19,028 research outputs found
REINVESTIGATION OF THE REACTION OF [ETA-5-C5ME5(CO)2MO]2-(MO=MO) WITH PHOSPHORUS LIGANDS - FORMATION OF (C5ME5)2MO2(CO)3PR3-(MO=MO=) (PR3=P(OME)3 - PHP(OCH2CH2)2NH) AND C5ME5(CO)2[P(OME)3]ME, AND THE CRYSTAL-STRUCTURE OF (C5ME5)2MO2(CO)3[PHP(OCH2CH2)2NHI
Three-Loop Mixing of Dipole Operators
We calculate the complete three-loop O(alpha_s^3) anomalous dimension matrix
for the dimension-five dipole operators that arise in the Standard Model after
integrating out the top quark and the heavy electroweak bosons. Our computation
completes the three-loop anomalous dimension matrix of operators that govern
low-energy |Delta F| = 1 flavor-changing processes, and represents an important
ingredient of the next-to-next-to-leading order QCD analysis of the Bbar -> X_s
gamma decay.Comment: 4 pages, 1 figure; journal version, text below Eq. (7) correcte
Electron Self Energy for Higher Excited S Levels
A nonperturbative numerical evaluation of the one-photon electron self energy
for the 3S and 4S states with charge numbers Z=1 to 5 is described. The
numerical results are in agreement with known terms in the expansion of the
self energy in powers of Zalpha.Comment: 3 pages, RevTeX, to appear in Phys. Rev.
Phonon-dressed Mollow triplet in the regime of cavity-QED
We study the resonance fluorescence spectra of a driven quantum dot placed
inside a high semiconductor cavity and interacting with an acoustic phonon
bath. The dynamics is calculated using a time-convolutionless master equation
obtained in the polaron frame. We demonstrate pronounced spectral broadening of
the Mollow sidebands through cavity-emission which, for small cavity-coupling
rates, increases quadratically with the Rabi frequency. However, for larger
cavity coupling rates, this broadening dependence is found to be more complex.
This field-dependent Mollow triplet broadening is primarily a consequence of
the triplet peaks sampling different parts of the asymmetric phonon bath, and
agrees directly with recent experiments with semiconductor micropillars. The
influence from the detuned cavity photon bath and multi-photon effects is shown
to play a qualitatively important role on the fluorescence spectra.Comment: 4 pages, 4 figure
Open Space – a collaborative process for facilitating Tourism IT partnerships
The success of IT projects depends on the success of the partnerships on which they are based. However past research by the author has identified a significant rate of failure in these partnerships, predominantly due to an overly technical mindset, leading to the question: “how do we ensure that, as technological solutions are implemented within tourism, due consideration is given to human-centred issues?” The tourism partnership literature is explored for additional insights revealing that issues connected with power, participation and normative positions play a major role. The method, Open Space, is investigated for its ability to engage stakeholders in free and open debate. This paper reports on a one-day Open Space event sponsored by two major intermediaries in the UK travel industry who wanted to consult their business partners. Both the running of the event and its results reveal how Open Space has the potential to address some of the weaknesses associated with tourism partnerships
Static polarizability of two-dimensional hole gases
We have calculated the density-density (Lindhard) response function of a
homogeneous two-dimensional (2D) hole gas in the static (omega=0) limit. The
bulk valence-band structure comprising heavy-hole (HH) and light-hole (LH)
states is modeled using Luttinger's kdotp approach within the axial
approximation. We elucidate how, in contrast to the case of conduction
electrons, the Lindhard function of 2D holes exhibits unique features
associated with (i) the confinement-induced HH-LH energy splitting and (ii) the
HH-LH mixing arising from the charge carriers' in-plane motion. Implications
for the dielectric response and related physical observables are discussed.Comment: 11 pages, 3 figures, IOP latex style, v2: minor changes, to appear in
NJ
Real-time dynamics in spin-1/2 chains with adaptive time-dependent DMRG
We investigate the influence of different interaction strengths and
dimerizations on the magnetization transport in antiferromagnetic spin-1/2
XXZ-chains. We focus on the real-time evolution of the inhomogeneous initial
state with all spins pointing up along the z axis in the left half and down in
the right half of the chain, using the adaptive time-dependent density-matrix
renormalization group (adaptive t-DMRG). We find on time-scales accessible to
us ballistic magnetization transport for small Sz-Sz-interaction and arbitrary
dimerization, but almost no transport for stronger Sz-Sz-interaction, with a
sharp crossover at Jz=1. At Jz=1 results indicate superdiffusive transport.
Additionally, we perform a detailed analysis of the error made by the adaptive
time-dependent DMRG using the fact that the evolution in the XX-model is known
exactly. We find that the error at small times is dominated by the error made
by the Trotter decomposition, whereas for longer times the DMRG truncation
error becomes the most important, with a very sharp crossover at some "runaway"
time.Comment: 13 pages, 20 figure
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