Volume 5 Issue 5, May 2009

Careful study of the moments leading up to pinch-off of air bubbles in water reveals rich and intricate dynamics controlling their evolution, and could spark re-examination of assumptions about the nature of the formation of singularities in many physical systems.

Experiments in ¹³C nanotubes reveal surprisingly strong nuclear spin effects that, if properly harnessed, could provide a mechanism for manipulation and storage of quantum information.

The common picture of how atoms and molecules are ionized in intense laser fields has had decades of success. However, the observation of an unexpected but apparently universal low-energy photoionization feature suggests this picture is incomplete.

Hyperfine coupling to nuclei can be detrimental to the coherence of electron spins, but properly harnessed it can provide a mechanism for manipulation and storage of quantum information. Spin-blockade measurements in ¹³C carbon nanotubes now show surprisingly strong effects of electron–nuclear interaction, with a hyperfine coupling two orders of magnitude larger than previously anticipated.

The remarkably strong coupling between the electronic and vibrational modes of suspended carbon nanotube quantum dots provides a new way of studying quantized mechanical motion.

The creation and annihilation of magnetic vortex–antivortex pairs has been predicted to have a role in magnetic switching in permalloy nanostructures, but has never previously been observed. High-speed X-ray microscopy now enables the evolution and dynamics of this process to be studied in detail.

The discovery of an overlooked but apparently ubiquitous spike in the mid-infrared photoelectron spectra of molecular and atomic gases suggests that we don’t know as much as we thought we did about the ionization of matter in strong fields.

The strength of interparticle interactions in cold gases can be tuned using magnetic fields. This widely used approach is now combined with laser manipulation, providing additional flexibility, such as the possibility of spatially modulating the interaction strength on short length scales.

Conventional wisdom suggests that it should be impossible for information to pass across a singularity. A study of the behaviour of air bubbles as they disconnect from a submerged nozzle suggests that this isn’t always the case.

When a single strand of DNA is threaded through a nanopore, a direct test of the effect of pore size indicates that a hydrodynamic model for the process should include the coupled Poisson–Boltzmann and Stokes equations.

The ability to coherently manipulate single electrons and photons is vital for quantum information processing. Experiments now demonstrate optical initialization, manipulation and probing of a single quantum dot on femtosecond timescales, revealing signatures of interaction effects, optical gain and the ability to change the number of quanta in a light pulse by one.

When the length of a light pulse approaches that of just a few wavelengths, the difference in the phase of its field relative to its overall shape, or envelope becomes important in how the pulse interacts with matter. Accurate measurements of this carrier-envelope phase previously required averaging over many separate pulses. Now it can be measured in one shot.

The extreme fields generated when a high-intensity laser or relativistic electron passes through a plasma offer the potential to accelerate particles over shorter distances than is possible with conventional accelerators. A new study suggests that driving a plasma with protons rather than electrons could be the key to generating TeV electron beams by this process.