Viewpoints

Neutrons Knock at the Cosmic Door

Neutrons Knock at the Cosmic Door

April 16, 2014

Wolfgang P. Schleich and Ernst Rasel

The quantum behavior of a neutron bouncing in the gravitational field of the Earth can improve what we know about dark energy and dark matter.

“Snowflake Crystal” Traps Light and Sound

April 14, 2014

Florian Marquardt

Experimentalists trap optical and acoustic oscillations together in a two dimensional structure that will make it easier to study their coupled behavior.

Controlling a Molecule's Fate

Controlling a Molecule’s Fate

April 7, 2014

Jian Wu

By selecting the intensity and duration of an ultrashort laser pulse, researchers are able to control the breakup of a molecule through the relation between its electrons and nuclei.

A Step Towards a Seismic Cloak

A Step Towards a Seismic Cloak

March 31, 2014

Ping Sheng

A large-scale experiment shows that a periodic array of boreholes embedded in the soil can deflect the energy of an incoming seismic wave.

Synopses

synopsis image

Bird Flocks Shatter on Impact

April 15, 2014

Simulations show that flocks hitting a wall disintegrate like brittle solids rather than splash like fluid drops.

synopsis image

Radiation-Belt Scattering in the Lab

April 10, 2014

Experiments in a laboratory recreate an interaction between electrons and plasma waves that may be responsible for large electron-flux variability in the Earth’s radiation belts.

synopsis image

High-Precision Terahertz Spectroscopy

April 9, 2014

The frequency-comb technique—a high-precision visible and near infrared spectroscopy method—has been extended to terahertz frequencies, allowing the characterization of a rotational transitions in a molecular gas with unprecedented accuracy.

synopsis image

Polar Swarms

April 8, 2014

A new theory can explain the formation of swarming patterns observed in ensembles of self-propelled polar particles.

Focus

Stopping Sound with Foam

Stopping Sound with Foam

April 11, 2014

Liquid foams can completely block ultrasound transmission of some frequencies, suggesting that foams are metamaterials that could be used for acoustic insulation.

Thermodynamics Confronts Quantum Mechanics

Thermodynamics Confronts Quantum Mechanics

April 4, 2014

Heat flow carried by electrons in a thermoelectric device requires a surprisingly wide “pipe”—a rare case where quantum effects have macroscopic consequences.

Notes from the Editors

Snapshots from the March Meeting—No-Photon Lasers, Hyperbolic Metamaterials, and More

Snapshots from the March Meeting—No-Photon Lasers, Hyperbolic Metamaterials, and More

March 17, 2014

Some 10,000 physicists descended on Denver, Colorado, for the 2014 APS March Meeting. Here’s a taste of the scientific findings presented this year.