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Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor

May 15, 2014
Schematic of the high-DOS regions which contribute to QPI

Superconductivity arises from pairing of electrons on the Fermi surface. Professors Jenny Hoffman and Subir Sachdev, with colleagues from Harvard, MIT, Nagoya University, and Northeastern University report in Science that they used Fourier transform STM to map a small-to-large Fermi surface transition in the cuprate superconductor Bi2-yPbySr2-xLaxCuO6+d, demonstrating a quantum critical point near optimal doping at zero field. The researchers showed that superconductivity coexists with the pseudogap on the recovered antinodal Fermi surface above optimal doping.

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Emanuele Dalla Torre Awarded the Alon Fellowship

May 13, 2014
Dr. Dalla Torre

Dr. Dalla Torre was awarded the Alon Fellowship for young faculty members by the Israeli Council for Higher Education. He is currently a post-doctorate fellow at the Department of Physics, in the group of Prof. Eugene Demler, and an ITAMP fellow. Next year Dr. Dalla Torre is heading to Bar Ilan University. His research focuses on the non-equilibrium dynamics of many-body systems; more details can be obtained from his (future) group's website at http://www.nonequilibrium.org

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Gamma-Ray Emissions from Dark Matter?

April 10, 2014

Past studies have identifed a spatially extended excess of 1-3 GeV gamma rays from the region surrounding the Galactic Center, consistent with the emission expected from annihilating dark matter.  Harvard Physics grad student Tansu Daylan, Prof. Douglas Finkbeiner, and researchers from Fermilab, University of Chicago,  MIT, and Princeton revisited and scrutinized this signal with the intention of further constraining its characteristics and origin.

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Topological Excitations and the Dynamic Structure Factor of Spin Liquids on the Kagome Lattice

April 1, 2014
ac, Plots of S(k,ω) at zero temperature for different spinon–vison interaction strengths as a function of frequency and momentum along the high-symmetry directions between the Γ, M and K points of the extended Brillouin zone, indicated by the blue arrows in e. a, Non-interacting spinons. Note that in the Q1=Q2 state two of the three spinon bands are degenerate, whereas the third, highest energy spinon band is flat.

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