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Matthew Reichl and Erich Mueller describe new way for lasers to generate flow in atomic clouds

Recent theoretical work by Reichl and Mueller (to be published in Physical Review A) describes how to engineer and probe an exotic state of matter called a "topological insulator" in a gas of atoms cooled to temperatures near absolute zero. Topological insulators have the remarkable property that they act like insulators in their interior but  can conduct along their surfaces or edges. They are not only of fundamental interest to physicists but have important applications in electronics and quantum computation. To engineer such a state, the authors imagine an experiment where ultracold atoms are trapped in a lattice with laser beams and made to behave like a topological insulator by modulating the lasers to change the shape of the lattice periodically in time. The smoking-gun signature of a topological insulator is the presence of "edge states"- conduction channels appearing at the boundaries of the system. Using computer simulations, the authors demonstrate how a clump of atoms released at the boundary will remain grouped together and will propagate- or "conduct"- along the boundary (see attached animation). Reichl and Mueller's proposal provides a straightforward and accessible way to generate and probe topological insulators in experiments using ultracold atoms. Such experiments will allow physicists to learn more about this fascinating state of matter.

atoms conduct along boundary of topological insulator system

Lawler, Kim & Davis reveal mysteries of the pseudogap

Michael Lawler, Eun-Ah Kim and Seamus Davis close in on the secret recipe for high-temperature superconductors. Their year-long research into the pseudogap transition to superconductors is published in the current issue of Science.

Details in the Chronicle article, from Brookhaven National Lab, and in the May 9 issue of Science.

superconductor

Cornell superconductivity research highlighted in Quanta Magazine

The April 30, 2014 Quanta Magazine feature article highlights inter-related efforts among researchers at the leading edge of high-temperature superconductivity. The Cornell research team of Eun-Ah Kim, Michael Lawler, and J.C. Séamus Davis play a key role in advancing theoretical models and developing methods to directly observe superconductors on the atomic scale.

Check out the article in Quanta: http://www.simonsfoundation.org/quanta/20140430-decoding-the-secrets-of-...

d-form factor density wave (dFF-DW)

Michelle Wang's group pioneers new method for studing multiple molecules at once

Michelle Wang and her lab have developed a new optical trap that allows them to study multiple molecules at once. Previous studies had used such traps to look at single molecules, such as DNA. This new device, called a nanophotonic standing wave array trap (nSWAT), can potentially trap hundreds of molecules at once. This allows researchers to complete experiments in a few days that used to take months.

Read more in the Chronicle.

Funding provided by the American Cancer Society, National Institutes of Health, National Science Foundation, and the Howard Hughes Medical Institute.

nSWAT by Robert Forties

Kyle Shen discovers atomic-scale switch in metal oxides

Kyle Shen and a team from Cornell and Brookhaven National Lab have discovered a new property of metal oxides that can act like a switch. Using a unique laboratory setup that allows for precision growth and measurement of the materials, the group discovered that varying how thick the layers of atoms are can determine whether the material acts as a metal or an insulator. This has exciting potential applications in atomic-scale electronics and superconductivity.

Read more in the Chronicle.

anthanum nickelate

David Mermin says QBism puts the scientist back into science

A new understanding of quantum mechanics restores the balance between scientists and the objects they study, says David Mermin, the Horace White professor of physics emeritus, in this article in Nature.

“They call their new point of view ‘QBism’: Q is for quantum and B is for Bayesian — a view of probability that includes an agent who makes bets and updates odds. QBism attributes the muddle at the foundations of quantum mechanics to our unacknowledged removal of the scientist from the science,” Mermin says.

David Mermin