Physical Review Applied Call for Papers APS is now accepting submissions for Physical Review Applied, the newest member of thePhysical Review family. Dedicated to publishing the highest quality research at the intersection of physics and engineering, Physical Review Applied will debut in early 2014. Troy Shinbrot, Professor of Biomedical Engineering at Rutgers University, is the Editor forPhysical Review Applied and will work closely with a distinguished and diverse Editorial Board. Professor Shinbrot received his Ph.D. in Physics from the University of Maryland and held positions in industry before joining the Rutgers faculty in 1998. His research focuses on computational biology and multiphase flow. He was selected as an APS Outstanding Referee in 2008. Physical Review Applied expands the current APS family of journals to provide comprehensive coverage of applied physics research. This new journal will include Letters, Research Articles, and Review Articles and follow the same high-quality peer-review process as the other Physical Review journals. More information about Physical Review Applied, including manuscript submission, is available online at journals.aps.org/prapplied. Contact: prapplied@aps.org The American Physical Society (www.aps.org) is a non-profit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy and international activities. APS represents 50,000 members, including physicists in academia, national laboratories and industry in the United States and throughout the world. Society offices are located in College Park, MD (Headquarters), Ridge, NY, and Washington, DC.

APS Physics Tip Sheet – Dec 10, 2013

In this issue: Dark Matter Signatures?, Detecting Molecules on a Chip, Liquid-Crystal Flowers, Counting Atoms Up To 1200

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Dark Matter Signatures?

Results from one the leading dark-matter-detection collaborations have revealed potential signatures of dark-matter particles, but more recent experiments suggest dark matter has yet to be detected.

The Cryogenic Dark Matter Search (CDMS) experiment at Fermilab in Illinois and the Large Underground Xenon (LUX) experiment in South Dakota have reported results from their most extensive search for dark-matter candidate particles called Weakly Interacting Massive Particles (WIMPs). In underground facilities providing shielding from cosmic radiation, CDMS detectors have recorded three blips that could signal a dark-matter particle hitting the detector. The finding would point to the existence of WIMPs nine times as massive as protons. But more recently, a similar experiment at the Large Underground Xenon (LUX) experiment in South Dakota, which nominally features a much higher sensitivity, announced it has seen no evidence for dark matter. Scientists are still debating whether the new LUX result rules out the CDMS finding. 

* CDMS Collaboration (contact author: Enectali Figueroa-Feliciano) et al, “Silicon detector dark matter results from the final exposure of CDMS II”, Physical Review Letters (expected publication date: Dec 16)

* LUX Collaboration (contact author: Blair Edwards), “First results from the LUX dark matter experiment at the Sanford Underground Research Facility”, http://arxiv.org/abs/1310.8214

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Detecting Molecules on a Chip

A new setup allows the detection of molecules trapped on the surface of a microchip.

Modern labs-on-a-chip can perform experiments on atoms or ions trapped on the surface of microchips, with applications ranging from quantum computing to gravitation sensing. Molecules would offer much richer properties than atoms and ions, but molecule-chips have lagged behind, partly because molecules are more difficult to cool, control and observe. A research group at the Fritz Haber Institute of the Max Planck Society, Germany, has developed the first on-chip molecular detector. The researchers use a laser to ionize a few carbon-monoxide molecules trapped on the chip, and then image the resulting ion cloud on a phosphor screen several centimeters above the chip.

* S Marx, Gabriele Santambrogio (contact author) et al, “Imaging cold molecules on a chip”, Physical Review Letters (expected publication date: Dec 12)

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Liquid-Crystal Flowers

Researchers at the University of Pennsylvania have demonstrated a method for engineering flower-shaped liquid-crystal structures, in which the molecules are aligned around multiple ellipses resembling the petals on a daisy. The structures could be used to make microlenses that focus light efficiently. 

* DA Beller, Randal D Kamien (contact author) et al, “Focal conic flower textures at curved interfaces”, Physical Review X (expected publication date: Dec 10)

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Counting Atoms Up To 1200

Many experiments with cold atoms rely on the exact determination of the number of atoms, in particular high-precision metrology applications like atomic clocks. Researchers at the University of Heidelberg have set a record for the number of atoms that can be counted with single-atom precision. By monitoring the light emitted by an ensemble of cold, trapped atoms, the researchers were able to count up to 1200 atoms, improving on the previous record by almost an order of magnitude. 

* DB Hume (contact author) et al, “Accurate atom counting in mesoscopic ensembles”, Physical Review Letters (expected publication date: Dec 16)

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