4,082 research outputs found
The Consequences of Being Different - Statistical Discrimination and the School-to-Work Transition
When information about the true abilities of job-seekers and applicants are hard to get, statistical discrimination by employers can be an efficient strategy in the hiring and wage setting process. But statistical discrimination can induce costs, if labor relations cannot be terminated in the short term and wages are fixed over a certain period. In this paper we use a unique longitudinal survey that follows the PISA 2000 students in their educational and work-life career. We test whether deviance in the PISA test scores from what one would have predicted based on observable characteristics, influences the probability to succeed in the transition from compulsory school into a firm-based apprenticeship and whether it can explain differences of the individual performances during training. Our results suggest that hard-to-get information plays a significant role in the transition, but not always in a symmetric manner.statistical discrimination, school-to-work transition, PISA
Force Statistics and Correlations in Dense Granular Packings
In dense, static, polydisperse granular media under isotropic pressure, the
probability density and the correlations of particle-wall contact forces are
studied. Furthermore, the probability density functions of the populations of
pressures measured with different sized circular pressure cells is examined.
The questions answered are: (i) What is the number of contacts that has to be
considered so that the measured pressure lies within a certain error margin
from its expectation value? (ii) What is the statistics of the pressure
probability density as function of the size of the pressure cell? Astonishing
non-random correlations between contact forces are evidenced, which range at
least 10 to 15 particle diameter. Finally, an experiment is proposed to tackle
and better understand this issue.Comment: 10 pages, 12 figure
Two-body recombination in a quantum mechanical lattice gas: Entropy generation and probing of short-range magnetic correlations
We study entropy generation in a one-dimensional (1D) model of bosons in an
optical lattice experiencing two-particle losses. Such heating is a major
impediment to observing exotic low temperature states, and "simulating"
condensed matter systems. Developing intuition through numerical simulations,
we present a simple empirical model for the entropy produced in this 1D
setting. We also explore the time evolution of one and two particle correlation
functions, showing that they are robust against two-particle loss. Because of
this robustness, induced two-body losses can be used as a probe of short range
magnetic correlations.Comment: 6 pages, 3 figures - v4, published versio
Domain wall dynamics in a two-component Bose-Mott insulator
We model the dynamics of two species of bosonic atoms trapped in an optical
lattice within the Mott regime by mapping the system onto a spin model. A field
gradient breaks the cloud into two domains. We study how the domain wall
evolves under adiabatic and diabatic changes of this gradient. We determine the
timescales for adiabaticity, and study how temperature evolves for slow ramps.
We show that after large, sudden changes of the field gradient, the system does
not equilibrate on typical experimental timescales. We find interesting spin
dynamics even when the initial temperature is large compared to the
super-exchange energy. We discuss the implication of our results for
experiments wishing to use such a two-component system for thermometry, or as
part of a cooling scheme.Comment: 6 pages, 5 figures Minor typographical errors corrected. Figure
labels changed. Added concluding statement
Stirring trapped atoms into fractional quantum Hall puddles
We theoretically explore the generation of few-body analogs of fractional
quantum Hall states. We consider an array of identical few-atom clusters
(n=2,3,4), each cluster trapped at the node of an optical lattice. By
temporally varying the amplitude and phase of the trapping lasers, one can
introduce a rotating deformation at each site. We analyze protocols for
coherently transferring ground state clusters into highly correlated states,
producing theoretical fidelities in excess of 99%.Comment: 4 pages, 3 figures (13 subfigures) -- v2: published versio
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