measurements on the cuprate superconductors in the presence of an applied field. We compute the pinning of static charge order by the vortex cores in the `spin gap' phase where the spin order remains dynamically fluctuating, and argue that these results apply to recent scanning tunnelling microscopy (STM) measurements. We show that with a single typical set of values for the coupling constants, our model describes the field dependence of the elastic neutron scattering intensities, the absence of satellite Bragg peaks associated with the vortex lattice in existing neutron scattering observations, and the spatial extent of charge order in STM observations. We mention implications of our theory for NMR experiments. We also present a theoretical discussion of more exotic states that can be built out of the spin and charge order parameters, including spin nematics and phases with `exciton fractionalization'.Comment: 36 pages, 33 figures; for a popular introduction, see http://onsager.physics.yale.edu/superflow.html; (v2) Added reference to new work of Chen and Ting; (v3) reorganized presentation for improved clarity, and added new appendix on microscopic origin; (v4) final published version with minor change

Biogenic Nitric Oxide Emission of Mountain Soils Sampled from Different Vertical Landscape Zones in the Changbai Mountains, Northeastern China

Nitric oxide (NO) is an important component in nitrogen biogeochemical cycling produced through biological processes of nitrification and denitrification in soils, but the production and the consumption processes of NO in temperate mountain soil are less understood. Through laboratory experiments focusing on NO biogenic emissions from six kinds of mountain soils sampled from different vertical landscape zones, that is, coniferous and broadleaf mixed forest (CBE), fir forest (FF), spruce forest (SF), Erman's birch forest (EBF), alpine tundra (AT), and volcanic ash (VA), in the Changbai Mountains, northeastern China, we found that the optimum water-filled pore space (WFPS) for NO production varies between 22.5% and 35% for a range of mountain soils. The optimum soil moisture for the maximum NO emission for a certain soil type, however, was constant and independent of soil temperature. The NO emission potential for forest soils was about 7-50-fold higher than tundra soil and volcanic ash, indicating that it is strongly influenced by nutrient contents in soils. On the basis of laboratory results and field monitoring data, the average NO fluxes from these mountain soils were estimated to be 0.14-29.56 ng N m(-2) s(-1) for an entire plant growth period. NO emissions mainly occur in wet season for CBF and FF, but in dry season for other soil types.Nitric oxide (NO) is an important component in nitrogen biogeochemical cycling produced through biological processes of nitrification and denitrification in soils, but the production and the consumption processes of NO in temperate mountain soil are less understood. Through laboratory experiments focusing on NO biogenic emissions from six kinds of mountain soils sampled from different vertical landscape zones, that is, coniferous and broadleaf mixed forest (CBE), fir forest (FF), spruce forest (SF), Erman's birch forest (EBF), alpine tundra (AT), and volcanic ash (VA), in the Changbai Mountains, northeastern China, we found that the optimum water-filled pore space (WFPS) for NO production varies between 22.5% and 35% for a range of mountain soils. The optimum soil moisture for the maximum NO emission for a certain soil type, however, was constant and independent of soil temperature. The NO emission potential for forest soils was about 7-50-fold higher than tundra soil and volcanic ash, indicating that it is strongly influenced by nutrient contents in soils. On the basis of laboratory results and field monitoring data, the average NO fluxes from these mountain soils were estimated to be 0.14-29.56 ng N m(-2) s(-1) for an entire plant growth period. NO emissions mainly occur in wet season for CBF and FF, but in dry season for other soil types

Biogeochemical Characterizations and Reclamation Strategies of Saline Sodic Soil in Northeastern China

Soil salinity and sodicity is considered one of the most import impediments to agricultural development in Northeast China The contents of TP and TK decrease with soil depth and high coefficients of variation were found in TOC AN and AP Mean EC in the 0-50 cm soil layers ranged from 0 61 to 0 89 dS m(-1) and the average soluble ion concentrations in the topsoil (0-10 cm) were approximately 11 38 mmol L-1 for Na+ 1 21 mmol L-1 for Ca2+ and 040 mmol L-1 for Mg2+ High SAR existed in the layers 10-50 cm indicating the studied soil was bearing low salinity in the top layer and high sodic layer in the subsurface The soil presented strong alkali reactions all through the profile with pH over 9 5 To improve and utilize saline sodic soil rationally several strategies were put forward based on long term field studies and demonstration works The results implied that ameliorating with sand applying farm yard manure regen erating salt tolerant grasses and leaching with groundwater and growing rice were effective measures for improving physical and chemical qualities of saline sodic soilSoil salinity and sodicity is considered one of the most import impediments to agricultural development in Northeast China The contents of TP and TK decrease with soil depth and high coefficients of variation were found in TOC AN and AP Mean EC in the 0-50 cm soil layers ranged from 0 61 to 0 89 dS m(-1) and the average soluble ion concentrations in the topsoil (0-10 cm) were approximately 11 38 mmol L-1 for Na+ 1 21 mmol L-1 for Ca2+ and 040 mmol L-1 for Mg2+ High SAR existed in the layers 10-50 cm indicating the studied soil was bearing low salinity in the top layer and high sodic layer in the subsurface The soil presented strong alkali reactions all through the profile with pH over 9 5 To improve and utilize saline sodic soil rationally several strategies were put forward based on long term field studies and demonstration works The results implied that ameliorating with sand applying farm yard manure regen erating salt tolerant grasses and leaching with groundwater and growing rice were effective measures for improving physical and chemical qualities of saline sodic soi

Reactive Trace Gas and Aerosol Fluxes (Chapter 9)

Quantifying the atmosphere-surface exchange of reactive trace gases and aerosols is extremely important for a full understanding of biogeochemical cycles and their implications for air quality and climate. However, turbulent fluxes of reactive gases such as ozone and volatile organic compounds (VOC) as well as aerosol particles are still difficult to measure. Chemical reactions contribute to changes in trace gas or aerosol concentrations, and production or loss processes have to be carefully separated from turbulent transport. Also, for many trace gas measurements and for size-resolved and chemically speciated aerosol measurements, instruments are limited with respect to time resolution, sensitivity, and accuracy, which restricts their application in micrometeorological techniques. Here, we present flux measurements of reactive trace gases and aerosols above tall vegetation. We focus on ozone deposition and its implications for the NO/NO2/O3 triad, biogenic emissions of volatile organic compounds and their subsequent oxidation reactions, and finally, turbulent aerosol fluxes in a spruce forest ecosystem