October 2017 • Vol. 26, No. 9 A PUBLICATION OF THE AMERICAN PHYSICAL SOCIETY ICARUS Arrives Intact Page 4 APS.ORG/APSNEWS 2017 APS Division of Particles and Fields Meeting International News By Eran Moore Rea violated, but only for quarks. It is 2017 Canadian-American-Mexican Conference Three particle physics collabo- possible that CP-violation is the rations announced significant new reason behind the matter-antimatter By Midhat Farooq asymmetry of the universe (that is, experimental results at the 2017 On the morning of August 17th, APS Division of Particles and that despite current big bang pre- dictions, the universe is dominated almost 100 physics graduate stu- Fields meeting from July 31 – dents from Mexico, the United Midhat Farooq August 4 at Fermilab. by matter—humans, trees, stuff— and very little antimatter), but only States, Canada, and Cuba sat in a CP violation with neutrinos: if it is present for leptons as well room together at the first session of 2 sigma as quarks. the 2017 APS Canadian-American- The Tokai to Kamioka (T2K) Particle physicists call a 2-sigma Mexican Graduate Student Physics collaboration shoots a beam of result like T2K’s an observa- Conference (CAM), held in neutrinos across Japan to measure tion—that is, not yet a definitive Washington D.C. Quiet anticipation the ways neutrinos can change discovery. 2-sigma means 95.5% filled the air as the students waited from one type to another during confidence, which might seem for the conference to begin, look- the journey. On Friday, August 4 like enough, but with so much ing around at their international 2017, Chang Kee Jung, former data in large physics experiments, peers with friendly smiles, excited International Co-spokesperson for scientists have mostly agreed that to meet each other and share their the T2K collaboration, presented 5 sigma, or 99.99994% is the research and experiences in the fol- the first experimental indica- “gold standard” to claim an actual lowing days. One might wonder Graduate students from Canada, the U.S., Mexico, and Cuba in Washington D.C. tion of charge-parity violation in discovery. what brought such a diverse group neutrinos. “Today’s result … gives us a of students together. form for physicists from all over place biennially, with the previ- Charge-parity (CP) symmetry reachable target,” Jung said. He Back in 1994, the Canadian the continent to come together for ous two held in Waterloo, Canada is the theory that elementary par- expects in the next several years Association of Physicists (CAP), intellectual discussion, professional (2013) and Oaxaca, Mexico (2015). ticles will act in the same way even that T2K as well as the NOvA APS, and Sociedad Mexicana de development, and the opportunity This past August, CAM2017 when the spatial coordinates are experiment at Fermilab will be able Física (SMF) jointly hosted the to form collaborations. In subse- embraced the theme “Transcending inverted and the sign of the charge to reach 3 sigma, and once DUNE first international North American quent years, CAM was redesigned Boundaries.” they carry is flipped. CP-symmetry physics conference, in Cancun, to serve graduate students exclu- As the conference is largely has previously been proven to be DPF continued on page 6 Mexico, which provided a plat- sively. Since then, it has taken CAM continued on page 4 Forging New Connections Virgo & LIGO: Joint Detection of Gravitational Waves By Abhishek Agarwal and The workshop took place By David Voss science ministers in Turin, Italy, factor of around 20 compared with Samindranath Mitra in Riverhead, Long Island in and a paper describing the detec- On September 27, research- LIGO’s previous detections. August. The scientific program tion has been accepted for publica- Each of these three detec- The editors of Physical Review ers from the Advanced Laser was designed by Subir Sachdev, tion by Physical Review Letters. tors, LIGO’s two in Hanford, Letters, who have a ringside Interferometer Gravitational a condensed matter physicist at The signal, which was observed Washington and Livingston, view of emerging research direc- Wave Observatory (LIGO) and tions, are seeing more papers that Harvard who often collaborates on August 14, 2017, comes from a Louisiana, and Virgo’s in Pisa, Italy, the Advanced Virgo Detector merger of a black hole 30.5 times address condensed matter physics with high energy physicists, and recorded the characteristic “chirp” announced their joint detection the mass of the sun with another with techniques and ideas from John McGreevy, a string theorist at signal of the black holes circling of a gravitational wave signal black hole 25.3 times the mass quantum field and string theories, the University of California at San each other, then speeding up and from the coalescence of two black of the sun. The event occurred often with authors from both com- Diego who now focuses mainly on merging. By comparing the waves’ holes. The