Novel sensors exploit electromagnetically-induced transparency in nearly-perfect synthetic diamond

LC14916 - Electromagnetically-induced transparency (EIT) is a powerful optical technique which can turn an ordinarily opaque medium completely transparent. Numerous applications based on EIT are being pursued, including ultra-low-power optical transistors and delay lines, electromagnetic field sensors, and atomic clocks. Atomic gases offer an excellent testbed for EIT research, but they are difficult to employ in practical devices and performance has lagged in the few solid-state systems where EIT has previously been observed.

Researchers now are reporting observation of EIT in a new solid-state system: nearly-perfect synthetic diamonds doped with nitrogen-vacancy (NV) color centers. This observation is exciting because of the possibility to leverage standard semiconductor fabrication techniques to realize scalable photonic networks using an EIT-active medium.

As an example of a potential application, the authors showed that diamond-EIT devices are capable of simultaneously sensing magnetic and electric fields entirely optically, with sensitivity competitive with current state-of-the-art technology and good long-term stability. The sensor may be immediately applied in fundamental-physics experiments. More generally, the new EIT system may lead to a new class of low-power, nonlinear optical devices, impacting research in solid-state physics, atomic physics, optoelectronic engineering, and nanophotonics.

What Made the Universe Magnetic?

LV13567 - The Universe is magnetic. Astrophysical observations strongly suggest the all galaxies, clusters of galaxies, and even empty space between galaxy clusters are pervaded by magnetic fields. In this paper, we solve the longstanding problem of the origin of such magnetic fields, by showing how they naturally emerge from ''inflation'', an incredibly fast expansion of the universe happened soon after the Big Bang. Theorized by the American physicist Alan Guth in the 80's and experimentally confirmed by the NASA satellite ''Wilkinson Microwave Anisotropy Probe'' in 2006, inflation, beside to explain some major technical problems in cosmology, generates the seeds for the growth of galaxies and, ultimately stars, planets, and ourselves. In our paper, we show that inflation is also able to excite tiny dormant magnetic fluctuations ever-present in the vacuum, which are then amplified and stretched up to overfill the entire Universe. Inflation then, can number among its achievements also a simple explanation of why the Universe is magnetic

Einstein in a Box

LC14467 - Our work provides the most direct realization of an experiment proposed by Einstein almost 90 years ago, and makes a major advance in the worldwide effort on “quantum simulation”.

In 1925 Einstein predicted that, at temperatures near absolute zero, particles in a gas can lose their individuality and unify into a single quantum object - a new state of matter now called a Bose-Einstein condensate (BEC). A BEC was finally realized in an atomic gas in 1995, and is now widely used for studies of exotic quantum phenomena. Beyond testing Einstein’s hypothesis, BECs offer a flexible experimental platform for controlled simulation of many related phenomena that occur in other physical systems, from superconductors to neutron stars.

However, while both the condensate envisioned by Einstein and real materials such as superconductors are spatially uniform, atomic BECs are normally produced in parabolic-shaped atom traps with spatially varying atomic density. This often fundamentally alters the behavior of the gas and makes a direct comparison with theories of uniform systems difficult. We have now realized the first atomic BEC in a spatially uniform gas, confined in an “optical box” trap. This provides the textbook realization of Einstein’s original proposal and will in the future allow a more direct simulation of other quantum systems.

Introducing the THEDAR: a novel thermal imaging system

LZ13491 - Imagine a person in a room with absorbing walls. Because, an absorber is also a good thermal emitter, the walls radiate a random electromagnetic field. At high temperature, the thermal radiations dazzle him so that the person cannot distinguish any objects in the room. But now, imagine that their eyes are replaced by two antennas that measure and cross-correlate the wavefields in time. The result is amazing : it will appear to him that one eye illuminates the environment with a short electromagnetic pulse while the other eye captures the backscattered field. As a result, the person can "see" the details of the room because the two “antenna eyes” mimic a RADAR that resolves in time the echoes from objects. In this paper, we have demonstrated experimentally at microwave range this property. The influence of the temperature of the walls is explored and is well predicted by the black-body theory. Based on this principle, we introduce and experimentally validate a new concept of imaging systems : the THEDAR (thermal emission detection and ranging). Since THEDAR does not need any power emission, it opens a new way for “green” electromagnetic imaging in many field (medical, remote sensing, nano imaging) and could have fascinating applications in radio astronomy using cosmic microwave background radiation.

Physics of Gorilla Glass

LB13930 -

Prince Rupert's Drops

Prince Rupert’s drops, also known as Dutch tears, are tadpole-shaped glass droplets that are able to withstand strong blows to their main bodies, but explosively crumble upon the slightest damage to their tails. Similar behavior, albeit less spectacular, is observed in various everyday situations and exploited in industrial applications such as safety glass or “Gorilla glass” covers for smartphones. This, sometimes phenomenal, response is due to a persistent stress remaining in the material, which cannot fully relax to equilibrium and is, often deliberately, inflicted during the production process, e.g. by fast solidification from the melt. These macroscopic material properties are thus imprinted by the history- or process-dependent microstructure and cannot be relieved. Despite large efforts, residual stresses have long defied a thorough understanding. Now, experiments, simulations and theoretical calculations have been combined to shed light on the microscopic origin and the generic mechanism leading to macroscopic residual stresses in glasses and hence their amazing, but also scientific and technologically interesting, rheological behavior.

