6,223 research outputs found
Gauge invariant effective action for the Polyakov line in the SU(N) Yang--Mills theory at high temperatures
We integrate out fast varying quantum fluctuations around static A_4 and A_i
fields for the SU(N) gauge group. By assuming that the gluon fields are slowly
varying but allowing for an arbitrary amplitude of A_4 we obtain two variants
of the effective high-temperature theory for the Polyakov line. One is the
effective action for the gauge-invariant eigenvalues of the Polyakov line, and
it is explicitly Z(N) symmetric. The other is the effective action for the
Polyakov line itself as an element of the SU(N). In this case the theory
necessarily includes the spatial components A_i to ensure its gauge invariance
under spatial gauge transformations. We derive the 1-loop effective action in
the `electric' and `magnetic' sectors, summing up all powers of A_4.Comment: RevTex4, 2 figure
‘You couldn’t finish the job without breaking the rules’: common sense safety on a large construction project
Electron capture to continuum in collisions of bare projectiles with Ne targets
Abstract. We have investigated the cusp resulting from electron capture to the continuum of 1.25-5 MeV m u- ' fully stripped hydrogen and oxygen as a function of the collision energy and the detector angular resolution B o. It is revealed that the characteristic cusp shape parameters depend strongly on the experimental resolution. Our experimental data are "pared with the second-order Born theory and the impulse approximation. Both theories mnhrm the 8, dependence of the shape parameters and gjve a reasonable descrip-lion of the cusp asymmetry. However, theory tends to overestimate the absolute cross sections, in particular in the case of oxygen. 1
Electron-spectroscopic investigation of metal-insulator transition in Sr2Ru1-xTixO4 (x=0.0-0.6)
We investigate the nature and origin of the metal-insulator transition in
Sr2Ru1-xTixO4 as a function of increasing Ti content (x). Employing detailed
core, valence, and conduction band studies with x-ray and ultraviolet
photoelectron spectroscopies along with Bremsstrahlung isochromat spectroscopy,
it is shown that a hard gap opens up for Ti content greater than equal to 0.2,
while compositions with x<0.2 exhibit finite intensity at the Fermi energy.
This establishes that the metal-insulator transition in this homovalent
substituted series of compounds is driven by Coulomb interaction leading to the
formation of a Mott gap, in contrast to transitions driven by disorder effects
or band flling.Comment: Accepted for publication in Phys. Rev.
The effect of pension accounting on corporate pension asset allocation
We examine the impact of new pension disclosures and subsequent full pension recognition under FRS 17 and IAS 19 in the United Kingdom and SFAS 158 in the United States on pension asset allocation. These standards require recognition of net pension surplus/deficit on the balance sheet and actuarial gains/losses in other comprehensive income. Therefore, these standards introduce volatility into comprehensive income and balance sheets. We identify a disclosure period during which UK companies disclosed all the required data under FRS 17 in the notes without recognition. We also identify a full recognition period starting 1 year before until 1 year after the adoption of FRS 17/IAS 19 (UK) and SFAS 158 (US). We predict and find that UK companies, on average, shifted pension assets from equity to debt securities during both the disclosure and the full recognition periods. We also find that while before the adoption of SFAS 158 US companies maintained a stable allocation to equities and bonds, these companies, on average, shifted funds from equities to bonds around the adoption of SFAS 158. Cross-sectional analysis shows that the shift away from equities is related to changes in funding levels, shorter investment horizons, increased financial leverage, and the expected impact of the new standards on shareholders' equity. © 2009 Springer Science+Business Media, LLC.postprin
Universality in the Crossover between Edge Channel and Bulk Transport in the Quantum Hall Regime
We present a new theoretical approach for the integer quantum Hall effect,
which is able to describe the inter-plateau transitions as well as the
transition to the Hall insulator. We find two regimes (metallic and insulator
like) of the top Landau level, in which the dissipative bulk current appears in
different directions. The regimes are separated by a temperature invariant
point.Comment: 4 page, 2 eps figures included, submitte
Mortality and immortality
It has been known for centuries that the rich and famous have longer lives than the poor and ordinary. Causality, however, remains trenchantly debated. The ideal experiment would be one in which status and money could somehow be dropped upon a sub-sample of individuals while those in a control group received neither. This paper attempts to formulate a test in that spirit. It collects 19th-century birth data on science Nobel Prize winners and nominees. Using a variety of corrections for potential biases, the paper concludes that winning the Nobel Prize, rather than merely being nominated, is associated with between 1 and 2 years of extra longevity. Greater wealth, as measured by the real value of the Prize, does not seem to affect lifespan
Time-dependent Hamiltonian estimation for Doppler velocimetry of trapped ions
The time evolution of a closed quantum system is connected to its Hamiltonian
through Schroedinger's equation. The ability to estimate the Hamiltonian is
critical to our understanding of quantum systems, and allows optimization of
control. Though spectroscopic methods allow time-independent Hamiltonians to be
recovered, for time-dependent Hamiltonians this task is more challenging. Here,
using a single trapped ion, we experimentally demonstrate a method for
estimating a time-dependent Hamiltonian of a single qubit. The method involves
measuring the time evolution of the qubit in a fixed basis as a function of a
time-independent offset term added to the Hamiltonian. In our system the
initially unknown Hamiltonian arises from transporting an ion through a static,
near-resonant laser beam. Hamiltonian estimation allows us to estimate the
spatial dependence of the laser beam intensity and the ion's velocity as a
function of time. This work is of direct value in optimizing transport
operations and transport-based gates in scalable trapped ion quantum
information processing, while the estimation technique is general enough that
it can be applied to other quantum systems, aiding the pursuit of high
operational fidelities in quantum control.Comment: 10 pages, 8 figure
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