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Colloquium

Unless otherwise noted, the physics colloquia are held in Room 307 of the Science and Engineering Research Facility. Refreshments are served at 3:00 p.m. with the talk following at 3:30.

Please note: since Fall 2017 colloquia are not webcast or recorded. Videos from Spring 2017 colloquia are available here. Earlier semesters are available in the Webcast archives.

Fall 2018 Schedule
Date
Speaker
Title
Host

August 27

Lu Li
University of Michigan

Quantum Oscillations of Electrical Resistivity in an Insulator

Haidong Zhou

September 3

Labor Day Holiday

No Colloquium

 

September 10

Harold Dodds
University of Tennessee

Update on Energy Choices and Consequences

Yuri Kamyshkov

September 17

Peter Yunker
Georgia Tech

Soft Matter Physics of the Evolution of Multicellularity

Max Lavrentovich

September 24

Steven Johnston
University of Tennessee

Probing Competing and Entangled Degrees of Freedom in Correlated Quantum Materials Using Resonant Inelastic X-Ray Scattering

Max Lavrentovich

October 1

Nadia Fomin
University of Tennessee

 

Max Lavrentovich

October 8

Ivan Smalyukh
University of Colorado at Boulder

Colloids and Gels with Order

Max Lavrentovich

October 15

Richard O'Shaughnessy
Rochester Institute of Technology

 

Andrew W. Steiner

October 22

Richard Averitt
UC San Diego

 

Jian Liu

October 29

Axel Hoffmann
Argonne National Laboratory

 

Michael Fitzsimmons

November 5

Charles W. Clark
NIST

 

Geoff Greene

November 12

Brian Beckford
University of Michigan

 

Sowjanya Gollapinni

November 19

Kendall Mahn
Michigan State University

 

Sowjanya Gollapinni

November 26

Valery Nesvizhevsky
ILL

Gravitational Quantum States of Neutrons, Atoms and Anti-atoms

Yuri Kamyshkov

December 3

Dawn Williams
University of Alabama

 

Nadia Fomin


Abstracts
August 27
Lu Li, University of Michigan

Quantum Oscillations of Electrical Resistivity in an Insulator

In metals, orbital motions of conduction electrons are quantized in magnetic fields, which is manifested by quantum oscillations in electrical resistivity. This Landau quantization is generally absent in insulators, in which all the electrons are localized. Here we report a notable exception in an insulator — ytterbium dodecaboride (YbB12). The resistivity of YbB12, despite much larger than that of usual metals, exhibits profound quantum oscillations under intense magnetic field. This unconventional oscillation is shown to arise from the insulating bulk, instead of conducting surface states. The large effective masses indicate strong correlation effects between electrons. Our result is the first discovery of quantum oscillations in the electrical resistivity of a strongly correlated insulator, and will bring crucial insight to the understanding of the ground state in gapped Kondo systems.


September 10
Harold Dodds, University of Tennessee

Update on Energy Choices and Consequences

With the world's population increasing from seven billion currently to approximately nine billion by the year 2040, achieving a healthy lifestyle for all people on earth will depend, in part, on the availability of affordable energy, especially electricity. This work considers the various choices, or options, for producing electricity and the consequences associated with each option. The options are fossil, renewables, and nuclear. The consequences associated with these three options are addressed in five different areas: economics, environmental effects, public health and safety, sustainability, and politics. All options are needed, but some options may be better than others when compared in the five areas. This presentation is a brief summary of the content in a short course entitled “Energy Choices and Consequences”, which was created by the author several years ago and is continually updated.


September 24
Steven Johnston, University of Tennessee

Probing Competing and Entangled Degrees of Freedom in Correlated Quantum Materials Using Resonant Inelastic X-Ray Scattering

Quantum materials hosting strongly correlated electrons are at the forefront of science and technology, with the potentially transformative applications across a diverse set of fields. Despite this potential, obtaining a complete understanding of these materials remains as one of the central unsolved problems of condensed matter physics. The primary difficulty arises from the fact that the electron's potential energy due to the Coulomb interaction is comparable to it kinetic energy. The competition between these two energy scales produces phases of matter that are governed by the collective motion of the particles, and where the electrons can become strongly entangled with the collective excitations associated with competing orders. As such, subtle factors and perturbing influences can often dictate a given material's functional properties. In this context, the challenge in understanding a given compound is to identify and unravel the action of the relevant degrees of freedom and incorporate this information into predictive models. Over the past decade, resonant inelastic x-ray scattering (RIXS) has emerged as a powerful probe of quantum materials, owing to its ability to simultaneously access charge, spin, orbital, and lattice degrees of freedom in a single experiment. In this talk, I will present an overview of RIXS as an experimental probe and discuss several case studies where we have used this technique to understand and disentangle the physics of correlated materials. I will also conclude with a brief perspective on future directions for the method with the development of next-generation light sources.


