τ\tau-Flavour Violation at the LHC

We study the conditions required for $\chi_2 \to \chi + \tau^\pm \mu^\mp$ decays to yield observable tau flavour violation at the LHC, for cosmologically interesting values of the neutralino relic density. These condition can be achieved in the framework of a SU(5) model with a see-saw mechanism that allows a possible coexistence of a LHC signal a low prediction for radiative LFV decays.Comment: 7 pages, 5 figures, Prepared for the proceedings of the workshop: "LC09: $e^+ e^-$ Physics at the TeV Scale and the Dark Matter Connection", 21-24 September 2009, Perugia, Ital

Transport in random quantum dot superlattices

We present a novel model to calculate single-electron states in random quantum dot superlattices made of wide-gap semiconductors. The source of disorder comes from the random arrangement of the quantum dots (configurational disorder) as well as spatial inhomogeneities of their shape (morphological disorder). Both types of disorder break translational symmetry and prevent the formation of minibands, as occurs in regimented arrays of quantum dots. The model correctly describes channel mixing and broadening of allowed energy bands due to elastic scattering by disorder

Light forces in ultracold photoassociation

We study the time-resolved photoassociation of ultracold sodium in an optical dipole trap. The photoassociation laser excites pairs of atoms to molecular states of large total angular momentum at high intensities (above 20 kW/cm$^{2}$). Such transitions are generally suppressed at ultracold temperatures by the centrifugal barriers for high partial waves. Time-resolved ionization measurements reveal that the atoms are accelerated by the dipole potential of the photoassociation beam. We change the collision energy by varying the potential depth, and observe a strong variation of the photoassociation rate. These results demonstrate the important role of light forces in cw photoassociation at high intensities.Comment: 7 pages, 3 figure

An etude for post-pandemic practice: The impact of the COVID-19 pandemic on practice methods and instrumental technique.

This paper considers how the pandemic-related concert-free time affected musicians' practice, specifically in relation to technique. A semi-structured interview was carried out on 22 musicians based in Switzerland (11 males, 11 females; 7 students, 15 non-students; 11 with school-aged children, 11 without school-aged children; 16 with teaching duties and 6 non-teachers). The amount of practice during the pandemic-related concert-free time was reported as different to usual by 91% and usual for only 9% of participants (p = 0.002). Forty-one percent of participants reported reduced, and 41% "fluctuating" amounts of practice. The proportion of practice time spent on technique was reported by 55% of participants to have increased and by only 9% to have decreased (p = 0.019). Of those who reported an increase in technique practice, 75% agreed this had a positive impact on technique, and only 8% disagreed (p = 0.037). Moreover, 58% considered this work to have changed their current and future practice. Participants were statistically more likely to report "never" watching online tutorials than "often" (p = 0.014), but, of those that did watch such material, 75% agreed that it had a positive impact upon their practice. Most participants created digital content during this period; only 5% produced no such material. An increased use of digital tools was reported by 55% of participants, 92% of whom described this as having a positive effect upon practice and only 8% were unsure (p = 0.022). However, in the unstructured discussion, the use of digital tools appears to be associated with mixed outcomes. Men reported significantly more frequent use of digital tools (91% vs. 45% describing this use as often, p = 0.038) and spent a larger proportion of time on technique relative to their pre-pandemic habits than women (p = 0.065); moreover, a trend indicated that more women than men created digital content in the form of tutorials (p = 0.095). The exceptional situation musicians experienced during the pandemic, which introduced new aspects to musical instrument practice, and accelerated changes already underway, could lead to future work that improves practice under "normal" conditions, and exposes discrepancies between certain demographic groups

Spinor Dynamics in an Antiferromagnetic Spin-1 Condensate

We observe coherent spin oscillations in an antiferromagnetic spin-1 Bose-Einstein condensate of sodium. The variation of the spin oscillations with magnetic field shows a clear signature of nonlinearity, in agreement with theory, which also predicts anharmonic oscillations near a critical magnetic field. Measurements of the magnetic phase diagram agree with predictions made in the approximation of a single spatial mode. The oscillation period yields the best measurement to date of the sodium spin-dependent interaction coefficient, determining that the difference between the sodium spin-dependent s-wave scattering lengths $a_{f=2}-a_{f=0}$ is $2.47\pm0.27$ Bohr radii.Comment: 5 pages, 2 figures. Changes: added reference, minor correction