Live Press Conference Webcasts from the 2013 APS April Meeting

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Physics Press Conference and Webcast Schedule
American Physical Society April Meeting
Denver, CO, April 13 – April 16
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COLLEGE PARK, MD, April 10, 2013 -- The following press conferences will take place during the April Meeting of the American Physical Society, April 13 – April 16, in Plaza Court 7 of the  of the Sheraton Denver Downtown Hotel.

The press conferences will be webcast live for journalists who wish to participate remotely. To register for the APS April Meeting webcasts, go to http://www.apswebcasting.com

BRIEF SCHEDULE OF PRESS CONFERENCES
Note: all times listed are Mountain Daylight Time (GMT-06)

Saturday, April 13
--9:00 a.m. MDT, Digging For Higgs: Latest Results from the High-Energy Physics Frontier
--11:00 a.m. MDT, Honey, I Shrunk the Proton!: Updates on an Unsolved Scientific Mystery
--2:00 p.m. MDT, Gravitational Wave Detection: Future Prospects and New Technology

Sunday, April 14
--TBD: 10:00 a.m. OR 4:00 p.m. MDT, The Promise and Challenge of Renewable Electricity
--11:00 a.m. MDT, Beyond the Standard Model: In Search of Susy and Other New Physics
--2:00 p.m. MDT, Exploding Stars and Life on Earth: Exploring the Distant Links

Monday, April 15
--11:30 a.m. MDT, Physics for the Public
--2:00 p.m. MDT, American Science and America's Future
--3:30 p.m. MDT, Celebrating Niels Bohr: New Insights on the Man and the Quantum World he Envisioned

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DIGGING FOR HIGGS: LATEST RESULTS FROM THE HIGH-ENERGY PHYSICS FRONTIER
Saturday, April 13, 9:00 a.m. MDT
The particle that appears to be the long-sought Higgs boson has inspired a wealth of research into the new particle’s properties. Scientists will discuss the status of current Higgs searches, and what finding the Higgs means for physics. Michael Peskin (B2.00003) of SLAC and Stanford University will talk about the predicted properties of the Higgs boson that are now being tested at the Large Hadron Collider (LHC). He will also discuss the future of high-precision studies of this particle and its possible partners, and the road that the Higgs boson provides to the exploration of the larger mysteries of particle physics. Thomas Koffas (B2.00001) of Carleton University will present an overview of efforts at identifying the Higgs, featuring findings from both CMS and ATLAS, the large collaborations that use the LHC. And Markus Klute (B2.00002) of MIT will discuss the status of direct searches for a Higgs boson with properties beyond those predicted by the Standard Model.
B2.00002 – http://meetings.aps.org/Meeting/APR13/Event/194971
B2.00001 – http://meetings.aps.org/Meeting/APR13/Event/193695
B2.00003 - http://meetings.aps.org/Meeting/APR13/Event/191961

HONEY, I SHRUNK THE PROTON!: UPDATES ON AN UNSOLVED SCIENTIFIC MYSTERY
Saturday, April 13, 11:00 a.m. MDT
In 2010, scientists performing measurements on an exotic form of hydrogen found that the proton at the center of the atom was smaller than expected. Despite many subsequent studies, the mysterious result still defies explanation. Three scientists at the heart of the “proton radius puzzle” will discuss recent results and ongoing research. John Arrington (Q5.00003) of Argonne National Laboratory will summarize the state of existing measurements of the proton radius and discuss ways the measurements might be improved. Randolf Pohl (C12.00007) of the Max Planck Institute of Quantum Optics is a member of the team that first measured the smaller proton.  He will discuss his team’s most recent results that confirm the 2010 measurements. And Jan Bernauer of MIT, who has performed recent measurements of the proton radius that conflict with the new results of Pohl’s team, will discuss his team’s experiment and possible explanations for the discrepancy.  All three scientists will describe future research efforts that might provide a clue to solving the mystery.
Q5.00003 – http://meetings.aps.org/Meeting/APR13/Event/192737
C12.00007 – http://meetings.aps.org/Meeting/APR13/Event/192121