September 17
Peter Yunker, Georgia Tech

Soft Matter Physics of the Evolution of Multicellularity

The evolution of multicellularity set the stage for an incredible increase in the diversity and complexity of life on Earth. The increase in biological complexity associated with multicellularity required parallel innovation in the mechanical properties of multicellular bodies. Though a cursory review of any multicellular organism provides an appreciation of this intertwining of biological and mechanical complexity, little is known about how such mechanical properties may have evolved. We hypothesize that prior to the evolution of genetically-regulated development, physics played a key role in initiating simple multicellular development. Through a combination of experimental evolution (which allows us to observe the evolution of multicellularity in the lab, as it occurs), and the tools of soft matter (microscopy, mechanical testing, and more), we show that physics likely played a fundamental role in the evolution of complex multicellularity.


October 8
Ivan Smalyukh, University of Colorado at Boulder

Colloids and Gels with Order

Colloids and gels are ubiquitous soft matter systems of our everyday life, ranging from milk to personal care products. I will discuss unexpected self-assembly of highly anisotropic rod-like and disc-like nanoparticles within such soft matter systems [1,2]. This self-assembly allows for the realization of polar fluids predicted by Max Born over a century ago and optically biaxial liquid crystals, often referred to as “Higgs bosons of condensed matter”, that were intensively searched for about five decades. I will show how this fascinating physical behavior of colloids and gels with order may enable applications ranging from thermally super-insulating windows [3] to extraterrestrial habitats.
1. H. Mundoor, S. Park, B. Senyuk, H. Wensink and I. I. Smalyukh. Science 360, 768-771 (2018).
2. Q. Liu, P.J. Ackerman, T. C. Lubensky and I. I. Smalyukh. Proc. Natl. Acad. Sci. U.S.A. 113, 10479–10484 (2016).
3. Q. Liu, A. W. Frazier, X. Zhang, J. De La Cruz, R. Yang, A. Hess and I. I. Smalyukh. Nano Energy 48, 266–274 (2018).


November 26
Valery Nesvizhevsky, ILL

Gravitational Quantum States of Neutrons, Atoms and Anti-atoms

Quantum gravitational spectroscopy with ultracold systems [1] is an emerging field based on recent experimental and theoretical advances. Gravitational spectroscopy profits from exceptional sensitivity due to the extreme weakness of gravitation compared to other fundamental interactions; thus, it provides an access to the precision frontier in particle physics and other domains. Quantum gravitational spectroscopy is its ultimate limit addressing the most fragile and sensitive quantum states of ultracold particles and systems. Ultracold particles – neutrons, atoms, and antiatoms – with sufficiently high phase-space density are the condition for providing observable phenomena with gravitational quantum states. Some of such studies, like those with ultracold neutrons, have become reality [2-4]; others with ultracold atoms [5] and antiatoms [6-8] are in preparation. GRANIT [9] is one of follow-up projects pushing forward the precision and sensitivity of quantum gravitational spectroscopy with ultracold neutrons. Quantum states of antihydrogen atoms in GBAR [6-8] are the key for pushing the precision of measurements of gravitational properties of antimatter. Precision measurements of gravitational quantum states of atoms [5] and neutron whispering-gallery states [10] are promissing methods for improving constraints for fundamental short-range forces [11].
[1] V.V. Nesvizhevsky, and A.Yu. Voronin, Surprising Quantum Bounces (Imperial College Press, London, UK, 2015).
[2] V.V. Nesvizhevsky, H.G. Boerner, A.K. Petukhov et al., Quantum states of neutrons in the Earth’s gravitational field, Nature 415, 297 (2002).
[3] T. Jenke, P. Geltenbort, H. Lemmel et al., Realization of a gravity-resonance-spectroscopy technique, Nature Phys. 7, 468 (2011).
[4] G. Ichikawa, S. Komamiya, Y. Kamiya et al., Observation of the spatial distribution of gravitationally bound quantum states of ultracold neutrons and its derivation using the Wigner function, Phys. Rev. Lett. 112, 071101 (2014).
[5] S. Vasiliev, J. Ahokas, V.V. Nesvizhevsky et al., Gravitational and matter-wave spectroscopy of atomic hydrogen at ultra-low energies, submitted to Hyperfine Interactions (2018).
[6] P. Perez, Y. Sacquin, The GBAR experiment: gravitational behaviour of antihydrogen at rest, Class. Quant. Grav. 29, 184008 (2012).
[7] P. Perez, D. Banerijee, F. Biraben et al., The GBAR antimatter gravity experiment, Hyper. Inter. 233, 21 (2015).
[8] A.Yu. Voronin, P. Froelich, V.V. Nesvizhevsky, Gravitational quantum states of antihydrogen, Phys. Rev. A 83, 032903 (2011).
[9] D. Roulier, F. Vezzu, S. Baessler et al., Status of the GRANIT facility, Adv. High En. Phys. 730437 (2015).
[10] V.V. Nesvizhevsky, A.Yu. Voronin, R. Cubitt et al., Neutron whispering gallery, Nature Phys. 6, 114 (2010).
[11] I. Antoniadis, S. Baessler, V.V. Nesvizhevsky, and G. Pignol, Quantum gravitational spectroscopy, Adv. High En. Phys. 467409 (2015).



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