Events at Physics
Events on Thursday, March 22nd, 2012
- R. G. Herb Condensed Matter Seminar
- Quantum and classical fluctuation phenomena in low-dimensional superconductors
- Time: 12:00 am
- Place: CANCELLED
- Speaker: Victor Galitski, University of Maryland -- CANCELLED
- Abstract: Low-dimensional superconductivity provides a unique area in which a fascinating variety of novel and fundamental phenomena occur. In this talk, I will review recent theoretical and experimental work on superconducting fluctuation phenomena in low-dimensional superconductors. First, I will discuss unusual phases and fluctuation effects evident in the experimental studies of the field-tuned transition in two-dimensional disordered superconducting films and describe our theory of quantum superconducting fluctuations, which explains anomalous transport and thermal transport observed in the vicinity of the transition in these films. Next, I will focus on the recent experiment by the Penn State group [Wang et al., Nature Physics 6, 389 (2010)] on the long-range proximity effect in ferromagnetic nanowires proximity-coupled to superconducting electrodes. I will propose an explanation for both the anomalously-strong proximity effect and the mysterious resistance peak that preempts the superconducting transition in this experiment. In conclusion, I will discuss this and related setups involving ferromagnetic nanowires in the context of one-dimensional topological superconductors.
- Host: Vavilov
- Astronomy Colloquium
- TIdes and magnetic fields in Hot Jupiter Systems
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Evgenya Shkolnik, Lowell Observatory
- Abstract: Hot Jupiters, located only a few stellar radii from their parent stars, provide a laboratory in which we can study fundamental system parameters including planetary magnetic fields, a key component to understanding the planet's internal structure and atmospheric conditions. Over a dozen studies of hot Jupiter systems have independently converged on the same scenario: a short-period planet can induce activity on the photosphere and upper atmosphere of its host star, making the star itself a probe of its planet. This makes star-planet interactions (SPI) currently the most promising way to study exoplanetary magnetic fields. In addition, strong tidal interactions between the hot Jupiter and its star will increase the stellar rotation rate as well as the global stellar activity level, provided that the planet migrated early on in the system's history. Studying the tidal and magnetic interactions in such planetary systems builds our understanding of the formation, migration and evolution of close-in planets.
- Host: Ben Brown