GRAVITATIONAL WAVE DETECTION: FUTURE PROSPECTS AND NEW TECHNOLOGY
Saturday, April 13, 2:00 p.m. MDT
Gravitational waves are ripples in the fabric of space that Einstein’s Relativity tells us must be produced in violent astrophysical events such as black hole collisions. Advanced LIGO (Laser Interferometer Gravitational Wave Observatory) and Advanced Virgo are enormous, kilometer-long detectors that are almost certain to detect gravitational waves in the next few years. Such devices will open up an entirely new window on the cosmos, essentially acting as gravitational wave telescopes. Gabriela Gonzalez (Louisiana State University, H8.00005) will describe the currently projected schedule, sensitivity, and sky localization accuracy for the gravitational wave detector network in the next decade. Lisa Barsotti (Massachusetts Institute of Technology, LIGO Laboratory, G5.00002) will show how mature technology can be used to push precision measurement of gravitational waves beyond the standard quantum limit by means of squeezed states of light, and current ideas on how to integrate this technology into Advanced LIGO. Andrew Geraci (University of Nevada, Reno, L10.00008) will describe a novel method for gravitational wave detection using laser-cooled, optically-levitated sensors, which could exceed the sensitivity of next-generation gravitational wave observatories by a factor of ten or more.
H8.00005 – http://meetings.aps.org/Meeting/APR13/Event/192416
G5.00002 – http://meetings.aps.org/Meeting/APR13/Event/193858
L10.00008 – http://meetings.aps.org/Meeting/APR13/Event/192669

THE PROMISE AND CHALLENGE OF RENEWABLE ELECTRICITY
Sunday, April 14,  time TBD -- 10:00 a.m. OR 4:00p.m. MDT
We face many challenges in the process of moving from limited fossil fuel sources for most of our energy needs to primarily renewable electricity. Trieu Mai (H6.00002) of the National Renewable Energy Laboratory will contemplate the extent to which renewable energy supply can meet the electricity demands of the continental US. Michael Tamor (J6.00001) of the Ford Motor Company will discuss the use of electricity as a sustainable transportation fuel in electric and hybrid vehicles.
J6.00001 – http://meetings.aps.org/Meeting/APR13/Event/192501
H6.00002 – http://meetings.aps.org/Meeting/APR13/Event/192405

BEYOND THE STANDARD MODEL: IN SEARCH OF SUSY AND OTHER NEW PHYSICS
Sunday, April 14, 11:00 a.m. MDT
The Standard Model theory reliably describes particle interactions, but a complete understanding may require new physics that moves beyond this theory. Bryan Kaufman (Q14.00008) of Northeastern University will present one of the first examples of an explicit string theory-based model that has the potential to be falsified by observational data. The model makes a precise prediction about the relative masses of supersymmetric particles, the researchers say. Kai Yi (B11.00003) of the University of Iowa will discuss an observation of an unexplained structure called Y(4140) that may be a new particle, using data from the CMS detector and the Large Hadron Collider (LHC) in Switzerland. The particle was first seen three years ago by the CDF experiment at the Fermi National Accelerator Laboratory, but its existence was not confirmed until now. A second new particle has also been observed. Santiago Folgueras (X11.00008) of Universidad de Oviedo will discuss his team’s searches for supersymmetry (SUSY) particles in energy regimes that are harder to study, but in which these particles – if they exist – are increasingly likely to be found. The latest results use data collected from the CMS experiment in 2012. And Sungwon Lee (Q2.00001) of Texas Tech University will present an overview on searches for new particles using the latest data from the two big experiments ATLAS and CMS at the Large Hadron Collider (LHC).
Q14.00008 – http://meetings.aps.org/Meeting/APR13/Event/192549
B11.00003 – http://meetings.aps.org/Meeting/APR13/Event/192011
X11.00008 - http://meetings.aps.org/Meeting/APR13/Event/193081
Q2.00001 - http://meetings.aps.org/Meeting/APR13/Event/194958

EXPLODING STARS AND LIFE ON EARTH: EXPLORING THE DISTANT LINKS
Sunday, April 14, 2:00 p.m. MDT
When a massive star runs out of fuel, it may end its life in a violent explosion called a supernova that unleashes a burst of energy and matter across the galaxy.  Shawn Bishop (X8.00002) of Technische Universität München will describe his team’s analysis of preliminary data that suggests the fossils of ancient bacteria contain iron isotopes produced in a supernova explosion whose debris settled over the Earth approximately 2.8 million years ago. And Brian Thomas (X8.00001) of Washburn University will discuss how ionizing radiation from astrophysical events such as supernovae may deplete the Earth’s ozone layer and damage life.
X8.00002 – http://meetings.aps.org/Meeting/APR13/Event/192798
X8.00001 – http://meetings.aps.org/Meeting/APR13/Event/192797

DARK MATTER AND DARK ENERGY
Monday, April 15, 9:00 a.m. MDT
The vast majority of the universe consists of as yet unidentified dark matter and dark energy, and scientists are getting closer to identifying some of the candidates for these elusive particles. Leslie Rosenberg (X2.00002) of University of Washington will review axions, an attractive dark-matter candidate, and the status of the various searches. These experiments are now sensitive enough to either detect the dark matter axions if they exist, or to reject the hypothesis with high confidence, making the next year or two “very interesting for axion researchers,” Rosenberg says. And Alex Drlica-Wagner (G2.00002) of Stanford University will give an overview of the latest results in indirect searches for dark matter with a focus on space-based gamma-ray experiments.
X2.00002 - http://meetings.aps.org/Meeting/APR13/Event/193022
G2.00002 - http://meetings.aps.org/Meeting/APR13/Event/192287

