When: Tuesday 15th March 2016, starting at 6.00 pm.

Where: Renaissance Baltimore Harborplace Hotel, 202 E. Pratt Street, Baltimore, MD 21202, USA.

Guest speaker: Dr Mohammad Hamidian, Harvard University, MA, USA - winner of the 2016 Lee Osheroff Richardson Science Prize.

Talk Title: Directly Imaging the Super States of Nature.

Dr Hamidian’s research focuses on exotic phases of quantum electronic matter and the development of computational and experimental tools to directly visualize them at the atomic scale.

Talk abstract:

A superconductor is formed when electrons in a material bind into Cooper-pairs and condense into a quantum mechanical fluid permeating the solid and flowing with zero resistance. Conventional understanding of superconductivity tells us that this charged superfluid must be spatially uniform. But alternative electron pairing schemes, which have long been proposed, could generate a new phase of superconductor, the FFLO state [1,2], in which the pairs force the superconducting fluid to spatially oscillate.  Despite decades of focused research, however, this new class of superconductor has evaded direct observation.  The hunt has recently intensified in the field high temperature superconductivity where the presence of a modulated superfluid in the cuprates, referred to as a Pair Density Wave, could provide a missing link to unify our understanding of the complex phase diagram and ultimately the mechanism for high temperature superconductivity.   To address this pressing issue we developed a milli-Kelvin nanometer resolution Scanned Josephson Tunneling Microscope (SJTM) to search for the pair density wave in the cuprates [3].  Capable of directly visualizing the quantum fluid of Cooper pairs at every spatial location in the material, the images, the first to be made in any condensed matter system, revealed the long sought modulated superfluid.

[1] Fulde, P. & Ferrell, R. A.   Phys. Rev. 135, A550 (1964).

[2] Larkin, A. I. & Ovchinnikov, Yu. N.  Zh. Eksp. Teor. Fiz. 37, 1146 (1964).

[3] M. H. Hamidian et al. (To Appear in Nature 2016)  arXiv:1511.08124

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