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Week of September 15, 2019

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Ania Bleszynski Jayich - UC Santa Barbara

Ania Bleszynski Jayich - UC Santa Barbara

Mon, 09/16/2019 - 12:30pm
Pupin Hall Theory Center, 8th Floor


"Quantum sensing and imaging with diamond spins"

The nitrogen vacancy (NV) center in diamond is an atomic-scale defect in diamond that is highly sensitive to a wide variety of fields: magnetic, electric, thermal, and strain. A versatile quantum sensor, the NV center holds particular promise for nanometer-scale imaging. Here I discuss an NV-based imaging platform where we have incorporated an NV center into a scanning probe microscope and used it to image a variety of condensed matter systems, including skyrmions, nanoscale topological spin textures, as well as current flow patterns in graphene. I also discuss recent experiments that utilize the NV center’s sensitivity to fluctuating magnetic fields to image conductivity with nanoscale spatial resolution. A grand challenge to improving the spatial resolution and magnetic sensitivity of the NV is mitigating surface-induced quantum decoherence, which I will discuss in the second part of this talk. Decoherence at interfaces is a universal problem that affects many quantum technologies, but the microscopic origins are as yet unclear. Our studies guide the ongoing development of quantum control and materials control, pushing towards the ultimate goal of NV-based single nuclear spin imaging.

About the speaker

Ania Bleszynski Jayich received her Ph.D. in Physics from Harvard in 2006 and her B.S. in Physics and Mathematical and Computational Science from Stanford in 2000. Under the supervision of Prof. Bob Westervelt, her thesis focused on scanned probe imaging of electron flow in semiconductor nanostructures. As a postdoc in Prof. Jack Harris's group at Yale, she worked on magnetization measurements of condensed matter systems using ultrasensitive micromechanical detectors. Before joining UCSB as an assistant professor in 2010, she worked on coupling nitrogen-vacancy centers in diamond to nanomechanical resonators, in a project co-supervised by Profs. Misha Lukin at Harvard and Jack Harris.

The Jayich Lab at UCSB studies quantum effects on the nanoscale. They focus on nanoscale imaging of spin and charge in condensed matter systems, with an eye on applications in quantum and classical computing and biology. The lab is also interested in hybrid quantum systems consisting of spin, phonons and photons.

More details on Ania's research can be found here.

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09/16/2019 - 12:30pm
Soubhik Kumar - University of Maryland

Soubhik Kumar - University of Maryland

Mon, 09/16/2019 - 2:10pm
Pupin Hall Theory Center, 8th Floor


"Primordial Non-Gaussianity as a probe of (ultra high-energy) gauge theories"

Future measurements of primordial non-Gaussianity (NG) can reveal the mass and the spin information of cosmologically produced particles with masses of order the inflationary Hubble scale, H_inf, which can be as high as 10^13 GeV. In this talk, I will describe how such NG measurements can be used as an on-shell probe of, a) Grand Unified Theories and, b) low scale gauge theories that get “heavy-lifted” to ~ H_inf scales. I will also discuss a simple alternative to the standard inflationary paradigm, involving a curvaton field, that can allow NG signals orders of magnitude larger compared to standard inflation. This brings various motivated particle physics signatures, such as loops of heavy gauge-charged scalars and fermions, within future observational reach.

About the speaker

Soubhik Kumar is currently a graduate student at the University of Maryland working on theoretical particle physics. He completed his undergraduate degree in Physics from Kolkata, India.

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09/16/2019 - 2:10pm
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