PHYSICS FOR THE PUBLIC
Monday, April 15
11:30 a.m. MDT
Four leading science communicators offer their insights into effective ways to engage the public in scientific discussions. The good astronomer and founder of the Bad Astronomy website, Phil Plait (http://www.badastronomy.com/info/whois.html, R7.00001) will explain why talking about science to the public is more difficult - and more daunting - than actually doing science, and will suggest ways to make the task easier, more productive, and more fun. Author and science blogger Jennifer Ouellette (http://blogs.scientificamerican.com/cocktail-party-physics/, R7.00002) offers tips and tools for broad-based science communication that she developed through writing popular science books and her blog Cocktail Party Physics. Richard Wargo (University of California, San Diego, R7.00003) will describe a non-conventional collaboration between two different creative cultures in the production of the award-winning film “When Things Get Small.” James Kakalios (University of Minnesota), chair of the Physics for the Public session and author of the best-selling book “The Physics of Superheroes,” will be on hand with a selection of physics principles as illustrated in 1960’s comic books.
http://meetings.aps.org/Meeting/APR13/Event/193613
http://meetings.aps.org/Meeting/APR13/Event/192833
http://meetings.aps.org/Meeting/APR13/Event/194956

AMERICAN SCIENCE AND AMERICA’S FUTURE
Monday, April 15
2:00 p.m. MDT
There is an emerging consensus that industry should partner with government, universities, national labs to address issues of science and technology policy, R&D investments, and education.  Jim Gates, a member of President Obama's Council of Advisers on Science and Technology (PCAST) from the University of Maryland will address the new PCAST report addressing the role of the federal government investments in basic research. President of the University of Chicago, Robert Zimmer will tackle the opportunities for university-industry partnerships, and APS President-elect Malcolm Beasley of Stanford University will discuss the U.S. research enterprise as viewed by the American Physical Society
Session – T6 http://meetings.aps.org/Meeting/APR13/SessionIndex2/?SessionEventID=195406

CELEBRATING NIELS BOHR: NEW INSIGHTS ON THE MAN AND THE QUANTUM WORLD HE ENVISIONED
Monday, April 15, 3:30 p.m. MDT
Twentieth-century Danish physicist Niels Bohr’s Nobel-prizing winning description of the structure of the atom sparked great technological advances, but left lingering scientific and philosophical questions. Science historians mark the one hundredth anniversary of the publication of three of Bohr’s most famous papers by taking a fresh look at Bohr’s personality, relationships, and scientific work. John Heilbron (P1.00001) of UC Berkeley and Oxford University will discuss the contents of previously unavailable correspondence between Bohr and his fiancée Margrethe Nørlund. The letters, publically presented for the first time at the APS April meeting, reveal Bohr’s mental ups and downs before and during the creation of his quantum atom model. Alfred Scharff Goldhaber (X7.00001) of Stony Brook University will examine some of the scientific questions raised by Bohr’s model of the atom. And Don Howard of the University of Notre Dame (X7.00003) will discuss how Bohr developed and understood the concept of complementarity, which is one of Bohr's most original contributions to the interpretation of quantum mechanics.
P1.00001 – http://meetings.aps.org/Meeting/APR13/Event/192719
X7.00001 – http://meetings.aps.org/Meeting/APR13/Event/193042
X7.00003 – http://meetings.aps.org/Meeting/APR13/Event/193372


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MORE INFORMATION FOR JOURNALISTS
- General Meeting Information: http://www.aps.org/meetings/april/index.cfm
- Searchable Abstracts: http://meetings.aps.org/Meeting/APR13/APS_epitome

PRESSROOM INFORMATION
A dedicated and staffed pressroom will operate throughout the meeting at the Sheraton Denver Downtown Hotel. Phones, computers, printers, and free wireless Internet access will be available to reporters using the pressroom.
- Location: Sheraton Denver Downtown Hotel, Plaza Court 6 and 7
- Hours: Sat.-Mon., 7:30 a.m. to 5:30 p.m. and Tues., 7:30 a.m. to noon
- Food service: Both breakfast and lunch will be provided Saturday through MOnday. Breakfast only will be served on Tuesday.

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.

Live Webcasts from the 2013 APS March Meeting

Plant mimicry, black holes, and remote-controlled worms are some of the topics to be presented at three live webcasts of news briefings at the 2013 American Physical Society (APS) March Meeting in Baltimore, Md. The three 45-minute webcasts will take place this Thursday, March 21. To register and for more information on the panelists, see below.

What: Media Webcasts on New Research at the APS March Meeting

When: Thursday, March 21, 2013
•        9 a.m. EST - PHYSICS OF NATURE: PLANT MIMICRY AND THE MYSTERY OF THE CRACKLING TREES
•        11 a.m. EST - CREEPY CRAWLIES: FROM REMOTE-CONTROLLED WORMS TO SYNTHETIC CILIA
•        1 p.m. EST - QUANTUM ISSUES: BLACK HOLES, THE REALITY OF THE WAVEFUNCTION, AND WHY SPACE IS 3-D

Registration: To register, please visit http://apswebcasting.com/

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List of Panelists:

Thursday, March 21, 9:00 a.m. EST
PHYSICS OF NATURE: PLANT MIMICRY AND THE MYSTERY OF THE CRACKLING TREES
Panelists:
•        Zi Chen, Washington University in St. Louis, will discuss the mechanics of the Venus flytrap's fast motion and bio-inspired robots whose snapping mechanism could find applications in sensors, artificial muscles, and biomedical devices.
•        Sean Gart, Virginia Tech, will discuss harvesting electric energy from rain using a setup that mimics the process of raindrops hitting leaves.
•        Alexandre Ponomarenko, Grenoble University, will discuss new developments to track down the source of crackling emitted by trees suffering from drought.

