BRST Invariant Higher Derivative Operators in 4D Quantum Gravity based on CFT

We continue the study of physical fields for the background free 4D quantum gravity based on the Riegert-Wess-Zumino action, developed in Phys. Rev. D {\bf 85} (2012) 024028. The background free model is formulated in terms of a certain conformal field theory on M^4 in which conformal symmetry arises as gauge symmetry, namely diffeomorphism invariance. In this paper, we construct the physical field operator corresponding to any integer power of Ricci scalar curvature in the context of the BRST quantization. We also discuss how to define the correlation function and its physical meanings.Comment: 22 pages, minor typo corrected, published versio

One-particle and collective electron spectra in hot and dense QED and their gauge dependence

The one-particle electron spectrum is found for hot and dense QED and its properties are investigated in comparison with the collective spectrum. It is shown that the one-particle spectrum (in any case its zero momentum limit) is gauge invariant, but the collective spectrum, being qualitatively different, is always gauge dependent. The exception is the case $m,\mu=0$ for which the collective spectrum long wavelength limit demonstrates the gauge invariance as well.Comment: 9 pages, latex, no figure

Quantum Hall Smectics, Sliding Symmetry and the Renormalization Group

In this paper we discuss the implication of the existence of a sliding symmetry, equivalent to the absence of a shear modulus, on the low-energy theory of the quantum hall smectic (QHS) state. We show, through renormalization group calculations, that such a symmetry causes the naive continuum approximation in the direction perpendicular to the stripes to break down through infrared divergent contributions originating from naively irrelevant operators. In particular, we show that the correct fixed point has the form of an array of sliding Luttinger liquids which is free from superficially "irrelevant operators". Similar considerations apply to all theories with sliding symmetries.Comment: 7 pages, 3 figure

Theoretical study of the accuracy limits for the optical resonance frequency measurements

The principal limits for the accuracy of the resonance frequency measurements set by the asymmetry of the natural resonance line shape are studied and applied to the recent accurate frequency measurements in the two-photon 1s-2s resonance and in the one-photon 1s-2p resonance in hydrogen atom. This limit for 1s-2s resonance is found to be $\sim 10^{-5}$ Hz compared to the accuracy achieved in experiment $\pm 46$ Hz. In case of deuterium atom the limit is essentially larger: $10^{-2}$ Hz. For 1s-2p resonance the accuracy limit is 0.17 MHz while the uncertainty of the recent frequency measurement is about 6 MHz.Comment: to be published in Physical Review Letter

3-point off-shell vertex in scalar QED in arbitrary gauge and dimension

We calculate the complete one-loop off-shell three-point scalar-photon vertex in arbitrary gauge and dimension for Scalar Quantum Electrodynamics. Explicit results are presented for the particular cases of dimensions 3 and 4 both for massive and massless scalars. We then propose non-perturbative forms of this vertex that coincide with the perturbative answer to order $e^2$.Comment: Uses axodra

Artificial electric field in Fermi Liquids

Based on the Keldysh formalism, we derive an effective Boltzmann equation for a quasi-particle associated with a particular Fermi surface in an interacting Fermi liquid. This provides a many-body derivation of Berry curvatures in electron dynamics with spin-orbit coupling, which has received much attention in recent years in non-interacting models. As is well-known, the Berry curvature in momentum space modifies naive band dynamics via an artificial magnetic field in momentum space. Our Fermi liquid formulation completes the reinvention of modified band dynamics by introducing in addition an "artificial electric field", related to Berry curvature in frequency and momentum space. We show explicitly how the artificial electric field affects the renormalization factor and transverse conductivity of interacting U(1) Fermi liquids with non-degenerate bands. Accordingly, we also propose a method of momentum resolved Berry's curvature detection in terms of angle resolved photoemission spectroscopy (ARPES)

Vacuum properties of a Non-Local Thirring-Like Model

We use path-integral methods to analyze the vacuum properties of a recently proposed extension of the Thirring model in which the interaction between fermionic currents is non-local. We calculate the exact ground state wave functional of the model for any bilocal potential, and also study its long-distance behavior. We show that the ground state wave functional has a general factored Jastrow form. We also find that it posess an interesting symmetry involving the interchange of density-density and current-current interactions.Comment: 25 pages, latex, no figure