BRST cohomology and Hodge decomposition theorem in Abelian gauge theory

We discuss the Becchi-Rouet-Stora-Tyutin (BRST) cohomology and Hodge decomposition theorem for the two dimensional free U(1) gauge theory. In addition to the usual BRST charge, we derive a local, conserved and nilpotent co(dual)-BRST charge under which the gauge-fixing term remains invariant. We express the Hodge decomposition theorem in terms of these charges and the Laplacian operator. We take a single photon state in the quantum Hilbert space and demonstrate the notion of gauge invariance, no-(anti)ghost theorem, transversality of photon and establish the topological nature of this theory by exploiting the concepts of BRST cohomology and Hodge decomposition theorem. In fact, the topological nature of this theory is encoded in the vanishing of the Laplacian operator when equations of motion are exploited. On the two dimensional compact manifold, we derive two sets of topological invariants with respect to the conserved and nilpotent BRST- and co-BRST charges and express the Lagrangian density of the theory as the sum of terms that are BRST- and co-BRST invariants. Mathematically, this theory captures together some of the key features of both Witten- and Schwarz type of topological field theories.Comment: 20 pages, LaTeX, no figures, Title and text have been changed, Journal reference is given, some references have been adde

Medical Information Management System (MIMS): An automated hospital information system

Flexible system of computer programs allows manipulation and retrieval of data related to patient care. System is written in version of FORTRAN developed for CDC-6600 computer

Topological aspects in non-Abelian gauge theory

We discuss the BRST cohomology and exhibit a connection between the Hodge decomposition theorem and the topological properties of a two dimensional free non-Abelian gauge theory having no interaction with matter fields. The topological nature of this theory is encoded in the vanishing of the Laplacian operator when equations of motion are exploited. We obtain two sets of topological invariants with respect to BRST and co-BRST charges on the two dimensional manifold and show that the Lagrangian density of the theory can be expressed as the sum of terms that are BRST- and co-BRST invariants.Comment: (1+11) pages, LaTeX, no figure

Line Ratios Reveal N2H+ Emission Originates Above the Midplane in TW Hydrae

Line ratios for different transitions of the same molecule have long been used as a probe of gas temperature. Here we use ALMA observations of the N2H+ J~=~1-0 and J~=~4-3 lines in the protoplanetary disk around TW Hya to derive the temperature at which these lines emit. We find an averaged temperature of 39~K with a one sigma uncertainty of 2~K for the radial range 0.8-2'', significantly warmer than the expected midplane temperature beyond 0.5'' in this disk. We conclude that the N2H+ emission in TW Hya is not emitting from near the midplane, but rather from higher in the disk, in a region likely bounded by processes such as photodissociation or chemical reprocessing of CO and N2 rather than freeze out.Comment: Accepted for publication in ApJ Letters, 5 pages, 1 figur

Slow-roll inflation with a Gauss-Bonnet correction

We consider slow-roll inflation for a single scalar field with an arbitrary potential and an arbitrary nonminimal coupling to the Gauss-Bonnet term. By introducing a combined hierarchy of Hubble and Gauss-Bonnet flow functions, we analytically derive the power spectra of scalar and tensor perturbations. The standard consistency relation between the tensor-to-scalar ratio and the spectral index of tensor perturbations is broken. We apply this formalism to a specific model with a monomial potential and an inverse monomial Gauss-Bonnet coupling and constrain it by the 7-year Wilkinson Microwave Anisotropy Probe data. The Gauss-Bonnet term with a positive (or negative) coupling may lead to a reduction (or enhancement) of the tensor-to-scalar ratio and hence may revive the quartic potential ruled out by recent cosmological data.Comment: 7 pages, 2 figures, RevTeX, references added, published versio

1RXSJ062518.2+733433: A bright, soft intermediate polar

We present the results of 50 hours time-resolved R-band photometry of the ROSAT all-sky survey source 1RXSJ062518.2+733433. The source was identified by Wei et al. (1999) as a cataclysmic variable. Our photometry, performed in 10 nights between February 11, 2003, and March 21, 2003, reveals two stable periodicities at 19.7874 and 283.118 min, which are identified as probable spin and orbital periods of the binary. We therefore classify 1RXSJ062518.2+733433 as an intermediate polar. Analysis of the RASS X-ray observations reveal a variability of 100% in the X-ray flux and a likely soft X-ray excess. The new IP thus joins the rare group of soft IPs with only four members so far.Comment: submitted to A&A, 5 pages, 6 figures of reduced qualit