FALL 2021
Physics Department Colloquia and Seminars in 2021
PHYSICS ColloquiumSeptember 16 2021, Thursday, 3:30 pm CSTPhysical Sciences 110Dr. Erin Iski
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PHYSICS ColloquiumSeptember 23 2021, Thursday, 3:30 pm CSTPhysical Sciences 110Dr. Francesco (Frank) NarducciNaval Postgraduate SchoolAssociate Editor: Physical Review A, Physical Review Letters
Towards a T3 atom interferometerIn this talk, I will discuss a novel atom interferometer being developed at the Naval Postgraduate School. I will begin the talk by reviewing the theory of light pulse atom interferometers, concentrating on how the phase of the interferometer scales with the time between the atom optic pulses, T. I will discuss the connection between the Lagrangian and Hamiltonian formulations for the calculation of the phase. Next, I will demonstrate that the T2 scaling is due to a symmetry in the problem and that when the symmetry is broken, a T3 scaling appears (and in our geometry, the phase becomes purely dependent on a T3 term with no T2 terms). I will then turn to a discussion of an experimental implementation involving interferometry on magnetic transitions. The experiment is quite challenging and, although the signature T3 signal has so far eluded us, has provided many interesting features and physics which I will discuss.
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PHYSICS ColloquiumSeptember 30 2021, Thursday, 3:30 pm CSTPhysical Sciences 110Dr. David TománekMichigan State UniversitySaving Humankind from ThirstWhereas water itself is bountiful on Earth, much of it requires treatment to make it suitable for human consumption. Lack of potable water is currently the leading cause of death, ahead of any disease. Recent progress in fabricating nanostructured carbon allotropes may bring a long-awaited paradigm shift in designing membranes that would make efficient desalination of salt water using reverse osmosis and filtration of contaminated water possible. A previously unexplored membrane design [1] based on a unique layered assembly of carbon nanostructures including graphite oxide (GO), buckypaper consisting of carbon nanotubes, and a strong carbon fabric should provide high mechanical strength and thermal stability, resilience to harsh chemical cleaning agents and electrical conductivity, thus addressing major shortcomings of commercial reverse osmosis membranes. Microscopic insight into the critical permeation of water molecules in-between GO layers and across in-layer vacancy defects in graphitic carbon can be obtained using ab initio density functional theory calculations. Results of these computational studies elucidate the reason for selective rejection of solvated Na+ ions in an optimized layered all-carbon membrane. [1] David Tománek and Andrii Kyrylchuk, Designing an All-Carbon Membrane for Water Desalination, Phys. Rev. Applied 12, 024054 (2019). |
PHYSICS ColloquiumOctober 28 2021, Thursday, 3:30 pm CSTVia Zoom (contact Physics Department for link)
Dr. Phillip RyanArgonne National LaboratoryX-ray scattering and Electrical Measurements of Uniaxially Strained Single Crystals: Unconventional Superconductors and Single Phase MultiferroicityIn this presentation I will layout a brief overview of my research at the Advanced Photon Source (APS) with some recent results and describing a vision of what I plan for in the post source upgrade (APS-U) after 2023. The Magnetic Materials Group primarily serves the condensed matter community providing resonant hard x-ray magnetic scattering for single crystal systems, with a particular interest in epitaxial thin films (1). To drive our leading-edge scientific abilities, we continuously develop metrological tools which are made available to the community at large. Here, I will introduce recent developments to drive CMP scientific endeavors forward including low temperature uniaxial strain in a multimodal setup, and dynamic in-situ measurement configuration. Presenting recent results on single crystal unconventional superconducting pnictide systems BaFe2As2 parent compound we demonstrate in-situ uniaxial strain capability with commensurate electrical measurements (2-4). In addition, I will present results from the intriguing, rare earth–titanate, EuTiO3. This material is an excellent platform to explore the interplay between spin, charge, and symmetry within a single system (5-7) and to expand the sample environment control capabilities that now serve a broader range of scientific interests. We try to untangle the magnetoelectric behavior in this single-phase system and in the process demonstrate a ‘giant’ ME cross-field control capability in the rare earth perovskite (5). In bulk form it is both antiferromagnetic and paraelectric. Both anti- and ferro- magnetic interactions are present between different nearest europium neighbors allowing for the notion of magnetic quantum criticality through a combination of doping or strain (8). Fortuitously, like SrTiO3, this system is also considered potentially quantum paraelectric or ‘incipient’ ferroelectric, this conjures the notion of bi-criticality or possibly the emergence of a coupled multiferroic quantum critical point (8).
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PHYSICS ColloquiumNovember 4 2021, Thursday, 3:30 pm CSTPhysical Sciences 110Dr. Alberto Marino University of Oklahoma
Quantum-Enhanced Sensing with Light
There is a significant effort to take advantage of quantum resources, such as entanglement and superposition, to enhance measurements and devices in a way not possible with classical resources. This has led to the development of the emerging area of quantum technologies. Quantum optics will play a significant role in this so called “Second Quantum Revolution” due to the precise control and characterization that can be achieved with light. In this talk I will give an overview on the use of quantum states of light to enhance optical based sensors beyond the classical limit given by the shot noise. I will focus on our work on the interface between entangled twin beams of light and plasmonic sensors and show that a quantum-based sensitivity enhancement can be obtained. I will then describe the fundamental limits to the quantum enhancement that can be achieved. Finally, I will present our most recent work on the implementation of a parallel quantum-enhanced sensing approach.
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