Articles in 2010

Ultrafast spectroscopy reveals the many-body effects behind the metallization of a one-dimensional Mott insulator. Unlike in ultracold gases, these femtosecond excitation studies of quantum dynamics occur at room temperature.

Detecting and counting individual microwave photons is important for processing quantum information, but it is made challenging by an absence of detectors that are sensitive enough to radiation at this wavelength. Correlations between microwave photons have now been measured using a series of amplifiers and digital analysis.

High-order harmonic generation is a nonlinear optical process that enables the creation of light pulses at frequencies much higher than that from a seed laser. The host medium for this interaction is typically a gas. Now, the process has been observed in a bulk crystalline solid with important implications for attosecond science.

The pseudogap state in the cuprate superconductors shows signs of electronic pair formation above the superconducting temperature. Is it just a ‘precursor’ state or a separate (and competing) state? In fact, both interpretations seem to be correct.

Engineered decoherence enables tracking of multipartite entanglement as a quantum state decays.

A successful year for the Large Hadron Collider has culminated in its first lead-ion collisions.

Precisely what are the electrons in a high-temperature superconductor doing before they superconduct? Strong electronic correlations may give rise to composite rather than fractionalized excitations, as is typical in other strongly coupled systems such as quark matter.

A study of a non-liquid glass former reveals a correlation length that decreases as the transition temperature is approached from above, which is the opposite of what is expected. It suggests that ‘strong’ and ‘fragile’ liquids exist on opposite sides of an order–disorder phase transition.

If vortex cores within a superconductor can trap electrostatic charge, the cores will experience a repulsive Coulomb interaction. Evidence from NMR measurements indeed suggests that above some threshold magnetic field, the Abrikosov vortex lattice becomes unstable.

Bound pairs consisting of a vortex and an antivortex are expected to dominate the low-temperature physics in a variety of two-dimensional systems. The observation of such bound pairs, however, remains elusive. A study now establishes non-equilibrium condensates of exciton-polaritons as a platform for exploring the physics of vortex–antivortex pairs.

Simply cooling down an artificial spin-ice does not necessarily lead to ground-state magnetic order. But as-grown artificial square ice reaches a thermodynamic ground state, with monopole dynamics possibly involved in the thermalization.

Rydberg molecules, which consist of one atom in its electronic ground state and one in a highly excited state, can extend to the size of a virus. But size is only one oddity of these molecules. As has now been demonstrated, the chemical bond that holds the atoms together in this fragile molecule can be coherently controlled using laser light.

Rydberg molecules—which involve atoms in highly excited electronic states and can be as large as 100 nanometres—have been created recently in cold gases of rubidium atoms. New work demonstrates that the inter-atomic interactions in these long-range molecules can be manipulated coherently, enabling controlled ‘making and breaking’ of the bond using laser light.