Topological Quantum Optics in Two-Dimensional Atomic Arrays

July 20, 2017

Snapshot of the time evolution (at t = 5.7 Γ0−1) of the system as an atom on the edge (red star) is driven by a laser (inset). The color code shows the excitation probability | 〈ψ(t)|σ1+ 〉 |2 + | 〈ψ(t)|σ1- 〉 |2at each atomic site i = 1,..., N. Approximately 96% of the emitted excitation is coupled into the forward direction and scattering into bulk and backward edge modes is strongly suppressed.


Control and Measure of Electron Spin Voltage

July 16, 2017

Researchers used atomic-size defects in diamonds to detect and measure magnetic fields generated by spin waves. (Image courtesy of Peter and Ryan Allen/Harvard University.)

Information technologies of the future will likely use electron spin — rather than electron charge — to carry information. But first, scientists need to better understand how to control spin and learn to build the spin equivalent of electronic components, from spin transistors, to spin gates and circuits.


How Eggs Got Their Shapes

June 23, 2017
bird eggs of various shapes

Image credit: Harvard Museum of Comparative Zoology

The evolution of the amniotic egg — complete with membrane and shell — was key to vertebrates leaving the oceans and colonizing the land and air. Now, 360 million years later, bird eggs come in all shapes and sizes, from the almost perfectly spherical eggs of brown hawk- owls to the tear-drop shape of sandpipers’ eggs. The question is, how and why did this diversity in shape evolve?


Bloch Oscillations in the Absence of a Lattice

June 8, 2017

Concept of the experiment, A: an ensemble of 1D Bose gases in tubes formed by two pairs of counterpropagating and interfering laser beams. In each tube, a single strongly interacting impurity (green sphere) is immersed in the correlated host gas (black spheres) and is accelerated by gravity (green arrow). Inset: Scattering length as for collisions between the atoms in the host gas (dashed line) and between the impurity and the host atoms (solid line) as a function of the magnetic field B.* [Reprinted by permission from AAAS ©2017.]