Tuesday, June 3, 2014

Novel Dark Matter Searches, Identifying Muzzle Flashes, and more at the 2014 APS DAMOP annual meeting

Contact:
James Riordon

COLLEGE PARK, MD - The American Physical Society’s 2014 Division of Atomic, Molecular and Optical Physics (DAMOP) meeting focuses on the latest research into the control and manipulation of atoms, molecules, charged particles and light, through precision measurements and calculations of their properties, and through the invention of new ways to generate light with specific properties. 

The 2014 DAMOP annual meeting takes place June 2 to June 6 at the Monona Terrace Convention Center in Madison, Wisconsin. A full schedule of meeting talks and posters is available at http://meeting.aps.org/Meeting/DAMOP14/APS_epitome

Here is a sampling of presentations at this year’s DAMOP meeting

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SEARCHING FOR DARK MATTER WITH MAGNETOMETERS AND ATOMIC CLOCKS
A worldwide network of sensitive magnetic field detectors could soon solve a vexing dark matter puzzle. No experiment has convincingly detected particles of dark matter, but we may be able to see signs of it by searching for the passage of enormous structures in space with distinct and differing characteristics. Although the structures, known as domains, are not directly detectable, the walls between them may be. Derek Kimball (California State University - East Bay) will describe a prototype magnetometer (Thursday, June 5, http://meetings.aps.org/Meeting/DAMOP14/Session/M6.4), constructed by a team consisting entirely of undergraduate students, that will be the basis for the planned Global Network of Optical Magnetometers to search for Exotic physics (GNOME). Andrei Derevianko (University of Nevada, Reno) will present a similar project that instead relies on a network of atomic clocks to detect the passage of dark matter domain walls (Wednesday, June 4,http://meetings.aps.org/Meeting/DAMOP14/Session/H6.9).

THEORETICAL CHARACTERIZATION OF MUZZLE FLASHES
With properly formulated propellant mixtures, it could be possible to minimize the visibility of muzzle flashes that come from firing weapons. Potentially, that would make soldiers less vulnerable on the field of battle. David Kashinski (United States Military Academy) and colleagues are working to develop theoretical models to predict the spectrum emitted by weapon muzzle flashes, which may lead to stealthier weapons, or perhaps characteristic flashes that could distinguish between friendly and enemy fire. (Wednesday, June 4, http://meetings.aps.org/Meeting/DAMOP14/Session/K1.121)

HIGH-VOLTAGE, HIGH-POWER GASEOUS ELECTRONICS SWITCH FOR ELECTRIC GRID POWER CONVERSION
Direct current (DC) is more efficient when it comes to high voltage, long distance power transmission, but alternating current (AC) is typically produced in large generators and is better for converting from high voltages to reasonable levels at the point of use. The lack of convenient converters from AC to DC and back has meant that today’s power grids are exclusively AC. Timothy J. Sommerer (General Electric Research, Niskayuna, New York) will discuss progress towards a high-power gas switch that could solve the conversion problems and allow grids to combine high voltage DC transmission with lower voltage AC circuitry, improving efficiency without sacrificing practicality. (Wednesday, June 4, http://meetings.aps.org/Meeting/DAMOP14/Session/H8.3)

Other intriguing talks at the 2014 DAMOP annual meeting:

FORCE DETECTION WITH AN OPTICALLY LEVITATED MICROSPHERE IN VACUUM
Thursday, June 5

THE DEVELOPMENT OF ATOM-INTERFEROMETRY-BASED INSTRUMENTS FOR SPACE MISSIONS

ATOM INTERFEROMETERY ON GROUND AND IN SPACE
Thursday, June 5

TOWARDS A CAVITY ELECTROMAGNETICALLY INDUCED TRANSPARENCY BASED QUANTUM GATE
Thursday, June 5

OPTIMIZATION OF A QUANTUM MEMORY WITH TELECOM-WAVELENGTH CONVERSION
Tuesday, June 3

A WIDE-FIELD NV DIAMOND MAGNETIC IMAGER FOR HIGHLY PARALLEL DETECTION OF RARE BIOLOGICAL TARGETS
Tuesday, June 3

A QUANTUM NETWORK OF CLOCKS
Wednesday, June 4

ULTRAFAST GENERATION OF LARGE SCHRODINGER CAT STATES
Wednesday, June 4

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ABOUT APS
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.
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New Four-Quark State Confirmed, Understanding Marine Biodiversity, The Physics of Adhesives

APS Physics Tip Sheet – Jun 3, 2014

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New Four-Quark State Confirmed

The LHCb experiment provides conclusive evidence for the existence of a new four-quark particle called Z(4430).

In 2013, two collaborations (BESIII in Chine and Belle in Japan) reported the experimental signatures of a new particle called ZC(3900) that contained four quarks, defying the conventional wisdom that quarks only combine in pairs or triplets. LHCb—one of seven particle physics detector experiments collecting data at the Large Hadron Collider accelerator at CERN— has now reported a definitive observation of another four quark particle called Z(4430), for which some experimental hints were first collected by Belle in 2008. The analysis of the decay of B mesons generated by LHC’s collisions has revealed that Z(4330) is a bound state of four quarks and characterized its spin, charge and symmetry.

* LHCb Collaboration (contact author: Tomasz Skwarnicki), “Observation of the resonant character of the Z(4430) state,” Physical Review Letters (expected publication date: Jun 4)
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Understanding Marine Biodiversity

​A new model based on network theory explains why marine biodiversity has grown at a different pace than continental biodiversity.

Biodiversity on land has been expanding exponentially, from few species at the beginning of the Phanerozoic to some million species today. But the growth dynamics of marine life has been very different: According to fossil records, about 500 million years ago the number of marine species began growing exponentially and then leveled off for 200 million years, before exploding again. A team of researchers from Germany and Switzerland has now constructed a model of species dependence that could explain this observation. The authors’ analysis, based on network dynamics, shows that a biodiversity stagnation can occur when species at the top of the ecological pyramid are dependent on only a few species at the bottom, whose extinctions can thus wipe out the whole ecosystem. Applying their model in combination with paleontological datasets, the authors argue this situation explains the observed slow-down of marine biodiversity. 
* F. Stollmeier, T. Geisel, and Jan Nagler (contact author), “Possible origin of stagnation and variability of Earth’s biodiversity,” Physical Review Letter (expected publication date: June 5)
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The Physics of Adhesives

​A new model predicts the force needed to peel off a thin film from a surface.
From Scotch™ tape and cling wrap to the footpads that allow spiders and geckos to climb vertical walls, dry adhesives serve as removable joints between dissimilar materials. Adhesion is often determined by weak bonds (of van der Waals type) and detachment is governed by the collective failure of such bonds. Researchers in Sweden have modeled the microscopic process of peeling off a thin film adhering to a surface with small bumps. The results show that tiny, random fluctuations in the bonds between the film and the surface can cause the film to peel off in a series of discrete steps, rather than in one continuous motion. Compared to previous work, the new model could provide better estimates of the forces needed to detach thin films from surfaces. This would be particularly important for nanotechnology applications, helping scientists find optimal ways to peel away sheets of graphene and other substances in the lab.

* Stefan B. Lindström (contact author), L. Johansson, and N.R. Karlsson, “Metastable states and activated dynamics in thin-film adhesion to patterned surfaces,” Physical Review E (expected publication date: Jun 6)
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Journal articles and preprints are available to journalists on request. 
Contact: Matteo Rini Tel: +1 631 591 4224 (office), +1 646 288 5441 (cell), email: mrini@aps.org

Matteo Rini, PhD 
Deputy Editor, Physics 

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