solid-state

One of the biggest achievements of quantum physics was recasting our vision of the atom. Out was the early 1900s model of a solar system in miniature. Instead, quantum physics showed that electrons meander around the nucleus in clouds that look like tiny balloons. These balloons are known as atomic orbitals, and they come in all sorts of different shapes—perfectly round, two-lobed, clover-leaf-shaped. That’s all well and good for individual atoms, but when atoms come together to form something solid—like a chunk of metal, say—the outermost electrons in the atoms link arms and lose sight of the nucleus they came from, forming many oversized balloons that span the whole chunk of metal. Now, researchers have produced the first experimental evidence that one metal—and likely others in its class—have electrons that manage to preserve a more interesting, multi-lobed structure as they move around in a solid.

A powerful engine roils deep beneath our feet, converting energy in the Earth’s core into magnetic fields that shield us from the solar wind. Similar engines drive the magnetic activity of the sun, other stars and even other planets—all of which create magnetic fields that reinforce themselves and feed back into the engines to keep them running. Much about these engines, which scientists refer to as dynamos, remains unknown. That’s partly because the math behind them is doubly difficult, combining the complex equations of fluid motion with the equations that govern how electric and magnetic fields bend, twist, interact and propagate. But it’s also because lab-bound dynamos, which attempt to mimic the astrophysical versions, are expensive, dangerous and do not yet reliably produce the signature self-sustaining magnetic fields of real dynamos. Now, Victor Galitski, a Fellow of the Joint Quantum Institute (JQI), in collaboration with two other scientists, has proposed a radical new approach to studying dynamos, one that could be simpler and safer. The proposal, which was published Oct. 25 in Physical Review Letters, suggests harnessing the electrons in a centimeter-sized chunk of solid matter to emulate the fluid flows in ordinary dynamos.

Today’s networks use electronic circuits to store information and optical fibers to carry it, and quantum networks may benefit from a similar framework. Such networks would transmit qubits – quantum versions of ordinary bits – from place to place and would offer unbreakable security for the transmitted information. But researchers must first develop ways for qubits that are better at storing information to interact with individual packets of light called photons that are better at transporting it, a task achieved in conventional networks by electro-optic modulators that use electronic signals to modulate properties of light. Now, researchers in the group of Edo Waks have struck upon an interface between photons and single electrons that makes progress toward such a device.