| Monday September 14, 2009 3:00 PM | Robert Throckmorton | Theory of site-selective NMR in d-wave superconductor A new mechanism for relaxing the nuclear magnetic moments, which dominates at low temperature, is identified in type-II d-wave superconductors in an external magnetic field above Hc1. The results of this theory are compared with the NMR experiments on YBCO in high magnetic fields and found to agree without invoking antiferromagnetic order in the vortex core. http://arxiv.org/abs/0908.4268 | CMS Library |
| Monday September 21, 2009 3:00 PM | Seiji Yamamoto | On the Importance of Being First By taking advantage of arXiv submission policies, it is relatively easy for authors to arrange for an article to appear first, or at least very early, in the public listings of daily submissions to the arXiv. Indeed, submission rates between 4:00pm-4:10pm EST are five times higher than any other time of day. But is there compelling evidence that this sort of behavior has any effect on a paper's future impact? Dietrich (2007, 2008) and Haque and Ginsparg (2009) have found a statistically significant positive correlation between early placement in the list on any single day, and an increase in long-term citation count. So, empirically, early listing seems to make a difference, but how much? Articles listed in position 1 garnered 83 percent more citations than average for astro-ph, whereas position 1 articles in hep-th and hep-ph received 50 and 100 percent boosts in citations. So the effect is statistically significant and large, but why? Kurtz suggested the Open Access, Early Access, and Self-selection Bias postulates. Dietrich put forth the Visibility Bias, Self-Promotion Bias, and Geography Bias effects. Haque and Ginsparg used some fancy statistics to refine the Dietrich results. The central debate is whether authors tend to heavily promote papers that they know are intrinsically better, or if the citation boost is purely due to the added visibility of being listed first. I'll discuss one way they have found to statistically uncover and quantify the answer to this question. http://arxiv.org/abs/0907.4740 http://arxiv.org/abs/0805.0307 http://arxiv.org/abs/0712.1037 | CMS Library |
| Monday September 28, 2009 3:00 PM | Rob Smith | NMR experiments in cuprates | |
| Monday October 5, 2009 3:00 PM | Jose Abel Hoyos Neto | From Bouncing to Floating: Noncoalescence of Drops on a Fluid Bath Phys. Rev. Lett. 94, 177801 (2005) Y. Couder, E. Fort, C.-H. Gautier, and A. Boudaoud Dynamical phenomena: Walking and orbiting droplets Nature 437, 208 (2005) Y. Couder, S. Protière, E. Fort, and A. Boudaoud Single-Particle Diffraction and Interference at a Macroscopic Scale Phys. Rev. Lett. 97, 154101 (2006) Yves Couder and Emmanuel Fort | CMS Library |
| Monday October 19, 2009 3:00 PM | Yafis Barlas | Experimental Observation of the Fractional Quantum Hall Effect in Graphene http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08522.html http://arxiv.org/abs/0910.2763 | CMS Library |
| Monday November 9, 2009 3:00 PM | Arkady Shekhter | Recent mu-+ experiments to search for magnetc order in underdoped cuprates PRL 101, 227004 (2008) Recent mu+SR experiments present an opportunity to consider the charge screening in cuprates. The planar nature of the structure and the strong correlation physics that sustain metallic behavior in cuprates play important role in our interpretation of the results of the experiments. We also briefly mention implications for NMR. | CMS Library |
| Tuesday November 10, 2009 3:30 PM | Takemichi Okui | Tutorial: AdS/CFT Correspondence I | CMS Library |
| Monday November 16, 2009 3:00 PM | Scott Riggs | Quantum Oscillations in the Specific Heat of YBCO We measure the specific heat of underdoped YBCO in magnetic fields up to 45T in order to provide a first study of the thermodynamics of the normal state in the high temperature superconducting cuprates. Our experiments are motivated by quantum oscillation measurements of resistivity and magnetization over the past several years that have been interpreted in the context of the standard Lifshitz-Kosevich (LK) formalism for conventional metals. We find quantum oscillations in the specific heat of the cuprates for the first time ever and reveal that the normal state exhibits a seemingly-contradictory mixture of conventional and unconventional behavior. We find that LK theory can quantitatively describe the temperature-dependence of the specific heat as well as the temperature- and field-dependence of the quantum oscillations in specific heat. However, the magnetic field dependence of the specific heat follows the behavior of the superconducting state over our entire magnetic field range. As the superconducting state is suppressed (Tc --> 0) at ~30T in this sample, why does specific heat at 45T give evidence for a superconducting gap? And why does metallic LK behavior persist below 30T, in fact throughout the superconducting regime? Some ideas will be presented. | CMS Library |
| Wednesday November 18, 2009 3:30 PM | Takemichi Okui | Tutorial: AdS/CFT Correspondence II | CMS Library |
| Wednesday December 2, 2009 3:30 PM | Takemichi Okui | Tutorial: AdS/CFT Correspondence III | CMS Library |
| Monday December 7, 2009 3:00 PM | Wenxin Ding | Graduate level introduction to entanglement entropy (EE) A 15min introduction to basics of entanglement entropy in the context of condensed matter theory. Just graduate-level, starting from reduced density matrix, a Schmidt decomposition, followed by an example of coupled harmonic oscillators. Then I list some important results or applications, including EE in one dimensional systems, area law, EE of free fermions in arbitrary dimensions, topological entanglement entropy, EE and DMRG, matrix product states, etc. Entanglement in Many-Body Systems Rev. Mod. Phys. 80, 517 (2008) Area laws for the entanglement entropy - a review http://arxiv.org/abs/0808.3773 | CMS Library |