16,182 research outputs found
Contemplating workplace change: evolving individual thought processes and emergent story lines
Drawing on topical life histories of physicians in a particularly volatile public health
sector environment, we build theory around the contemplation of workplace change.
Overall, our study provides evidence as to why single or multiple independent factors,
such as pay or job structure, may fail to predict or explain individual decisions to stay
in or change workplaces. Instead, the contemplation process we argue is a complex,
evolutionary, and context-dependent one that requires individualized interventions.
Our findings reveal the prevalence of episodic context-self fit assessments prompted
by triggering stimuli, two mechanisms by which thought processes evolved
(reinforcement and recalibration), and four characteristic story lines that explain
why the thought processes manifested as they did (exploring opportunities, solving
problems, reconciling incongruence, and escaping situations). Based on our findings,
we encourage practitioners to regularly engage in story-listening and dialogic
conversations to better understand, and potentially affect the evolving socially
constructed realities of staff members
Thermal evolution of the Schwinger model with Matrix Product Operators
We demonstrate the suitability of tensor network techniques for describing
the thermal evolution of lattice gauge theories. As a benchmark case, we have
studied the temperature dependence of the chiral condensate in the Schwinger
model, using matrix product operators to approximate the thermal equilibrium
states for finite system sizes with non-zero lattice spacings. We show how
these techniques allow for reliable extrapolations in bond dimension, step
width, system size and lattice spacing, and for a systematic estimation and
control of all error sources involved in the calculation. The reached values of
the lattice spacing are small enough to capture the most challenging region of
high temperatures and the final results are consistent with the analytical
prediction by Sachs and Wipf over a broad temperature range.Comment: 6 pages, 11 figure
The lowest-lying baryon masses in covariant SU(3)-flavor chiral perturbation theory
We present an analysis of the baryon-octet and -decuplet masses using
covariant SU(3)-flavor chiral perturbation theory up to next-to-leading order.
Besides the description of the physical masses we address the problem of the
lattice QCD extrapolation. Using the PACS-CS collaboration data we show that a
good description of the lattice points can be achieved at next-to-leading order
with the covariant loop amplitudes and phenomenologically determined values for
the meson-baryon couplings. Moreover, the extrapolation to the physical point
up to this order is found to be better than the linear one given at
leading-order by the Gell-Mann-Okubo approach. The importance that a reliable
combination of lattice QCD and chiral perturbation theory may have for hadron
phenomenology is emphasized with the prediction of the pion-baryon and
strange-baryon sigma terms.Comment: Typos in formulas correcte
On the efficient numerical solution of lattice systems with low-order couplings
We apply the Quasi Monte Carlo (QMC) and recursive numerical integration
methods to evaluate the Euclidean, discretized time path-integral for the
quantum mechanical anharmonic oscillator and a topological quantum mechanical
rotor model. For the anharmonic oscillator both methods outperform standard
Markov Chain Monte Carlo methods and show a significantly improved error
scaling. For the quantum mechanical rotor we could, however, not find a
successful way employing QMC. On the other hand, the recursive numerical
integration method works extremely well for this model and shows an at least
exponentially fast error scaling
Complexity and Inapproximability Results for Parallel Task Scheduling and Strip Packing
We study the Parallel Task Scheduling problem with a
constant number of machines. This problem is known to be strongly NP-complete
for each , while it is solvable in pseudo-polynomial time for each . We give a positive answer to the long-standing open question whether
this problem is strongly -complete for . As a second result, we
improve the lower bound of for approximating pseudo-polynomial
Strip Packing to . Since the best known approximation algorithm
for this problem has a ratio of , this result
narrows the gap between approximation ratio and inapproximability result by a
significant step. Both results are proven by a reduction from the strongly
-complete problem 3-Partition
Structure prediction based on ab initio simulated annealing for boron nitride
Possible crystalline modifications of chemical compounds at low temperatures
correspond to local minima of the energy landscape. Determining these minima
via simulated annealing is one method for the prediction of crystal structures,
where the number of atoms per unit cell is the only information used. It is
demonstrated that this method can be applied to covalent systems, at the
example of boron nitride, using ab initio energies in all stages of the
optimization, i.e. both during the global search and the subsequent local
optimization. Ten low lying structure candidates are presented, including both
layered structures and 3d-network structures such as the wurtzite and zinc
blende types, as well as a structure corresponding to the beta-BeO type
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