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Understanding the fundamental relationship between atomic structure and material properties is the holy grail of the science of materials. Towards this goal we are working to develop a real-time and atomistic understanding of the mechanistic steps taken during the growth and transformation of crystalline materials. To do this we employ a combination of complementary synthetic and characterization approaches, in particular using in situ ultra-high resolution transmission electron microscopy (TEM) to observe key structural transformations in real-time. Our in situ experiments include directly performing nanomaterial synthesis in the TEM, as well as determining the kinetics of structural phase transformations of as-synthesized inorganic nanocrystals. Further, based on an unexpected observation made during one of these in situ measurements, we have developed a new approach to directly synthesize arrays of crystallographically well-defined nanoscale interfaces. Several examples will be presented to illustrate our approach, including: the real-time observation of the solid-state reaction of an individual nanowire; a post-synthetic structural phase transformation within an individual nanorod; and finally, the creation of new nanostructured architectures using liquid metal nanodroplets.

Progress over the past fifteen years in the digitization and analysis of text found in cultural objects (inscriptions, manuscripts, scrolls) has led this past year to a new and astonishing discovery. This talk will tell the story of emerging methods for imaging and analysis culminating in a personal account of the discovery, the people involved, and the technical approaches used.  The digitization of damaged objects supports a new era of collaboration and exploration that has enabled compelling new discoveries and solutions to long-standing problems.

Rydberg atoms were the focus of much of Keith MacAdam's scientific life. Why he found them so fascinating becomes obvious with a brief summary of their properties. Their properties are exaggerated compared to normal atoms, allowing the introduction of novel detection techniques and clear manifestiations of unexpected physical phenomena. Keith was one of the pioneers in the study of Rydberg atoms. His background in radio frequency resonance spectroscopy was the perfect preparation for his initial Rydberg atom work, high resolution microwave spectroscopy, and his measurements are still the best. He is best known, though, for his beautiful work on  collisions of charged particles with Rydberg atoms, particularly charge exchange, the process in which the Rydberg electron hops from its initial ion core to the incoming ion. In spite of the fact that the "modern" Rydberg atom experiments began forty years ago, Rydberg atoms, today at microKelvin temperatures, remain a subject of intense interest.

The 2016 Nobel Prize in Physics was awarded to David Thouless, John Kosterlitz, and Duncan Haldane for research broadly associated with topology in condensed matter physics. In the first half of the talk I  will describe the two-dimensional XY model which undergoes a Berezinskii-Kosterlitz-Thouless phase transition. This transition, unlike many magnetic transitions, lacks spontaneous symmetry-breaking and is driven by the proliferation of topological excitations, vortices. The analog of of this excitation in three dimensions is the "hedgehog" of the Heisenberg magnet. I will explain what this has to do with quantum phase transitions of the two-dimensional Heisenberg antiferromagnet, explicated by Haldane.

I will give a synopsis on Quantum Chromodynamics (QCD) — the fundamental theory of strong interaction, and some of its consequences.
Lattice gauge theory is introduced as a practical way of solving the theory through computer simulation with Monte Carlo methods.
I will show how the proton mass and spin are divided into their quark and glue components in lattice QCD calculations.

Exotic hidden charm pentaquarks were discovered by the LHCb Collaboration in summer 2015. I discuss  two interpretations of these  newly discovered particles. In the QCD inspired hadrocharmonium approach pentaquarks arise naturally as bound states of quarkonia excitations and ordinary baryons. Decay width of the P_c(4450) LHCb pentaquark is explained and calculated, masses and quantum numbers of new pentaquarks are predicted.  In another approach pentaquarks are interpreted as molecular-type loosely bound  states of hadrons with  open charm. Binding in this model is due to the one-pion exchange and interplay of partial waves with different angular momenta.  The hadroquarkonium and molecular approaches  to exotic hadrons are compared and their relative advantages and drawbacks are discussed.

Over the past 25 years, it has been recognized that the light element carbon plays a crucial role in the early chemical enrichment of the Universe.  One fundamental observation is that the frequency of the so-called carbon-enhanced metal-poor (CEMP) stars in the Milky Way increases dramatically with decreasing iron abundance – from 20% of all stars with [Fe/H] < -2.0 to > 80% of stars with [Fe/H] < -4.0.    Recent discoveries of enhanced carbon in damped Lyman alpha systems at high redshift reveal that the abundance patterns observed in this gas are commensurate with a sub-class of the CEMP stars, the so-called CEMP-no stars, which exhibit little or no enhancement of their neutron-capture elements – providing one of the first direct observational linkages between the high-z Universe and presently observed stars in the Galaxy.  I summarize recent progress on our understanding of the production of carbon by first-generation stars, and the powerful constraints that this information provides on Galactic chemical evolution models, the initial mass function in the early Universe, and the nature of first-star nucleosynthesis.

String theory was originally invented to describe hadrons, but soon after Quantum Chromodynamics (QCD) emerged as the precise theory of the strong nuclear force. A quarter century later it was understood that string theory and certain gauge theories akin to QCD are in fact different descriptions of the same physics. I will review the basic relations between gauge theories and strings, and will motivate the exact gauge/string dualities by studying coincident D-branes. I will also discuss applications of these ideas to theories at finite temperature and to gauge theories which exhibit color confinement. The colloquium will also cover some of the recent progress, including the quantum entanglement entropy and three-dimensional conformal field theory.

This is the 2016 Chamblin Colloquium, in memory of our colleague Andrew Chamblin of the University of Louisville.  There will be a special reception beginning at 3pm in CP179.

Neutrinos have come a long way in the human endeavor from their days as a ``desperate remedy.''  Their study now forms the cornerstone of the high energy physics program in the United States.  The U.S. will play host to an international project called DUNE which will explore many of the most important open questions in neutrino physics.  We discovered neutrino mass by doing long-distance quantum phase interferometry with large detectors that were both sensitive scientific instruments and exquisitely beautiful devices.  DUNE will employ an enormous liquid argon time-projection chamber to make the most thorough measurements of neutrino oscillation phenomena ever undertaken.  The large far detector will enable the exploration of a plethora of physical phenomena including nucleon decay and dark matter.  After briefly discussing the history of neutrinos, I will describe the measurements we will make with DUNE and some physics opportunities we will have along the way.