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November 2016 • Vol. 25, No. 10 Nobel Chemistry Committee Cites A PUBLICATION OF THE AMERICAN PHYSICAL SOCIETY Feynman’s 1959 APS Talk APS.ORG/APSNEWS Page 4 From Quarks to Cosmos in the Nation’s 2016 Nobel Prize in Physics Capital: 2017 APS April Meeting By Rachel Gaal electronics and superconductors. By Rachel Gaal session. John Holdren, Director This year’s Nobel Prize for phys- The collaboration of Kosterlitz and Calling all physicists — it’s of the U.S. Office of Science and ics was awarded on October 4, with Thouless in the 1970s sought to chal- time to get ready to travel to Technology Policy, and Cherry one half to David J. Thouless of the lenge the theory that ordered phases Washington Univ.of Washington, D.C! The 2017 APS Murray, Director of the Office University of Washington, Seattle, and phase transitions could not occur April Meeting will be held January of Science, U.S. Department of and the other half to both F. Duncan in thin layers. With topology as a tool, 28 - 31, 2017, at the Marriott Energy, will discuss the changing they demonstrated that superfluidity role of science within policymak- M. Haldane of Princeton University David J. Thouless Wardman Park Hotel. The April and J. Michael Kosterlitz of Brown can indeed exist in a thin layer as a Meeting (held next year in January ing and their roles as physicists University. The committee’s official result of a transition between topologi- to avoid the exploding cost of hotel in the government. Rush Holt Jr., citation reads, “For theoretical discov- cally distinct phases of matter. Now rooms during the spring cherry CEO of the American Association eries of topological phase transitions recognized as a fundamental mecha- blossom viewing season) will host for the Advancement of Science and topological phases of matter.” nism in condensed matter physics, exciting talks about quirky quarks, (AAAS) will discuss the impor- Princeton University In the early 1970s and 1980s, these topological phases have been identified the vast cosmos, and much in tance of promoting science among three physicists explained phenomena in 1D materials, like chains of atoms, between. policymakers. Congressman Bill thin layers of matter (2D), and some Foster, representing the 11th in quantum states of matter, such as F. Duncan M. Haldane Expecting over 1,500 attend- the quantum Hall effect and superfluid 3D materials. ees, the organizers will welcome District of Illinois, will also join phase transitions, using the mathemati- The applications of topology 130 invited speakers and offer in the session to discuss his experi- cal concepts of topology. They cor- extended into Thouless’s and Haldane’s three plenary sessions that cover ence as a “physicist on the hill” and rectly predicted transitions in these work in the 1980s, when they employed topics of particle physics, astro- as a U.S. representative. these concepts to unravel the magnetic The Kavli Foundation spe- unusual phases of matter. Moreover, Brown University physics, nuclear physics, and their success has sparked an array of properties of low-dimensional materi- gravitational physics. cial plenary session, scheduled research with topological materials, als. Haldane studied magnetic atomic Government and political for Monday, will feature talks which could be used in future quantum chains, and discovered that their topo- figures will speak on the theme from Barbara Jacak of Lawrence Berkeley National Laboratory computers or in new generations of NOBEL continued on page 3 J. Michael Kosterlitz of “Science Policy in the 21st Century” at Saturday’s plenary MEETING continued on page 3 Q&A with Sabine Hossenfelder: Consultant for Armchair Physicists Research News: Editors’ Choice physics.aps.org By Sophia Chen A Monthly Recap of Papers Selected by the Editors When funding for her quantum gravity research started to look Atomic Force Microscopy Backreaction spotty, Sabine Hossenfelder came Maps Vector Field in 2D up with an unusual solution to Two independent groups have developed atomic force micros- pay the bills. First, Hossenfelder, Nature Nanotech. a research fellow at the Frankfurt copy (AFM) schemes that can Institute for Advanced Studies in measure vectorial force fields in Germany and well-known physics two dimensions. AFM can image blogger, wondered, “What is all the surface of a sample with this knowledge in quantum gravity atomic resolution by recording good for?” the force exerted by a sample on And then she thought about all the tip of an oscillating cantilever. those armchair physicists out there, Conventional setups, in which the the ones who cook up their own cantilever motion is limited to one theories of everything and pro- Sabine Hossenfelder dimension, probe only the projec- tion of the force along a specific Researchers have successfully mapped the vector force from a surface in claim in Internet comments that I can sort of relate to