The Van der Waals interaction of the hydrogen molecule - an exact local energy density functional

We verify that the van der Waals interaction and hence all dispersion interactions for the hydrogen molecule given by: W"= -{A/R^6}-{B/R^8}-{C/R^10}- ..., in which R is the internuclear separation, are exactly soluble. The constants A=6.4990267..., B=124.3990835 ... and C=1135.2140398... (in Hartree units) first obtained approximately by Pauling and Beach (PB) [1] using a linear variational method, can be shown to be obtainable to any desired accuracy via our exact solution. In addition we shall show that a local energy density functional can be obtained, whose variational solution rederives the exact solution for this problem. This demonstrates explicitly that a static local density functional theory exists for this system. We conclude with remarks about generalising the method to other hydrogenic systems and also to helium.Comment: 11 pages, 13 figures and 28 reference

Coulomb Gauge QCD, Confinement, and the Constituent Representation

Quark confinement and the genesis of the constituent quark model are examined in nonperturbative QCD in Coulomb gauge. We employ a self-consistent method to construct a quasiparticle basis and to determine the quasiparticle interaction. The results agree remarkably well with lattice computations. They also illustrate the mechanism by which confinement and constituent quarks emerge, provide support for the Gribov-Zwanziger confinement scenario, clarify several perplexing issues in the constituent quark model, and permit the construction of an improved model of low energy QCD.Comment: 43 pages, 14 figures, revtex, uses psfig.st

Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation

The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas -- particle, nuclear and atomic is reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for EPJ

Rosamond et al. 2012 Figure 2

<p>Data used in Figure 2 of Rosamond et al. 2012, DOI 10.1038/NGEO1556</p

Changing nitrogen deposition with low δ15N−NH4+ and δ15N−NO3− values at the Experimental Lakes Area, northwestern Ontario, Canada

Ammonium deposition at the International Institute for Sustainable Development Experimental Lakes Area (IISD–ELA), in northwestern Ontario, Canada, has doubled in the last 45 years and thus is no longer among the low nitrogen (N) deposition sites in North America. This may be related to the concurrent intensification of Manitoba agriculture to the west and upwind of the ELA. Large increases in ammonium deposition at the ELA were important in driving the observed trend and increased the NH4 + to NO3 − ratio of input to aquatic and terrestrial systems. Stable isotope analyses of two years of bulk (wet and dry) atmospheric deposition revealed very large ranges in δ15N−NH4 + (22‰ range), δ15N−NO3 − (18‰), and δ18O–NO3 − (19‰). Few other δ15N−NH4 +, δ15N−NO3 −, and δ18O–NO3 − values have been published for Canadian precipitation. Increases in δ15N of NH4 + and NO3 − in July occurred with increases in total N deposition. The wide range and seasonal trends of δ15N and δ18O values in ELA precipitation mean that studies characterizing N inputs to watersheds and lakes require an ongoing and comprehensive annual sampling regime. Global trends of declining δ15N of N deposition evident in lake sediment records may be a result of increases in NH4 + deposition with lower δ15N−NH4 + values. Similarly, the relationship in Lake Superior between increasing NO3 − and lower δ15N−NO3 − values may be explained by increased atmospheric deposition of N with low δ15N values