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Events on Thursday, January 19th, 2017

R. G. Herb Condensed Matter Seminar
Physics / Electrical and Computer Engineering
Physics after the lab and the desk: Your work in PRL
Time: 10:00 am
Place: 5310 Chamberlin
Speaker: Samindranath Mitra , Editor in Physical Review Letters
Abstract: Physics research takes place mostly at your desk, at the keyboard, in the lab. You communicate results through posters, talks, and papers -- leading to, hopefully, wide dissemination and recognition. The sequence entails interacting with journal editors, referees, conference chairs, journalists, and so on. I will focus on this post-research collaborative process in physics, primarily through the lens that is Physical Review Letters.<br>
Host: Mark Eriksson and Irena Knezevic
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Atomic Physics Seminar
Quantum entanglement for precision sensing with atoms and light
Time: 12:00 pm
Place: 5310 Chamberlin Hall
Speaker: Onur Hosten, stanford
Abstract: In the last decades, advances in the level of precision in controlling atomic and optical systems opened up the low-energy precision frontier to fundamental physics tests in addition to yielding new applied sensing technologies. In this talk I will focus on our experiments with cold atoms highlighting some of the most recent developments in the prospect of using quantum entanglement to further improve the precision of atomic and optical sensors.
I will describe the generation of 20dB spin-squeezed states of half a million 87Rb atoms inside of an optical cavity. From a practical point of view, the generated states enable up to a 100-fold reduction in required averaging times or atom numbers to achieve a given precision. I will explain the implementation of an atomic clock operating 10 dB beyond the standard quantum limit as well as the investigations of entanglement and Bell correlations in this system. I will then describe the demonstration of a new concept we call quantum phase magnification which utilizes optical cavity-aided interactions between atoms to magnify signals to-be-measured. This technique eliminates the need for low noise detection to achieve phase sensitivities beyond the standard quantum limit. I will conclude with future visions.
Host: Thad Walker
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NPAC (Nuclear/Particle/Astro/Cosmo) Forum
Cosmic-ray proton measurements with the Fermi-LAT
Time: 2:30 pm
Place: 5280 Chamberlin Hall
Speaker: David Green, University of Maryland/Goddard
Abstract: The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope has continuously observed the gamma-ray sky since June 2008.
Cosmic-ray protons represent the majority of events downloaded from the Fermi-LAT, which are removed from the gamma-ray dataset. Our sample is comprised of over 1 billion cosmic-ray protons to TeV energies. We present the measurement of the cosmic-ray proton spectrum between 54 GeV and 9.5 TeV using 7 years of Pass 8 flight data from the Fermi-LAT. We developed a dedicated proton event selection with an acceptance of 0.25 m^2 sr. Our analysis yields a large dataset with low statistical uncertainty and low residual contamination for a spectral measurement. The systematic errors associated with the acceptance, energy measurement, GEANT4 Monte-Carlo simulations are an order of magnitude larger than the statistical uncertainty. The event selection and spectral measurement of the proton analysis create the opportunity for additional proton analyses with the Fermi-LAT, such as a dedicated proton anisotropy search.
Host: Stefan Westerhoff
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