We present a direct measurement of the speed of sound in a three-dimensional complex plasma —a room-temperature plasma that contains micrometer-sized particles as fourth component. In order to obtain an undisturbed system, the setup was placed under microgravity conditions on board the International Space Station. The speed of sound was measured with the help of Mach cones excited by a supersonic probe particle moving through the extended particle cloud at Mach numbers M 3. We use the Mach cone relation to infer the particle charge and compare with that predicted by standard theories. In addition, we compare our results with a numerical simulation. In both experiment and simulation, we observe a double Mach cone structure.

We describe the slippery behaviour of textured solids filled with oil, on which other liquids are found to slip and be removed easily. We describe the criteria for achieving this slippery behaviour, and illustrate the concept by two examples, namely the lotus effect (removal of dust by mobile drops) and the coffee stain effect.

An evaporating drop placed on a ratchet self-propels, as discovered by Linke et al. in 2006. Sublimating platelets do the same, and we discuss here a possible viscous mechanism for these motions. We report that the flow of vapor below the levitating material is rectified by the asymmetric teeth of the ratchet, in the direction of descending slopes along each tooth. As a consequence, the resulting viscous stress can entrain the material in the same direction, and we discuss the resulting self-propelling force.

In this communication we present a theoretical analysis of sound modes in non-magnetic solids or fluids in static and uniform magnetic field. The physics behind is based on the so-called gyromagnetic phenomena i.e., the appearance of a magnetic moment due to the intrinsic orbital moment of vibrational modes. The gyromagnetic contributions into the Lagrangian describing vibrations, conceptually dramatically modify the correlation (and linear response) functions of the displacements. Namely, in the response function one gets singular branching points (instead of simple poles which determine sound mode dispersion laws). In practical terms the corrections are very small although X-ray and optic experimental techniques have progressed to the point where observations of such very small effects are not hopeless.

Stunningly large exciton transfer rates in the light harvesting complex of photosynthesis, together with recent experimental 2D spectroscopic data, have spurred a vivid debate on the possible quantum origin of such efficiency. Here we show that configurations of a random molecular network that optimize constructive quantum interference from input to output site yield systematically shorter transfer times than classical transport induced by ambient dephasing noise.

It is shown that in the vicinity of magnetoelectric to multiferroic phase transitions the magnetoelectric coefficient α acquires gigantic values.

The ABC model is a simple diffusive one-dimensional non-equilibrium system which exhibits a phase transition. Here we show that the cumulants of the currents of particles through the system become singular near the phase transition. At the transition, they exhibit an anomalous dependence on the system size (an anomalous Fourier's law). An effective theory for the dynamics of the single mode which becomes unstable at the transition allows one to predict this anomalous scaling.

We discuss the interaction between nanometer-sized defects (atomic bubbles) and elementary excitations (phonons) in quantum fluids and solids. We observe that optical excitations in embedded metal atoms induce bubble expansions/contractions that create strongly localized phonon wave packets in the quantum matrix. We derive the structure and dynamics of these vibronic excitations from the experimental laser-induced fluorescence spectra of Au and Cu atoms in liquid and solid He. The atomic vibrations are found to be strongly damped on the 50 Å and 5 ps scales in agreement with pure hydrodynamic estimations.

TOTEM has measured the differential cross-section for elastic proton-proton scattering at the LHC energy of analysing data from a short run with dedicated large-β ^* optics. A single exponential fit with a slope B=(20.1±0.2 ^stat±0.3 ^syst) GeV ⁻² describes the range of the four-momentum transfer squared | t| from 0.02 to 0.33 GeV ². After the extrapolation to | t|=0, a total elastic scattering cross-section of (24.8±0.2 ^stat±1.2 ^syst) mb was obtained. Applying the optical theorem and using the luminosity measurement from CMS, a total proton-proton cross-section of (98.3±0.2 ^stat±2.8 ^syst) mb was deduced which is in good agreement with the expectation from the overall fit of previously measured data over a large range of center-of-mass energies. From the ...

We explore the effective long-range interaction of charged particles confined to a curved low-dimensional manifold using the example of a helical geometry. Opposite to the Coulomb interaction in free space the confined particles experience a force which is oscillating with the distance between the particles. This leads to stable equilibrium configurations and correspondingly induced bound states whose number is tunable with the parameters of the helix. We demonstrate the existence of a plethora of equilibria of few-body chains with different symmetry character that are allowed to freely move. An outline concerning the implications on many-body helical chains is provided.