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Events on Thursday, February 20th, 2020

R. G. Herb Condensed Matter Seminar
Entanglement and metrology in an array of alkaline-earth atoms
Time: 10:00 am
Place: 5310 Chamberlin Hall
Speaker: Jacob P. Covey, Caltech
Abstract: Quantum entanglement is the central resource in quantum information science applications including metrology, computation, and communication. A defect-free array of isolated, neutral particles with long-range, state-dependent interactions is an attractive architecture for scalable entanglement generation. In this talk, I will describe two platforms that offer long-range interactions: polar molecules, and atoms in highly-excited Rydberg states. I will focus on alkaline-earth atoms (AEAs), which also possess ultra-narrow ‘clock’ transitions for precision metrology. I will describe the techniques we pioneered for cooling and imaging single AEAs in optical tweezer arrays for the first time [1,2], as well as a new platform for metrology based on single-atom readout in an atomic array clock [3]. Further, I will discuss recent observations of high-fidelity control, detection, and entanglement using Rydberg states [4]. I will close with an outlook of future research directions.

[1] A. Cooper, JPC, et al., “Alkaline-Earth Atoms in Optical Tweezers”, Phys. Rev. X 8, 041055 (2018).

[2] JPC, et al., “2000-Times Repeated Imaging of Strontium Atoms in Clock-Magic Tweezer Arrays”, Phys. Rev. Lett. 122, 173201 (2019).

[3] I. S. Madjarov, …, JPC, et al., “An Atomic-Array Optical Clock with Single-Atom Readout”, Phys. Rev. X 9, 041052 (2019).

[4] I. S. Madjarov*, JPC*, et al., “High-Fidelity Control, Detection, and Entanglement of Alkaline-Earth Rydberg Atoms”, arXiv:2001.04455 (2020).
Host: Saffman
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Cosmology Journal Club
Time: 12:00 pm - 1:00 pm
Place: 5242 Chamberlin Hall
Abstract: We discuss papers from related to cosmology each week. All are welcome and feel free to bring your lunch. If there is a paper you would like to present, or have questions or comments, please email Ross Cawthon ( and Santanu Das (
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NPAC (Nuclear/Particle/Astro/Cosmo) Forum
The TeV-PeV Diffuse Neutrino Background
Time: 2:00 pm
Place: 4274 Chamberlin Hall
Speaker: Nathan Whitehorn, UCLA
Abstract: In 2014, the IceCube Neutrino Observatory announced the discovery of an isotropic, isoflavor diffuse background of neutrinos with energies extending from 10 TeV to well above 1 PeV, presumably associated with the unknown emitters of high-energy cosmic rays. Six years later, the origin of these neutrinos remains a mystery. The background is, within measurement uncertainties, uncorrelated with any of the standard catalog of high-energy sources (our galaxy, blazars, gamma-ray bursts, etc.), challenging explanations involving simple models. The 2017 detection of neutrino emission from the distant blazar TXS 0506+056 has only deepened this mystery. In this talk, I will discuss the current state of our knowledge of the high-energy neutrino sky and outline the next steps in the experimental program to resolve these questions.
Host: Albrecht Karle
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Theory Seminar (High Energy/Cosmology)
Future cosmology with CMB lensing and galaxy clustering
Time: 4:00 pm
Place: 5280 Chamberlin
Speaker: Marcel Schmittfull, Institute for Advanced Study
Abstract: Next-generation Cosmic Microwave Background experiments such as the Simons Observatory, CMB-S4 and PICO aim to measure gravitational lensing of the Cosmic Microwave Background an order of magnitude better than current experiments. The lensing signal will be highly correlated with measurements of galaxy clustering from next-generation galaxy surveys such as LSST. This will help us understand whether cosmic inflation was driven by a single field or by multiple fields. It will also allow us to accurately measure the growth of structure as a function of time, which is a powerful probe of dark energy and the sum of neutrino masses. I will discuss the prospects for this, as well as recent progress on the theoretical modeling of galaxy clustering, which is key to realize the full potential of these anticipated datasets.
Host: Dan Chung
Presentation: Madison_talk_for_pdf.pdf
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