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April 21, 2017

Quantum Technologies for Optical Communication

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Date: Thursday, April 27th, 2017

Speaker: Francisco Elohim Becerra, University of New Mexico

Abstract:

Quantum information science can enable communication technologies with capabilities surpassing those of current technologies. For example, by harnessing the quantum properties of light or single-photon detection, it is possible to devise measurements achieving sensitivities beyond the ultimate sensitivities of current coherent communication technologies. Furthermore, by using entangled pairs of photons it is possible to establish absolute secure communication via quantum key distribution, where security is guaranteed by the quantum properties of these photons. However, the ever-increasing need for higher transmission rates in communication will require future quantum technologies to be able to enhance information transfer for applications in classical or quantum communication, while extending communication links over long distances. Here, we describe our current work on quantum measurements with high sensitivity for states of light working as information carriers, and atom-photon interfaces based on atomic ensembles and single photons carrying information encoded in their spatial degrees of freedom. These interfaces can in principle allow for increasing information transfer in secure communication over long distances.

Host: Brian Smith

Time: 4:00-5:00pm
Location:  100 Willamette Hall

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April 14, 2017

The International Race For A Quantum Computer

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Date: Thursday, April 20th, 2017

Speaker:  Stephanie Simmons, Simon Fraser University

Abstract:

Silicon transistors, the essential building block of most modern electronic devices, cannot shrink much further without being rendered inoperable by quantum mechanics. This classical-quantum threshold in fact presents a tremendous opportunity: if we harness quantum mechanics, rather than attempt to avoid it, we could build a quantum computer. Quantum computers will open up a world of opportunities — they could accomplish certain computational tasks exponentially faster which would otherwise be forever impractical. During this lecture, Dr. Simmons will discuss various quantum computing approaches, how quantum technologies will change our lives in a very fundamental way, and provide a snapshot of the accelerating worldwide race to build a prototype.

Host: Brian Smith

Time: 4:00-5:00pm
Location:  100 Willamette Hall

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April 7, 2017

Communications with a Twist

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Date: Thursday, April 13th, 2017

Speaker:  Martin Lavery, Royal Academy of Engineering Research Fellow, School of Engineering, University of Glasgow

Abstract:
I will discuss my current findings in the development of point-to-point free-space links that employ spatial division multiplexing as a method to dramatically increase the available data rates and security in last-mile networks. The talk will give a brief overview of the state-of-the-art developments that are shaping the research field. The focus will be on my studies into the 1.6km propagation of optical beams that carry Orbital Angular Momentum, along with studies into a shorter link in an underwater environment. I will also discuss the use of plane-wave states as an alternative to Orbital Angular Momentum within a point-to-point free-space link.

Bio:
Martin completed his Ph.D at the University of Glasgow under supervision of Prof. Miles J. Padgett. After his Ph.D. he was awarded an EPRSC Doctoral Prize Fellowship to support his post doctoral research, and in 2013 he was Awarded the Scopus Young Research Award UK in the Physical Sciences. Martin is currently the holder of Royal Academy of Engineering Research Fellowship and is leading the Structured Photonics Research Group at the University of Glasgow.

Host: Benjamin McMorran

Time: 4:00-5:00pm
Location:  100 Willamette Hall

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March 14, 2017

Probing Sub-Critical and Super-Critical Impurities in Graphene

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Date: Thursday, April 6th, 2017

Speaker: Victor Watson Brar, University of Wisconsin – Madison

Abstract:

Graphene, an atomically thin sheet of carbon atoms, is a two dimensional semi-metal in which the electrons behave as massless Fermions. Because it is extremely thin and has a low carrier density, the local electronic structure of graphene can be strongly modified by impurities found either in the nearby environment, or introduced via intentional doping. This talk will discuss several impurity related phenomena that are observed in graphene and how they can modify the macroscopic properties that are observed in graphene devices. By using a scanning tunneling microscope to construct, atom-by-atom, different species of impurities, we will show that phenomena can be realized that are analogous to as-of-yet unobserved high energy physics effects. Namely, it will be shown that ‘super-critical’ impurities can be created in graphene, which demonstrate how electrons and positrons would behave around a nuclear core with Z > 173, where the binding energy of the electron exceeds 2m­ec2.

Host: Benjamín Alemán

Time: 4:00-5:00pm
Location:  100 Willamette Hall

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March 3, 2017

Exploring the Gamma Ray Universe: Fermi-LAT then, now, and the future

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Date: Thursday, March 9th, 2017

Speaker:  Bill Atwood, UC Santa Cruz

Abstract:

The Gamma ray Large Area Space Telescope (GLAST) project began in 1992, a year after the launch of EGRET onboard the CGRO spacecraft.   Capitalizing on advances in particle detector technology, the GLAST project developed an observatory that extends the discovery space of EGRET by over an order of magnitude.   After its launch in 2008, GLAST was renamed Fermi-LAT and has performed an all-sky survey of the gamma ray universe ever since.   This talk will present details of how the instrument was designed and how the design choices contributed to the success of the mission.   The presentation will include highlights from the first 8+ years of the Fermi-LAT as well as its science potential going forward.

