Events on Thursday, February 14th, 2019
- R. G. Herb Condensed Matter Seminar
- Quantum realizations of non-Hermitian (PT-symmetric) systems
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Prof. Yogesh Joglekar, Indianapolis
- Abstract: Open systems with gain or losses, or both, described by non-Hermitian Hamiltonians, have been a subject of intense research recently. In classical optical systems, the effect of exceptional-point degeneracies on their dynamics has been observed through remarkable phenomena such as the parity-time (PT) symmetry breaking transition, asymmetric mode switching, and optimal energy transfer. After a brief history of the field of PT-symmetry, started by Carl Bender and co-workers, I will discuss quantum realizations of such systems with single photons, ultracold atoms, and superconducting transmon circuits. Results include observation of PT transitions at vanishingly small non-Hermiticity in the Floquet domain, information flow in a PT-symmetric system, and a quantum signature of the exceptional point in the qubit relaxation state. I will argue that non-Hermiticity provides a new dimension for exploring quantum systems. * Work in collaboration with Dr. Anthony Laing (University of Bristol), Prof. Le Luo (Sun Yat-Sen University), and Prof. Kater Murch (Washington U.).
- Host: Saffman
- Cosmology Journal Club
- Time: 12:00 pm - 1:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
http://cmb.physics.wisc.edu/journal/index.html
Feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Ross Cawthon (cawthon@wisc.edu) and Santanu Das (sdas33@wisc.edu). - Astronomy Colloquium
- Tracing the chemical origins of exoplanetary worlds
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins 3:45 PM
- Speaker: Ke (Coco) Zhang, University of Michigan
- Abstract: We have learned that exoplanets are not only common in the Galaxy but also incredibly diverse, ranging from large to small, from rocky to hydrogen gas-rich. These discoveries raise many questions about planet formation, evolution, and habitability. To address these questions, a wealth of information can be learned from making connections between the chemical compositions of raw materials in natal planet-forming disks to compositions of exoplanet atmospheres. For this talk, I will focus on making connections through two abundant elements -- carbon and oxygen-- from young disks to exoplanets. I will discuss current observations and theoretical studies on how these elemental abundances vary with location and time at planet-forming scales. I will also discuss recent discoveries of AU-scale substructures in ALMA observations of disks and place these results in the context of our growing understanding of the chemistry and physics associated with planet formation. I will conclude with a discussion of the fantastic future using ALMA and, eventually JWST, that will zoom in to characterize the chemical/physical properties of the planet-forming zone and characterize the habitable zone in disks surround M dwarfs.
- Host: Professor Snezana Stanimirovic