Thursday, March 21, 11:00 a.m. EST
CREEPY CRAWLIES: FROM REMOTE-CONTROLLED WORMS TO SYNTHETIC CILIA
Panelists:
•        Askin Kocabas, Harvard University, will present work to manipulate the neural activity of free-moving C. elegans worms using light.
•        Timothy Sanchez, Brandeis University, will discuss synthetic cilia and other biomimetic phenomena that his team has developed using simple, self-organizing biological components (such as microtubules and clusters of motor proteins). The group has also used their techniques to engineer new materials with functions not seen in nature, like flowing liquid crystals and self-propelled emulsion droplets.
•        Daria Monaenkova, Georgia Institute of Technology, will discuss new research that can be used to better understand the behaviors of fire ants, an invasive species in the United States. The work examines the relationship between wetness of soil and ants’ digging strategies for nest construction.
•        Nick Gravish, Georgia Institute of Technology, will dig deeper into fire ants’ nest design strategies with a talk about their underground tunneling tactics, and how tunnel size helps ants keep their footing when the animals are perturbed.

Thursday, March 21, 1:00 p.m. EST
QUANTUM ISSUES: BLACK HOLES, THE REALITY OF THE WAVEFUNCTION, AND WHY SPACE IS 3-D
Panelists:
•        Christoph Adami, Michigan State University, tackles a particularly challenging problem at the intersection of quantum mechanics and relativity: if information is absorbed by a black hole, which then subsequently evaporates, what happens to the information? Adami and colleagues have found what they believe to be a solution to the information paradox posed by black holes, which in turn implies that black holes can act as nearly perfect “quantum copying machines.”
•        Renato Renner, ETH Zurich, has turned to another long-standing puzzle – whether or not the wave-function of quantum mechanics is real or simply a handy calculating tool. Renner’s research addresses deep philosophical issues in physics as well as confirming the effectiveness of quantum-based cryptographic schemes.
•        Markus Mueller, Perimeter Institute for Theoretical Physics, presents a new take on the old question of why space is 3-dimensional, and suggests an answer based on modern quantum information theory.

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MORE INFORMATION FOR JOURNALISTS
•        General Meeting Information: http://www.aps.org/meetings/march/index.cfm
•        Searchable Abstracts: http://meetings.aps.org/Meeting/MAR13/APS_epitome

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.

New 3-Body Orbits Discovered

LY12833 - Predicting the general motion of three celestial bodies, such as planets, or stars, mutually interacting by Newtonian gravity is among the longest standing problems in physics. It was shown by Bruns in 1887 that the three-body problem is not solvable in its most general form, the way the two-body problem is. Over time, three families of particular solutions, realizable under specific conditions, have been discovered, however. All trajectories in these three families share the same geometrical and algebraic symmetries, thus defining a single class.

In this work, we report the discovery of 13 additional distinct families of possible three-body trajectories. Besides three new families belonging to the one previously known class, 10 families belong to three new classes. These three new classes of trajectories represent hitherto unprecedented, and even undreamt of types of planetary motion. While this still leaves the three-body problem unsolvable in general, our findings significantly contribute to the understanding of celestial mechanics and planetary motion.

Historically, the first family was found using only pen-and-paper by the great 18th century mathematicians Leonhard Euler and Joseph Louis Lagrange. Then, in the mid-1970's, the late NASA scientist Roger Broucke and the French astronomer Michel Henon discovered the second family using electronic computers. These computers were among the largest available at the time, but their power was smaller than that of today's mobile phones. The first member of the third family was found by the New Mexico-based computer scientist and physicist Cris Moore in 1993, and is now known as the "figure-8" trajectory. Further members of this family were found between years 2000 and 2005.

Are We Part of a Universe or a Multiverse?

LN13276DR - Can we verify that our Universe is part of a larger Multiverse?  Almost a century ago scientists debated whether the spiral nebulae, what we we now know to be spiral galaxies, were distinct "island universes" of stars apart from our own Milky Way galaxy.  We now understand the Milky Way is but one galaxy in a Universe filled with other galaxies.  Could our entire Universe be encapsulated in but one of many cosmic bubbles in a dynamic Multiverse?  In this paper, we predict detailed and potentially observable signals resulting from a collision in the Multiverse between two cosmic bubbles ---  our Universe and another bubble universe.  Each collision produces a special wave, a cosmic wake, that travels across the Universe from the time of the big bang leaving imprints in the cosmic microwave background (CMB) and large scale distribution of galaxies.  This cosmic wake picks out a special direction on the sky and, we predict, will leave a heretofore unknown highly characteristic "double ring" structure in maps of CMB polarization.  Detection of such a signal would constitute a truly Copernican shift both in fundamental physics and in humanity's view of the what the cosmos is.  Our work goes to the heart of the questions asked by so many about our place in the Universe, but returns quantitative and testable predictions.  Data from next-generation CMB experiments, including the soon-to-be-released data from the ESA/NASA Planck mission, have the potential to uncover the imprints of cosmic bubble collisions. 