Host: Jim Brau

Time: 4:00-5:00pm
Location:  100 Willamette Hall

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February 28, 2017

The First Four Months of Gravitational Wave Astronomy

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Date: Thursday, March 2nd, 2017

Speaker:  Ben Farr, University of Chicago

Abstract:

On September 14, 2015 LIGO made the first direct detection of gravitational waves, marking the true beginning of gravitational wave astronomy. I will present the methods behind the detection and characterization of LIGO’s binary black hole mergers, and what they have taught us about compact binaries thus far. I will focus in particular on the important astrophysical ramifications of these initial detections, and what we can be expected to learn in the near future from gravitational-wave astronomy.

Host: Jim Brau

Time: 4:00-5:00pm
Location:  100 Willamette Hall

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February 24, 2017

Silicon, Straws, and SUSY:Searches for Supersymmetry featuring the ATLAS Inner Detector

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Date: MONDAY, February 27th, 2017

Speaker:  Laura Jeanty, Lawrence BerkeleyNational Laboratory, Berkeley, CA

Abstract:

The keystone of the standard model of particle physics, the Higgs Boson, was discovered during the first run of the Large Hadron Collider (LHC). The LHC is halfway through its second run, with higher energy and higher intensity collisions providing a dataset ripe for discovery of physics beyond the standard model. Supersymmetry remains a promising theory for new physics accessible at the LHC. The inner tracking detector plays a crucial role in many searches for supersymmetry on the ATLAS experiment. In this talk, I will discuss the current status and outlook of supersymmetry searches by ATLAS, with a focus on the different ways in which the inner detector extends our sensitivity to new particles.

Host: Ray Frey

Time: 4:00-5:00pm
Location: 123 PACIFIC HALL

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February 21, 2017

From Gravitons to Electrons: the Discovery of GW151226

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Date: Thursday, February 23rd, 2017

Speaker:  Sarah Caudill, University of Wisconsin-Milwaukee

Abstract:

LIGO’s detection of the first gravitational wave signal, GW150914, ushered in the era of gravitational wave astronomy with quite a bang, giving us a measurement of the heaviest stellar mass black holes to date and providing new stringent tests of general relativity. However, the detection of the second signal, GW151226, on December 26, 2015 was arguably just as exciting. I will describe the technology that allowed this signal to be detected just 70 seconds after arrival. Additionally, GW151226 spent nearly 55 cycles in LIGO’s sensitive band compared to only 10 cycles for GW150914. I will discuss the precise measurements of the compact binary parameters that were afforded by this longer signal. Finally, I will describe how these two gravitational wave detections inform our predictions for more discoveries in the near future.

Host: Jim Brau

Time: 4:00-5:00pm
Location: 100 Willamette Hall

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February 17, 2017

Measuring Storms in Space-Time: Astronomy with Gravitational Radiation

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Date: MONDAY, February 20th, 2017

Speaker:  Robert Ward, Department of Quantum Science, Australian National University

Abstract:

On September 14, 2015, the LIGO detectors recorded the first direct observation by humankind of gravitational waves — space-time distortions generated by objects with extreme gravity. These waves propagate over astrophysical distances and can be detected by the modulation imposed on the optical path of a suspended mirror laser interferometer. We now have a new form of radiation with which to study the Universe. The level of displacement sensitivity which enabled the first detections, less than 1 part in 10,000 of a proton diameter, mandates not only significant isolation from environmental noise, but also a readout scheme capable of measurement at this level. I will discuss gravitational waves and the technology developed to detect them, including the optical metrology techniques that enable the Advanced LIGO detectors to reach their extraordinary sensitivity and how we extract the signals necessary to control the interferometer. I will describe what we have observed so far and what we hope to learn about the universe with this new astronomical messenger

Host: Jim Brau

Time: 4:00-5:00pm
Location: 123 PACIFIC HALL

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February 14, 2017

Science on the Edge: Critical Phenomena in Granular Systems

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Date: Thursday, February 16th, 2017

Speaker:  Susan Lehman, Claire Booth Luce Associate Professor of Physics at The College of Wooster in Wooster, Ohio

Abstract:   A granular system behaves in some ways like a liquid with an ability to flow, and in some ways like a solid with a stable fixed structure if undisturbed. A tiny stimulus to the pile most often results in only a small response, but the same small stimulus can also create an unpredictable and catastrophic collapse of the pile. These collapses occur both in natural settings, with hazards such as landslides and snow avalanches, and in industrial situations, where granular materials like sand or agricultural grains need to flow freely. We use a simple experimental system – a 3D conical pile of uniform beads – in order to model these real-world physical systems. We investigate the dynamic response of the pile by recording avalanches from the pile over the course of tens of thousands of bead drops. The resulting behavior is well-characterized by universal power laws and scaling functions, relating this work to the broader study of critical systems.
All of these results were obtained at The College of Wooster, a liberal arts college with a particular focus on mentored undergraduate research. As part of the talk, I will discuss how work at a liberal arts college differs from work at a large research university, and suggest ways to prepare for alternative academic careers.

Host: Ray Frey

Time: 4:00-5:00pm
Location: 100 Willamette Hall

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