Please join us Monday, July 14 for a talk from Cornell group visitor Heleen Mulder. Heleen is a PhD student working on theoretical particle physics with Jordy de Vries at Nikhef in Amsterdam and a member of the NLeEDM collaboration.

Abstract: The experimental search for CP violation in paramagnetic atomic and molecular systems has made impressive progress in recent years. This has led to strong upper limits on the electron electric dipole moment. Interestingly, the same measurements can be used to constrain hadronic sources of CP violation, through CP-violating interactions between the electrons and the nucleus. In this talk, I will focus on one specific source of hadronic CP violation: the QCD theta term. I will sketch calculations of the relevant CP-violating electron-nucleus interactions, carried out in an effective field theory formalism. Based on this work, we arrive at a novel upper bound on the theta parameter. While currently two orders of magnitude less stringent than the upper bound from the neutron EDM, further experimental improvements on the paramagnetic EDM side could soon make this bound competitive. If and when EDM experiments start yielding non-zero results, these independent bounds will be crucial to disentangle the possible underlying CP-violating sources. Aside from the QCD theta term, the methods presented in this talk can also be used to determine contributions from other hadronic sources of CP violation to paramagnetic EDMs.

Abstract: For decades, scientists have pursued a bold goal: creating a laser that works not just with visible light but with powerful X-rays. Conventional X-ray sources, essential in medicine, security, and technology, are based on principles dating back to Röntgen’s discovery in 1895, essentially a brighter, more advanced X-ray light bulb. But just as lasers revolutionized the way we harness visible light, an X-ray laser would unlock extraordinary new capabilities in science and technology. The challenge? Generating such intense, precise X-ray beams once required enormous machines and extreme conditions. Remarkably, advances in quantum physics have changed this. Researchers can now create compact, tabletop X-ray lasers, a breakthrough opening the door to next-generation microscopes that reveal the nano-world with stunning clarity and in real time. This lecture will explore how quantum science made this possible and what it means for the future of imaging, materials, and more.

Take a mid-morning break! Come hang out with your fellow staff for an easygoing hour of coffee, conversation, and sunshine on the H-bar balcony!

Bring your favorite drink — whether it’s something from home, a warm cup from the JILA lounge tea station, or a pick-me-up from a nearby coffee shop*. No agenda, no pressure — just a chance to relax, recharge, and connect.

Organized by staff, for staff, and everyone’s welcome. We hope you’ll drop in!

Want to work safely and confidently with lasers?  We've got you covered. Join us for an engaging and informative in-person Laser Safety Training session led by none other than Josh Hadler, NIST's Laser Safety Officer.

Mark your calendars for Tuesday, July 22nd, from 9:00am to 12:00pm in the JILA Auditorium. This is a fantastic opportunity to learn best practices and ensure your safety while working with lasers.  Whether you're a seasoned pro or just starting out, this course is invaluable.

This training is required for anyone working with lasers, but even if you've taken it before, consider this a valuable refresher. Josh will be on hand to share his expertise and will even have a variety of laser safety goggles for you to try on. This hands-on experience will help you find the perfect fit for your needs.

No need to pre-register - just show up and sign the attendance sheet when you arrive. I will take care of adding the training credit in SciShield for you. It's that easy!

Abstract: The evolution of plasma environments is defined and governed by balances between ionizing processes, chemical rearrangements, and neutralisation reactions such as mutual neutralisation (MN). Measuring and explaining these processes in detail is fundamental to understanding and modelling non-local thermal equilibrium environments, such as atmospheric plasmas.

Until recently, experimental studies of MN involving molecular ions in flow tubes and merged-beams were limited to measurements of overall reactivities without information of the mechanism or the products. The cryogenic Double ElectroStatic Ion Ring ExpEriment facility makes such studies possible.

Here, it is possible to control and manipulate the internal energies of the ions, fine-tuned their collision energy, and identify the reaction products and the states they are in. This opens possibilities to reach new insights on balances between different MN reaction pathways and their dynamics, and here I focus on MN relevant to atmospheric phenomenon such as sprites: investigating reactions involving molecular oxygen and nitrogen ions, I probe competition between product channels and unravel effects of internal energy in the molecular ion on the reaction.

There is a long-standing history of instrument makers grilling bratwursts for the whole building every summer. We will be continuing the tradition outside by the tower Thursday July 31st at noon. Remember to pack your appetites and join us in the great American pastime of eating hot dogs until we all feel ill!

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Abstract: Galaxies are intimately connected to the environments they live in. The haloes around them contain the gas reservoir from which the galaxies grow, while galactic outflows heat and enrich this circumgalactic medium (CGM). The elemental abundances of present-day stars are, in part, set by these cosmic gas flows. Using zoom-in cosmological simulations of galaxies, I will discuss the physical and observable properties of gas and stars in and around galaxies. The multiphase nature of the CGM is affected by the resolution of our simulations, which enhances the amount of cool, neutral gas in the halo, bringing them more in line with observations. I will show how the properties of the CGM depend on the presence of magnetic fields and on feedback from relativistic cosmic rays. This affects the distribution of metals and observational properties of the halo gas. Our simulations also follow the distribution of rare elements beyond the iron peak, produced by rapid neutron capture and, time permitting, I will discuss whether or not neutron star mergers could be the main source of these heavy elements by comparing our results to observed stellar abundances.

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Abstract: In the last several years, the combination of resolved event horizon scale images and large-scale computational models has led to new insights into black hole accretion. The main implication is that magnetic fields near the event horizon can become dynamically important, and I'll show that such a scenario provides a natural explanation for the high energy flares from our Galactic center black hole. I’ll then discuss our efforts to extend beyond the two objects with resolved images and calculate theoretical predictions for more luminous systems, focusing on the maximum luminosity of a hot accretion flow and the physical origin of the X-ray corona.