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We study the dynamical structure factor of the spin-1 pyrochlore material NaCaNi_{2}F_{7}, which is well described by a weakly perturbed nearest-neighbour Heisenberg Hamiltonian, Our three approaches-molecular dynamics simulations, stochastic dynamical theory, and linear spin wave theory-reproduce remarkably well the momentum dependence of the experimental inelastic neutron scattering intensity as well as its energy dependence with the exception of the lowest energies. We discuss two surprising aspects and their implications for quantum spin liquids in general: the complete lack of sharp quasiparticle excitations in momentum space and the success of the linear spin wave theory in a regime where it would be expected to fail for several reasons.

The combination of electronic correlation and spin-orbit coupling is thought to precipitate a variety of highly unusual electronic phases in solids, including topological and quantum spin liquid states. We report a Raman scattering study that provides evidence for unconventional excitations in α-RuCl_{3}, a spin-orbit coupled Mott insulator on the honeycomb lattice. In particular, our measurements reveal unusual magnetic scattering, typified by a broad continuum. The temperature dependence of this continuum is evident over a large scale compared to the magnetic ordering temperature, suggestive of frustrated magnetic interactions. This is confirmed through an analysis of the phonon linewidths, which show a related anomaly due to spin-phonon coupling. These observations are in line with theoretical expectations for the Heisenberg-Kitaev model and suggest that α-RuCl_{3} may be close to a quantum spin liquid ground state.

Budding yeast is a unicellular organism which undergoes an asymmetric cell division. Successful completion of this process requires the assembly and translocation of the mitotic spindle from the mother cavity interior to the plane of cell division prior to segregation of the chromosomes. We use confocal fluorescence microscopy and automated image analysis algorithms to quantify the movement of the mitotic spindle, throughout the cell life cycle, at high spatial and temporal resolution. By selecting fluorescent proteins which specifically label the spindle poles and cell periphery, the spindle dynamics can be characterised within a coordinate system relevant to the cell division. Spindle length and orientation as well as the mother and bud cavity volumes have been extensively quantified in wild type cells. Our observations reveal fluctuations in spindle length and angle in the short pre-anaphase spindles that are distinct from longer anaphase spindles. Furthermore they indicate an apparent correlation between cell morphology and spindle dynamics. To elucidate the contributions of individual intercellular force generators to the fluctuations observed during spindle assembly and positioning, we apply the above methods to cells bearing deletions of the kinesins cin8, kip1 and kip3. It is expected that this work will ultimately enable a connection between observable single cell dynamics and biochemical signal pathways measurable by bulk assays.