Teleportation goes relativistic

LZ12888 - How do motion and gravity affect quantum information tasks? In 2012 a teleportation protocol was successfully performed across 143km between two Canary Islands by A. Zeilinger’s group. In this experiment,  time and positions were determined accurately employing the Global Positioning System (GPS), which is a system of satellites used for time dissemination and navigation. It is well known that GPS takes into account Einstein's theory of relativity to achieve the required precision. However, relativistic effects over the basic resource of the experiment -quantum entanglement- were not considered. Motivated by the success of this kind of tests, space agencies are investing resources for the implementation of space-based quantum communications. At these regimes, relativistic effects can no longer be ignored. In our Letter, we show that relativistic motion and gravity have observable effects in the quantum teleportation protocol. Indeed they can decrease its efficiency; however, we explain how the errors can be corrected. We propose a physical implementation of our relativistic teleportation protocol, which is well within reach of cutting-edge technology using superconducting circuits. The realization of this low-cost tabletop experiment, demonstrating for the first time the effects of relativity on quantum information tasks, will inform expensive space-based programs.

Forming Black Holes From Colliding Particles

LX12835 - This work shows that particles colliding at near the speed of light not only can create black holes, but that they can do so by acting like a gravitational version of a lens.  There was a lot of controversy a few years ago over the possibility that the Large Hadron Collider might create tiny black holes by smashing particles together at high speeds; however the details of how such collisions would unfold remain poorly understood.  In this work, computer simulations of Einstein's theory of gravity are used to study collisions of fluid particles at higher speeds than previously explored.  It is found that black holes can actually form at lower energies than expected, seemingly because the colliding particles act like gravitational lenses, with each particle focusing the energy of the other.  This focusing can concentrate enough energy in a small enough region to warp space and time, creating black holes.

Biogenic crust dynamics on sand dunes

LU13310ER - Sand dunes are often covered by vegetation and biogenic crusts. Despite their significant role in dune stabilization, biogenic crusts have rarely been considered in model studies of dune dynamics.  Using a simple model, we study the existence and stability ranges of different dune-cover states along gradients of rainfall and wind power. Two ranges of alternative stable states are identified: fixed crusted dunes and fixed vegetated dunes at low wind power, and fixed vegetated dunes and active dunes at high wind power. These results suggest a cross-over between two different forms of desertification.

On perpetual motion of the fourth kind

Physical Review D: According to Webster's Dictionary, the perpetual motion is "motion that continues indefinitely without any external source of energy; impossible in practice because of friction". In our paper, contrary to this would-be-obvious statement, we propose an explicit construction of a perpetually moving (rotating) device. Counterintuitively, the proposed device is a solid one-piece object which has no internally moving mechanical parts. Surprisingly, the perpetual rotation of the device is literally driven by zero-point vacuum fluctuations. The device does not produce any work despite the fact that its equilibrium ground state corresponds to a permanent rotation (the device would rotate forever if even it is immersed in a gas). The existence of such device is consistent with all laws of thermodynamics as is proven in the paper explicitly. Intriguingly, the proposed device has an extremely simple construction which is analogous  to the one of certain metamaterials (the latter are used in design of invisibility cloaks, which are also science-fiction-like, but, nevertheless, real physical objects). We point out that the proposed device -- which we call as the perpetuum mobile of the fourth kind -- may possibly be engineered using carbon nanotubes. We stress that the device cannot be used to produce energy from nothing (no existing conservation and/or thermodynamics laws are violated). Summarising, we have proposed a solid one-piece object which rotates forever in its lowest energy state, being driven by zero-point vacuum fluctuations.

Do molecules have intelligence of their own?

LY13069 - Despite the fact that the molecular complementarity and recognition concepts, used to explain the association between macromolecules, which in turn plays an important role in many biological and supramolecular chemistry systems, the underlying molecular mechanism is still not well understood. These concepts suggest that the macromolecules have information of each other, and hence some kind of intelligence, that, on the other hand, we know they do not posses. We show that the union of macromolecules (in a solvent solution), is favored, not by macromolecular recognition, but by the migration of the solvent particles, from their confined position in-between the macromolecules, to the rest of the fluid.

