260 research outputs found
Controlling the dynamics of an open many-body quantum system with localized dissipation
We experimentally investigate the action of a localized dissipative potential
on a macroscopic matter wave, which we implement by shining an electron beam on
an atomic Bose-Einstein condensate (BEC). We measure the losses induced by the
dissipative potential as a function of the dissipation strength observing a
paradoxical behavior when the strength of the dissipation exceeds a critical
limit: for an increase of the dissipation rate the number of atoms lost from
the BEC becomes lower. We repeat the experiment for different parameters of the
electron beam and we compare our results with a simple theoretical model,
finding excellent agreement. By monitoring the dynamics induced by the
dissipative defect we identify the mechanisms which are responsible for the
observed paradoxical behavior. We finally demonstrate the link between our
dissipative dynamics and the measurement of the density distribution of the BEC
allowing for a generalized definition of the Zeno effect. Due to the high
degree of control on every parameter, our system is a promising candidate for
the engineering of fully governable open quantum systems
Spatio-temporal Fermionization of Strongly Interacting 1D Bosons
Building on the recent experimental achievements obtained with scanning
electron microscopy on ultracold atoms, we study one-dimensional Bose gases in
the crossover between the weakly (quasi-condensate) and the strongly
interacting (Tonks-Girardeau) regime. We measure the temporal two-particle
correlation function and compare it with calculations performed using the Time
Evolving Block Decimation algorithm. More pronounced antibunching is observed
when entering the more strongly interacting regime. Even though this mimics the
onset of a fermionic behavior, we highlight that the exact and simple duality
between 1D bosons and fermions does not hold when such dynamical response is
probed. The onset of fermionization is also reflected in the density
distribution, which we measure \emph{in situ} to extract the relevant
parameters and to identify the different regimes. Our results show agreement
between experiment and theory and give new insight into the dynamics of
strongly correlated many-body systems
Quantum transport in ultracold atoms
Ultracold atoms confined by engineered magnetic or optical potentials are
ideal systems for studying phenomena otherwise difficult to realize or probe in
the solid state because their atomic interaction strength, number of species,
density, and geometry can be independently controlled. This review focuses on
quantum transport phenomena in atomic gases that mirror and oftentimes either
better elucidate or show fundamental differences with those observed in
mesoscopic and nanoscopic systems. We discuss significant progress in
performing transport experiments in atomic gases, contrast similarities and
differences between transport in cold atoms and in condensed matter systems,
and survey inspiring theoretical predictions that are difficult to verify in
conventional setups. These results further demonstrate the versatility offered
by atomic systems in the study of nonequilibrium phenomena and their promise
for novel applications.Comment: 24 pages, 7 figures. A revie
Studying Children's Intrapersonal Emotion Regulation Strategies from the Process Model of Emotion Regulation
peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=vgnt2
The structure of PGC Morale Scale in American and Japanese aged: A further note
This study involves a further replication of cross-cultural comparison of the structure of the Philadelphia Geriatric Center Morale Scale (PGCMS). Using Japanese and American data sets, the present research replicates and extends the findings reported by Liang et al. (1987). In particular, the earlier findings that four PGCMS items behave differently in two cultures are replicated. The present study yields two additional observations. First, the invariance in the PGCMS can now be extended beyond the urban elderly residents studied by Liang et al. (1987) to the entire aged population in the U.S. and Japan. Second, this comparability is robust despite the elimination of correlated measurement errors from the earlier specifications and when several exogenous variables are controlled. Further, the impact of selected demographic variables on the PGCMS was evaluated. In addition, qualitative data from in-depth interviews provide further insights concerning the cultural differences in the expression of well-being.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42991/1/10823_2004_Article_BF00116576.pd
Effects of parental imprisonment on child antisocial behaviour and mental health: a systematic review
Parental imprisonment can cause many problems for the family left behind,
including difficulty organising childcare, loss of family income, trouble maintaining
contact with the imprisoned parent, stigma, and home, school and neighbourhood
moves. Children and parents can be distressed by the separation. Children may
respond by acting out or becoming withdrawn, anxious or depressed. We conducted
an exhaustive search for studies that examined children's antisocial behaviour and
mental health after parental imprisonment. We found 16 studies with appropriate
evidence. These studies all showed that children of prisoners are more likely than
other children to show antisocial and mental health problems. However, it was
unclear whether parental imprisonment actually caused these problems. They might
have been caused by other disadvantages in children's lives that existed before
parental imprisonment occurred. Children of prisoners are a vulnerable group. More
research is required to determine whether or not parental imprisonment causes an
increase in child antisocial behaviour and mental health problems
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