observation by three 540 megaparsecs from Earth, or munities. So, when then Editor in condensed matter physics. Around arrival time at each detector, the detectors (two from LIGO and the about 1.8 billion light years away. Chief Pierre Meystre launched the thirty early, midcareer, and senior researchers were able to improve Virgo detector) allows the teams Because the gravitational wave “Physics Next” series of workshops theorists and experimentalists gath- the determination of the source to improve their ability to iden- detection network involves three on topics that are “beginning to ered over three days to discuss direction. Previous detections by tify where in the sky the waves are detectors, the researchers have emerge from the noise,” the over- four broad topics—topological LIGO involved two detectors, coming from. The announcement been able to narrow down the lap of quantum field theory and phases, many-body localization and was made at a meeting of the G7 location of the signal source by a VIRGO continued on page 5 condensed matter physics was a quantum chaos, anomalous trans- logical choice. WORKSHOPS continued on page 4 Research News: Editors’ Choice physics.aps.org Daniel Ucko A Monthly Recap of Papers Selected by the Editors Spinning a tale of graphene approached that of the strongest and spiders artificial carbon fibers and natural Spider silk is known for its high materials (limpet teeth). These new tensile strength and toughness, but Istockphoto results show that a possible way researchers have now found they toward improved silk fibers for a can improve on nature by feeding variety of applications may indeed graphene and carbon nanotubes lie through the spiders’ stomachs. to these tiny weavers. Lepore et Nuclear Fluid Swirls at al. report in 2D Materials (DOI: Record-Breaking Speed 10.1088/2053-1583/aa7cd3) that Observations of gold ion col- Researchers and editors of the Physical Review journals at the second after spraying water contain- lisions reveal that the post-crash Physics Next workshop Carbon diet for better silk ing graphene flakes or carbon nuclear matter rotates faster than nanotubes into a corner of a box ter, the researchers measured the any other recorded fluid. This of spiders, and waiting until the silk that was successfully obtained, strong swirling occurs in a hot animals had ingested the mixture, and they used Raman spectroscopy mixture of quarks and gluons, the resulting silk was markedly to characterize the molecular struc- called the quark-gluon plasma. stronger and tougher. The team ture of the unmodified and modi- Created in heavy ion collisions, tested the carbon diet on 21 spi- fied silk samples. On average, the this plasma was presumably the ders of three different species (alas, team notes, the strength and tough- dominant form of matter during 6 died before their silk could be ness of the silk from nanotube-fed obtained). Using a nanotensile tes- spiders surpassed natural silk and RESEARCH continued on page 6 2 • October 2017 Spotlight on Development This Month in Physics History Shining the Spotlight on You October 1910: First infrared photographs published Dear APS member, These above programs have As the end of 2017 fast been recognized both nationally nfrared photography is an invaluable workhorse between runs when the Frenchman wasn’t look- approaches, we wish to thank you and internationally for their value Itool across many different scientific fields and ing, and when Blondlot still claimed to observe for your continued involvement and to the physics community in help- practical applications, as well as a popular hobby N-rays on the second run, Wood concluded he support. We know that at this time ing inspire and prepare the next among professional and amateur photographers. was deluding himself, and wrote a letter to Nature of the year you have many choices generation of physicists. And we owe its existence—as well as that of ultra- debunking the claim. violet photography—to an enterprising American The year before, in 1903, Wood invented an of worthy, charitable causes and Here is what some of you have related year-end campaigns, and we physicist and inventor named Robert Williams ultraviolet filter for photography, which he made said about the reasons for giving are most grateful for your willing- Wood, best known in scientific circles for his from nitroso-dimethyl-aniline, combined with a to APS. ness to keep APS in mind. research on optics and spectroscopy. small amount of a dye called uranine. This made Thanks in part to your finan- “APS programs make a big dif- Infrared radiation was discovered in 1800 by the filter block visible light but transmit ultravio- cial generosity, APS has built ference to students and researchers; Sir Frederick William Herschel, best known for let, and he used it to take the first photographs of an impressive track record of I know my donation is effectively building telescopes and ultraviolet fluorescence.