Upcoming Seminars:
Dept of Physics & Astronomy
University of British Columbia
A central debate in the field of high-temperature superconductivity (“the ability to conduct electricity without resistance at record high temperatures”) is the nature of the underlying normal state. Is this a fluid of independent electrons with renormalized mass and velocity, as the 'Fermi liquid quasiparticles' that give rise to conventional low-temperature superconductivity? Or is instead a property emerging from the unconventional many-body physics of strongly correlated electrons? I will discuss this question, in the context of the copper oxides high-temperature superconductors, showing how we can use modern angle-resolved photoemission spectroscopy and a novel approach to control the number of electrons at the surface of these materials to probe electronic correlations [1], and whether these can wipe quasiparticles completely out of existence [2].[1] M.A. Hossain et al., Nature Physics 4, 527 (2008).
[2] D. Fournier et al., Nature Physics 6, 905 (2010).
Thursday, February 2, 2012 Room 101 Sir James Dunn Building 11:30 am*** Light lunch will be provided ***
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Assistant Professor of Physics & Ingenuity New Faculty
Complexity Science Group
Department of Physics and Astronomy
University of Calgary
One of the main features of seismicity is its energy-scale invariance as documented by the empirical Gutenberg-Richter law. It states that the frequency energy distribution of earthquakes decays as a power law indicating the absence of any characteristic scale. This law is observed to hold from the largest earthquakes down to atomic scales. I will discuss these and other empirical features of tectonic seismicity, induced seismicity and rock fracture from the perspective of statistical seismology and hazard assessment. In particular, I will focus on the spatio-temporal clustering of seismicity. From a physical perspective, the clustering of earthquakes indicates that the vast majority of them are triggered by the preceding ones due to static or dynamic stress changes, fluid flow, afterslip and/or other mechanisms. Establishing causal connections in a systematic way remains one of the main challenges in the field. I will present a recently introduced statistical procedure to identify such connections and show that dynamic stress changes play a significant role for the triggering of earthquakes.Thursday, January 26, 2012
Room 101
Sir James Dunn Building
11:30 am
*** Light lunch will be provided ***