169 research outputs found

### Hydrodynamic theory of surface excitations of three-dimensional topological insulators

Edge excitations of a fractional quantum Hall system can be derived as
surface excitations of an incompressible quantum droplet using one dimensional
chiral bosonization. Here we show that an analogous approach can be developed
to characterize surface states of three-dimensional time reversal invariant
topological insulators. The key ingredient of our theory is the Luther's
multidimensional bosonization construction.Comment: 4 pages, published versio

### Unification of the Soluble Two-dimensional vector coupling models

The general theory of a massless fermion coupled to a massive vector meson in
two dimensions is formulated and solved to obtain the complete set of Green's
functions. Both vector and axial vector couplings are included. In addition to
the boson mass and the two coupling constants, a coefficient which denotes a
particular current definition is required for a unique specification of the
model.
The resulting four parameter theory and its solution are shown to reduce in
appropriate limits to all the known soluble models, including in particular the
Schwinger model and its axial vector variant.Comment: 10 page

### Soluble field theory with a massless gauge invariant limit

It is shown that there exists a soluble four parameter model in (1+1)
dimensions all of whose propagators can be determined in terms of the
corresponding known propagators of the vector coupling theory. Unlike the
latter case, however, the limit of zero bare mass is nonsingular and yields a
nontrivial theory with a rigorously unbroken gauge invariance.Comment: 7 pages, revtex, no figure

### Self-Interaction and Gauge Invariance

A simple unified closed form derivation of the non-linearities of the
Einstein, Yang-Mills and spinless (e.g., chiral) meson systems is given. For
the first two, the non-linearities are required by locality and consistency; in
all cases, they are determined by the conserved currents associated with the
initial (linear) gauge invariance of the first kind. Use of first-order
formalism leads uniformly to a simple cubic self-interaction.Comment: Missing last reference added. 9 pages, This article, the first paper
in Gen. Rel. Grav. [1 (1970) 9], is now somewhat inaccessible; the present
posting is the original version, with a few subsequent references included.
Updates update

### Quantum Electrodynamics of the Helium Atom

Using singlet S states of the helium atom as an example, I describe precise
calculation of energy levels in few-electron atoms. In particular, a complete
set of effective operators is derived which generates O(m*alpha^6) relativistic
and radiative corrections to the Schr"odinger energy. Average values of these
operators can be calculated using a variational Schr"odinger wave function.Comment: 23 pages, revte

### Supersymmetry and the Chiral Schwinger Model

We have constructed the N=1/2 supersymmetric general Abelian model with
asymmetric chiral couplings. This leads to a N=1/2 supersymmetrization of the
Schwinger model. We show that the supersymmetric general model is plagued with
problems of infrared divergence. Only the supersymmetric chiral Schwinger model
is free from such problems and is dynamically equivalent to the chiral
Schwinger model because of the peculiar structure of the N=1/2 multiplets.Comment: one 9 pages Latex file, one ps file with one figur

### The contribution of fermionic seesaws to the anomalous magnetic moment of leptons

We calculate the contribution to the anomalous magnetic moment of leptons in
the type-I and type-III seesaw models. We show that, even if the scale of the
new physics is pushed down to the electroweak scale, this contribution is not
large enough to explain the measured discrepancy of the muon anomalous magnetic
moment.Comment: 13 pages, uses axodraw.sty. References added, formulas corrected,
comments added, results and conclusions unchanged. Version to appear on Phys.
Lett.

### Reconsidered estimates of the 10th order QED contributions to the muon anomaly

The problem of estimating the 10th order QED corrections to the muon
anomalous magnetic moment is reconsidered. The incorporation of the recently
improved contributions to the $\alpha^4$ and $\alpha^5$- corrections to
$a_{\mu}$ within the renormalization-group inspired scheme-invariant approach
leads to the estimate $a_{\mu}^{(10)}\approx 643(\alpha/pi)^5$. It is in good
agreement with the estimate $a_{\mu}^{(10)}= 663(20) (\alpha/\pi)^5$, obtained
by Kinoshita and Nio from the numerical calculations of 2958 10-th order
diagrams, which are considered to be more important than the still uncalculated
6122 10th-order $m_{\mu}/m_e$-dependent vertex graphs, and 12672 5-loop
diagrams, responsible for the mass-independent constant contribution both to
$a_{\mu}$ and $a_e$. This confirms Kinoshita and Nio guess about dominance of
the 10-th order diagrams calculated by them. Comparisons with other estimates
of the $\alpha^5$- contributions to $a_{\mu}$, which exist in the literature,
are presented.Comment: 19 pages, LaTeX, some misprints in the text and literature corrected.
Results unchaged, to appear in Phys.Rev.

### Vector mesons in a relativistic point-form approach

We apply the point form of relativistic quantum mechanics to develop a
Poincare invariant coupled-channel formalism for two-particle systems
interacting via one-particle exchange. This approach takes the exchange
particle explicitly into account and leads to a generalized eigenvalue equation
for the Bakamjian-Thomas type mass operator of the system. The coupling of the
exchange particle is derived from quantum field theory. As an illustrative
example we consider vector mesons within the chiral constituent quark model in
which the hyperfine interaction between the confined quark-antiquark pair is
generated by Goldstone-boson exchange. We study the effect of retardation in
the Goldstone-boson exchange by comparing with the commonly used instantaneous
approximation. As a nice physical feature we find that the problem of a too
large $\rho$-$\omega$ splitting can nearly be avoided by taking the dynamics of
the exchange meson explicitly into account.Comment: 14 pages, 1 figur

### Particle Spectrum Created Through Bubble Nucleation

Using the multi-dimensional wave function formalism, we investigate the
quantum state of a scalar field inside a true vacuum bubble nucleated through
false vacuum decay in flat spacetime. We developed a formalism which allows us
a mode-by-mode analysis. To demonstrate its advantage, we describe in detail
the evolution of the quantum state during the tunneling process in terms of
individual mode functions and interpret the result in the language of particle
creation. The spectrum of the created particles is examined based on quantum
field theory in the Milne universe.Comment: 14 pages, revtex file, 4 uuencoded compressed postscript figures
appended at the en

- …