A New Cosmic Measuring Stick: Unusually bright type 1a Supernovae

LY13449 - White dwarfs are formed when stars exhaust their nuclear fuel. In this letter, we establish a new upper mass limit of 2.58 solar mass for white dwarfs. This is remarkably deviated from the famous Chandrasekhar's mass limit of 1.44 solar mass. Our result, unlike Chandrasekhar's, is based on the evolution of magnetic field in white dwarfs. This solves the origin of puzzling, unconventional, over-luminous, type Ia supernovae (explosions of white dwarfs), which must have super-Chandrasekhar mass white dwarfs as progenitors, contrary to those having the conventional Chandrasekhar mass. The characteristic nature of luminosity variation with time of type Ia supernovae allows them to be used as a 'standard' for measuring far away distances (standard candle) and understanding the expansion history of the universe. Applying this idea to conventional type Ia supernovae led to the Nobel Prize in Physics in 2011 for the discovery of the accelerating universe. Our discovery, however, more than 80 years after the proposal of Chandrasekhar mass limit, heralds the onset of a paradigm shift, plausibly leading to establish the unconventional supernovae as new standard candles for cosmic distance measurement.

Collective phenomena in Wikipedia: Cooperation and conflict

LU13814 - The process of conflict resolution in Wikipedia, an iconic, collaboratively edited encyclopedia, is described as the result of the competition between direct interactions among editors and their interactions with a globally shared medium, such as a Wikipedia article. Darwin himself wondered on the origin of the noble virtue of human cooperation being difficult to explain by natural selection. Today, information-communication technology has opened up unprecedented opportunities of solving complex tasks as a collective emergent phenomenon involving the cooperation of many individuals across the world. This has enabled such collaborative projects like open software development or the CERN experiments. While this leads to a higher level of synergy, unavoidably conflicts of diverse opinions are generated, signalled in Wikipedia by an unusually high number of edits in an article. Our model of how Wikipedia works reproduces key stylized features of conflict dynamics observed in real-world Wikipedia articles. For example, with a fixed number of editors forming one 'mainstream' and two opposing 'extremist' groups, consensus in the medium's content is only achieved after a long time and it may not correspond to the initial mainstream view. In the case of a dynamic environment where new editors replace older ones, periods of conflict and consensus can alternate indefinitely, depending on the rate of newcomers and the degree of controversy in the article's topic. The understanding of these mechanisms provided by our model opens the way for the improvement of the conditions for value production in collaborative environments.

Cell shape is the key to understanding blood vessel formation

LX13714E - Blood vessel formation is an important process during development, regeneration and disease. Networks of blood vessels are formed by cells that move around and interact with one another. By computationally modeling this collective behavior of cells we show that long, adhesive cells form networks without any long distance forces and we explain how this happens. In experiments, living cells are seeded on a medium, upon which they elongate and form a network that is similar to the networks formed by our model. This network formation has been attributed to long distance forces, either via chemicals secreted by the cells or mechanical forces conducted by the medium. We now show that long cells form groups of aligned cells. When these groups meet they do not merge but form a branch point and in this manner a network is formed. Earlier studies showed that cell elongation is important in network formation; our work explains how cell elongation helps network formation. Furthermore we show that long distance forces are not necessary, although they may act to stabilize the networks. These new insights can help to interpret experimental results and thus benefit the overall understanding of blood vessel formation.

Optimizing Energy Efficiency with Solid State Thermoelectric Devices

LY13235 - Conservation laws are certainly one of the most elementary and fundamental principles of mechanics. The surprise is that they may play a basic role to solve one of the main problems of future society. Providing a sustainable supply of energy to the world’s population will become a major societal problem for the 21^st century. Thermoelectric phenomena provide a method for heating and cooling,  with no moving parts, possible miniaturization  and absence of emission. They could play a crucial role in a global sustainable energy solution but the  main problem is that in spite of 60 years of research, the efficiency of thermoelectric devices is too low. A breakthrough - allowing increase of efficiency- would have a substantial economic and environmental relevance. In  this letter  we show that total momentum conservation property allows thermoelectric efficiency to reach the ideal Carnot limit.

Engineering a Light Touch

LY13471 - Researchers have found a way to enhance the force of light on matter. Most of the time the momentum of light and the associated forces are too small to notice, but at the nanoscale the effect can be quite large, and researchers have used these forces to dynamically manipulate optical waveguides at the nanoscale. However, these optical forces decay significantly as the distance between the waveguides increases and become too small for all-optical device actuation at larger separation distances.

The new method amplifies the optical forces and thus extends them to larger separations between waveguides by using a novel way to alter the perceived distance between them. This is done with thin layers of engineered structures known as metamaterials, which can manipulate light in ways not seen in conventional materials, extending its influence to greater distances from the surfaces of the waveguide. This work paves the way for the production of optical forces with unprecedented amplitude and eventually the design of mechanical devices activated entirely by light.

Higgs Discovery Points to New Fundamental Constant

LY12930 - The discovery of the Higgs boson at the CERN Large Hadron Collider last year has deep implications for gravitational theories that explain the evolution of our universe. Indeed, the Higgs boson can couple to the gravitational field in a very unique way. This implies the existence of a new fundamental coupling constant in nature, which could be significant, for example, for cosmic inflation. In a paper to appear in the Physical Review Letters, physicists show that the recent discovery at CERN enables us to set the first bound ever on the magnitude of this new parameter of nature. Measuring the coupling of the Higgs boson to the gravitational field with precision ought to have deep implications for the unification of gravity and quantum mechanics and help to fulfill Einstein’s dream.

