Breakthrough of the year. Global warming, hotter than ever

Climate change, a perennial runner-up for Breakthrough of the Year, broke from the pack this year--both in the pages of this section and in the public arena.     

Diffusion of nonequilibrium quasi-particles in a cuprate superconductor

We report a transport study of nonequilibrium quasi-particles in a high-transition-temperature cuprate superconductor using the transient grating technique. Low-intensity laser excitation (at a photon energy of 1.5 electron volts) was used to introduce a spatially periodic density of quasi-particles into a high-quality untwinned single crystal of YBa2Cu3O6.5. Probing the evolution of the initial density through space and time yielded the quasi-particle diffusion coefficient and the inelastic and elastic scattering rates. The technique reported here is potentially applicable to precision measurements of quasi-particle dynamics not only in cuprate superconductors but in other electronic systems as well.     

Human genome. Finally, the book of life and instructions for navigating it

The race is over. On 26 June, to much fanfare, two rival teams announced that they had each completed a version of the "book of life"--a rough draft of the complete human genetic code. So what, exactly, is in these two different volumes, and how will they fine-tune it so that everyone from workaday biologists to pharmaceutical giants can mine its gold?     

Spins in the vortices of a high-temperature superconductor

Neutron scattering is used to characterize the magnetism of the vortices for the optimally doped high-temperature superconductor La(2-x)Sr(x)CuO4 (x = 0.163) in an applied magnetic field. As temperature is reduced, low-frequency spin fluctuations first disappear with the loss of vortex mobility, but then reappear. We find that the vortex state can be regarded as an inhomogeneous mixture of a superconducting spin fluid and a material containing a nearly ordered antiferromagnet. These experiments show that as for many other properties of cuprate superconductors, the important underlying microscopic forces are magnetic.