Reflection positive formulation of chiral gauge theories on a lattice

Gauge invariant chiral theories satisfying the reflection positivity is constructed on a lattice. This requires the introduction of "half gauge fields" defined some time ago by Brydges, Fr\"{o}hlich, and Seiler \cite{BFS}. A two-dimensional model is considered in some detail.Comment: 9 page

On behaviour of critical lines near ferrimagnetic phase in Higgs-Yukawa systems

We calculate within a mean-field approximation the slopes of the critical lines near the point of appearing the ferrimagnetic phase for the U(1) systems in the weak coupling regime. It is demonstrated that the slope of one of the critical line is continuous, while change of the slope of the other depends strongly on the number of the fermion flavours. We also find that in the ferrimagnetic phase near such a point the magnetization and the staggered magnetization align orthogonally to each other.Comment: 8 pages, latex, 1 figure; postscript file with the figure is appende

On a mean field approximation for Higgs-Yukawa systems

We discuss the phase structure of a lattice Higgs-Yukawa system in the variational mean field approximation with contributions of fermionic determinant being calculated in a ladder approximation. In particular, we demonstrate that in this approximation the ferrimagnetic phase in the $Z_2$ model with naive fermions can appear as an artifact of a finite lattice and that the phase diagram for this model on infinite lattice changes qualitatively at space-time dimension $D = 4$ compared with those at $D > 4$.Comment: 11 pages, 5 PostScript figures ( included ), harvmac and epsf, KYUSHU-HET-7. ( All is the same as the original one except that the EPSF macro is used for figures. Some PostScript errors in figures are removed.

A link between transcription fidelity and pausing in vivo

Pausing by RNA polymerase is a major mechanism that regulates transcription elongation but can cause conflicts with fellow RNA polymerases and other cellular machineries. Here, we summarize our recent finding that misincorporation could be a major source of transcription pausing in vivo, and discuss the role of misincorporation-induced pausing

The fermion determinant and the chiral gauge theory on a lattice

Considering as an example a simple lattice ansatz for the chiral fermion determinant, we demonstrate that even very mild violation of gauge invariance by the determinant at finite lattice spacing leads to the need for another scale in the full gauge theory. This new scale is much grater than the lattice spacing and is associated with the gauge variables.Comment: Talk presented at LATTICE96(chiral gauge), 3 pages, no figures, espcrc2. References to works of other authors are correcte

Misincorporation by RNA polymerase is a major source of transcription pausingin vivo

The transcription error rate estimated from mistakes in end product RNAs is 10−3–10−5. We analyzed the fidelity of nascent RNAs from all actively transcribing elongation complexes (ECs) in Escherichia coli and Saccharomyces cerevisiae and found that 1–3% of all ECs in wild-type cells, and 5–7% of all ECs in cells lacking proofreading factors are, in fact, misincorporated complexes. With the exception of a number of sequence-dependent hotspots, most misincorporations are distributed relatively randomly. Misincorporation at hotspots does not appear to be stimulated by pausing. Since misincorporation leads to a strong pause of transcription due to backtracking, our findings indicate that misincorporation could be a major source of transcriptional pausing and lead to conflicts with other RNA polymerases and replication in bacteria and eukaryotes. This observation implies that physical resolution of misincorporated complexes may be the main function of the proofreading factors Gre and TFIIS. Although misincorporation mechanisms between bacteria and eukaryotes appear to be conserved, the results suggest the existence of a bacteria-specific mechanism(s) for reducing misincorporation in protein-coding regions. The links between transcription fidelity, human disease, and phenotypic variability in genetically-identical cells can be explained by the accumulation of misincorporated complexes, rather than mistakes in mature RNA

Lattice fermions with gauge noninvariant measure

We define Weyl fermions on a finite lattice in such a way that in the path integral the action is gauge invariant but the functional measure is not. Two variants of such a formulation are tested in perturbative calculation of the fermion determinant in chiral Schwinger model. We find that one of these variants ensures restoring the gauge invariance of the nonanomalous part of the determinant in the continuum limit. A `perfect' perturbative regularization of the chiral fermions is briefly discussed.Comment: footnotes 2, 7 are extended, two references are adde

Better Actions

We explain why compact U(1) confines and how to fix it. We show that plaquettes of negative trace carry most of the confinement signal in compact SU(2). We show how to perform noncompact gauge-invariant simulations without auxiliary fields. We suggest a way to simulate fermions without doublers.Comment: Talk presented at LATTICE96(algorithms), 4 pages, Latex, espcrc2, picte