760 research outputs found
Entanglement properties of degenerate four-wave mixing of matter-waves in a periodic potential
In a recent experiment Campbell et al. [Phys. Rev. Lett. 96, 020406 (2006)]
observed degenerate four-wave mixing of matter-waves in a one-dimensional
optical lattice, a process with potential for generating entanglement among
atoms. We analyse the essential quantum features of the experiment to show that
entanglement is created between the quadratures of the two scattered atomic
clouds and is a true many-body (rather than two-body) effect. We demonstrate a
significant violation of entanglement inequalities that is robust to a moderate
level of coherent seeding. The system is thus a promising candididate for
generating macroscopically entangled atomic samples.Comment: 4 pages, 3 figure
Squeezing and entangling nuclear spins in helium 3
We present a realistic model for transferring the squeezing or the
entanglement of optical field modes to the collective ground state nuclear spin
of He using metastability exchange collisions. We discuss in detail the
requirements for obtaining good quantum state transfer efficiency and study the
possibility to readout the nuclear spin state optically
Research poster: Losing the lake: Misconceptions regarding water resources and climate change
Research poste
Non-diffusive phase spreading of a Bose-Einstein condensate at finite temperature
We show that the phase of a condensate in a finite temperature gas spreads
linearly in time at long times rather than in a diffusive way. This result is
supported by classical field simulations, and analytical calculations which are
generalized to the quantum case under the assumption of quantum ergodicity in
the system. This super-diffusive behavior is intimately related to conservation
of energy during the free evolution of the system and to fluctuations of energy
in the prepared initial state.Comment: 16 pages, 7 figure
Detecting phonons and persistent currents in toroidal Bose-Einstein condensates by means of pattern formation
We theoretically investigate the dynamic properties of a Bose-Einstein
condensate in a toroidal trap. A periodic modulation of the transverse
confinement is shown to produce a density pattern due to parametric
amplification of phonon pairs. By imaging the density distribution after free
expansion one obtains i) a precise determination of the Bogoliubov spectrum and
ii) a sensitive detection of quantized circulation in the torus. The parametric
amplification is also sensitive to thermal and quantum fluctuations.Comment: 4 pages, 4 figures; new figures, revised version to appear as a Rapid
Communication in Physical Review
Bogoliubov dynamics of condensate collisions using the positive-P representation
We formulate the time-dependent Bogoliubov dynamics of colliding
Bose-Einstein condensates in terms of a positive-P representation of the
Bogoliubov field. We obtain stochastic evolution equations for the field which
converge to the full Bogoliubov description as the number of realisations
grows. The numerical effort grows linearly with the size of the computational
lattice. We benchmark the efficiency and accuracy of our description against
Wigner distribution and exact positive-P methods. We consider its regime of
applicability, and show that it is the most efficient method in the common
situation - when the total particle number in the system is insufficient for a
truncated Wigner treatment.Comment: 9 pages. 5 figure
Validation of the Internet Gaming Disorder Scale - Short-Form (IGDS9-SF) in an Italian-speaking sample
Background and aims: The inclusion of Internet Gaming Disorder (IGD) in Section III of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders has increased the interest of researchers in the development of new standardized psychometric tools for the assessment of such a disorder. To date, the nine-item Internet Gaming Disorder Scale - Short-Form (IGDS9-SF) has only been validated in English, Portuguese, and Slovenian languages. Therefore, the aim of this investigation was to examine the psychometric properties of the IGDS9-SF in an Italian-speaking sample. Methods: A total of 757 participants were recruited to the present study. Confirmatory factor analysis and multi-group analyses were applied to assess the construct validity. Reliability analyses comprised the average variance extracted, the standard error of measurement, and the factor determinacy coefficient. Convergent and criterion validities were established through the associations with other related constructs. The receiver operating characteristic curve analysis was used to determine an empirical cut-off point. Results: Findings confirmed the singlefactor structure of the instrument, its measurement invariance at the configural level, and the convergent and criterion validities. Satisfactory levels of reliability and a cut-off point of 21 were obtained. Discussion and conclusions: The present study provides validity evidence for the use of the Italian version of the IGDS9-SF and may foster research into gaming addiction in the Italian context
Real-World Engagement with Controversial Issues in History and Social Studies: Teaching for Transformative Experiences and Conceptual Change
Controversial issues have been established within the larger framework of civic education as an effective pedagogical approach to developing critical thinking in the classroom, preparing students with intellectual habits necessary for participation in scholarship, civic life and democracy. In this study, we found that a pedagogical intervention, Teaching for Transformative Experience in History, in some cases led to significantly higher engagement with political concepts beyond the classroom, and in other cases, the intervention led to significantly improved conceptual change. The study addresses some of the challenges presented by the research on civic education, providing a potential framework for developing pedagogical practice in history and social studies education that grounds a participatory, meaning-making process in curriculum design and assessment framed by controversial issues
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