your two dimensions by using a nanowire as the probe in an atomic force micro- they can prove Einstein wrong. She experience. When I was study- direction. Mercier de Lépinay et scope. posted an offer to act as a phys- ing physics in grad school, we’d al. and Rossi et al. replaced the the measurement of the directional the Fermi-Hubbard model within a ics consultant on Facebook and get emails from random people cantilever tip with a nanowire, nature of Casimir forces. controllable platform. Three sepa- on her blog: for 50 U.S. Dollars, which follows the surface forces pushing their pet theories on us. Atoms Mimic Antiferromagnetism rate groups—Parsons et al., Boll et she would spend 20 minutes on But we’d delete them and laugh it like the needle of a record player. New experiments with cold al., and Cheuk et al.—have placed Skype answering your questions off. Why’d you decide to engage Both setups, which are described atoms demonstrate magnetic cor- cold atoms in optical lattices and and setting you straight on your with them? in Nature Nanotechnology relations that could help explain utilized site-resolved imaging to pet theory. If you were open to it, I admire their drive a lot. These (doi:10.1038/nnano.2016.193, high-temperature superconduc- measure the number of atoms, as she’d also suggest concepts to learn people have spent a lot of time on 10.1038/nnano.2016.189), use tivity. The observed correlations well as their spin, at each site in and papers to read. The clients have their theories, and they really want optomechanical readout tech- support a condensed-matter model the lattice. The results, reported in rolled in: Since starting the ser- to understand [the physics] and niques, in which laser light moni- that assumes electrons in a crys- the journal Science (doi: 10.1126/ vice a year ago, Hossenfelder has contribute. They love the science. tors displacements of the nanowire. science.aag1430, 10.1126/sci- tal hop between lattice sites, while expanded the operation to include They’re not people I like to ignore. The two-dimensional force field ence.aag1635, 10.1126/science. also avoiding each other because five more physicists. Has anyone come up with any- of the sample surface can then be aag3349), showed that neighboring of repulsive interactions. When In addition to quantum grav- thing publishable? extracted by measuring the effect of atoms typically had opposite spins, the electron density is at a certain ity research and this consult- Not yet. I’ve only offered this the field on two orthogonal oscil- as expected for antiferromagnetic level, this so-called Fermi-Hubbard ing service, Hossenfelder writes service for a little over a year, and lation modes of the wire. Mercier ordering. The experiments also model predicts the material will prolifically about physics in her you know, nobody can immediately de Lépinay et al. used the setup to showed evidence of longer-range exhibit antiferromagnetic ordering, blog for non-technical audiences, publish when they first start study- map the force field produced by a correlations (between more distant in which magnetic moments — or Backreaction, and in publications ing physics. But before this service sharp tip, while Rossi et al. imaged neighbors), which could play a role spins — of the electrons align in like Forbes and Aeon. She spoke existed, people were already asking a patterned semiconductor surface. in generating high-temperature an alternating (up/down) pattern. with APS News last month about me about their theories, and one A vectorial AFM will be useful in a superconductivity in antiferromag- her experiences counseling phys- Testing this prediction is difficult in person actually did publish a paper. wide range of applications, includ- netic materials. ics enthusiasts. This interview has ing the characterization of the solids, but cold atoms offer a way been edited for length and clarity. Q&A continued on page 5 anisotropy of chemical bonds and to simulate the basic elements of RESEARCH continued on page 5 2 • November 2016 Inside the Beltway This Month in Physics History An Election to Remember: Sex, Lies, and Videotape By Michael S. Lubell, APS Director of Public Affairs November 7, 1940: Collapse of the Tacoma Narrows Bridge If you’re sick of seeing and based arguments have become a hearing the presidential candidates vanishing expectation. hen the Tacoma Narrows Bridge over Puget duke it out over their indiscretions The post-debate TV analysis WSound in the state of Washington famously and worse, you’ve got plenty of used to revolve around spin room collapsed on November 7, 1940, it was captured on company. But as a physicist, I am dissection. But this year, it has film for posterity. The footage became the basis for even more disturbed by the way become a gotcha forum for under- a textbook example of resonance, which is a stan- evidence has taken a back seat to scoring how the candidates — par- dard topic in high school physics.