Contrarian Physics

LR13697E - The allocation of resources is a fundamental issue all species or human beings are facing in their daily life. In order to survive and develop, they must compete against others for sharing such resources by using various strategies. One of the strategies is contrarian behavior. Here we report the existence of a phase transition in a class of well-regulated resource-allocation systems with contrarian behavior by using human experiments, computer simulations, and theoretical analysis. The phase transition allows us to reveal the positive role and the negative role of contrarian behavior. This finding is in contrast to the popular belief that contrarian behavior always has a positive role in resource allocation. This work is of value for various kinds of resource-allocation-related human activities like stock-trading, gambling, travelling, driving, etc.

Centipede Locomotion

LE13747E - Centipedes have many body segments and legs and they generate body undulations during terrestrial locomotion. Centipede locomotion has the characteristic that body undulations are absent at low speeds, but appear at faster speeds; furthermore, their amplitude and wavelength increase with increasing speed. There are conflicting reports regarding whether the muscles along the body axis resist or support these body undulations and the underlying mechanisms responsible for the body undulations remain largely unclear. In the present study, we investigated centipede locomotion dynamics using computer simulation with a body mechanical model and experiment with a robot and then conducted dynamic analysis with a simple model to clarify the mechanism. The results reveal that body undulations in these models occur due to an instability caused by a supercritical Hopf bifurcation. We subsequently compared these results with data obtained using actual centipedes. The model and actual centipedes exhibit similar dynamic properties, despite centipedes being complex, nonlinear dynamic systems. Based on our findings, we propose a possible passive mechanism for body undulations in centipedes, similar to a follower-force or jackknife instability. We also discuss the roles of the muscles along the body axis in generating body undulations in terms of our physical model.

Flowing Grains in Zero-G

LU14260 - Granular materials are ubiquitous in nature and industry. Typical examples are sand on the beach, a drug powder at a pharmaceutical plant, and even the dust and soil covering the surfaces of planets, satellites and small bodies of our Solar System. While flows of granular materials are often studied, a complete set of equations governing these flows is still undiscovered.  In other words, the power to predict granular flows is often faced with large uncertainties despite the existing efforts made to develop sophisticated models.  As an example, little is known about the role of gravity in these flows, as gravity is fixed on Earth, while it is much smaller on celestial bodies such as asteroids, and even on the Moon or Mars.  By using the unique gravitational environment available onboard the Zero-G aircraft, we have performed experiments to investigate the role of gravity in a granular flow. This allows us to explore the behavior of granular material in conditions that become very close to the ones encountered on the surface of much smaller bodies than the Earth.   In normal gravity the flow has two components: the bulk flow that we induce, and a secondary “convective-like” flow. The characteristics of convective-like flows are crucial in industrial applications such as segregation by size, shape, and density, as well as astrophysical questions, such as understanding the behavior of soil on planetary surfaces. We find the secondary flow is suppressed in zero gravity, and enhanced in high gravity. We suggest that gravity tunes the frictional particle-particle and particle-wall interactions that drive the convective-like flow, and present measurements to support this. Such an understanding of the role of gravity is important to interpret the images of granular surfaces sent by space missions visiting other solid bodies of our solar system and to prepare future missions – robotic or manned – which will interact with those surfaces.

How stone monuments deteriorate in the presence of salts

LU13997 - Crystallization in confined spaces, such as pores, is relevant to nearly every field of science. Salts crystallizing within porous materials exert a pressure that contributes to damage, but the quantification of this in-pore pressure is very difficult to achieve. Salt-induced physical weathering has been documented as a substantial damage mechanism in nearly every environment all over the world from pharaoh’s tombs in Egypt, the cathedrals of Europe, decorated caves in China, Mayan pyramids in Mexico and Central America and historic buildings in the United States and England. In this paper, we calculate the solution supersaturation and resulting crystallization pressure and unequivocally identify the precipitating phase in a multi-phase salt system (containing hydrous and anhydrous, metastable and stable phases). These results help to explain why salts, such as Na2SO4 with various hydrated phases are more damaging than single phase salts such as NaCl. We also show that damage associated with meta-stable phase transitions can be suppressed by the use of crystallization promoters. These results point to new ways to prevent salt damage to building materials by bypassing metastable phase formation.

Understanding astrophysical jets with magnetized laser experiments

LX13024 - Objects as diverse as proto-stars, dying-stars and black-holes eject  powerful beams of matter (jets) that are believed to be shaped by magnetic fields. In this letter we show how their formation can be studied in the laboratory by coupling high-power lasers with magnetic fields. In the proposed experiments, an intense laser source irradiates a thin-foil generating a spherically expanding, million-degrees plasma. By imposing a strong magnetic field, this flow can be shaped into an elongated, drop-like bubble which generates a centimetre-long  jet propagating at more than 300 km/s. We speculate that astrophysical jets may be similarly produced from stellar winds expanding in a magnetic field.