[LA-SiGMA] TODAY: Dr. Kevin D. Osborn's Seminar, Wednesday February 13, 3:30 p.m.

[Bety Rodriguez-Milla]

Dear All,

This is a reminder about today's talk.

Regards,

-Bety

On Feb 8, 2013, at 11:30 AM, Bety Rodriguez-Milla wrote:

> Dear All,
> 
> Dr. Kevin D. Osborn of the Laboratory for Physical Sciences in College Park, MD, will be giving a seminar this Wednesday February 13, 2013 at 3:30 p.m. at Tilton Hall 305, Tulane University. The title of his talk is "Two-Level System Material Defects in Superconducting Qubit Dielectrics".
> 
> Abstract:
> Superconducting qubits have steadily improved their coherence time for over a decade such that quantum information algorithms are now implemented with an integrated circuit. However, material defects at the requisite millikelvin temperatures, often referred to as two-level systems (TLS), interact with the microwave photon fields and continue to limit the coherence of qubits.  These TLS also limit the performance of astronomy photon detectors, which are made with superconducting circuits. In this talk, I will focus on TLS which are electrically and resonantly coupled to the microwave fields, and are particularly troublesome for these devices. Unfortunately the microscopic model of these low temperature defects is often unknown, but I will argue that a particular Hydrogen-based defect recently identified by ab-initio calculations in alumina is the likely TLS defect. In addition, I will show how data from resonators allows one to quantify the influence of the TLS using the loss tangent.  Next I will show how non-equilibrium data on TLS can be taken with a new device called a microwave bridge resonator.  Coupled with new theoretical work, these measurements increase our understanding of TLS out of equilibrium, and allow the practical extraction of the TLS dipole moment.
> 
> About the speaker. 
> Dr. Kevin D. Osborn received his doctorate in physics from the University of Illinois at Urbana-Champaign in 2001, with a thesis on the critical fluctuations of the superfluid density in high-temperature superconducting films.  He then started postdoctoral research at the National Institute of Standards and Technology in Boulder, Colorado and measured individual InGaAs quantum dots using Al single-electron transistors.  In 2004 he received a National Research Council postdoctoral associate award which allowed him to perform studies at NIST on decoherence mechanisms in superconducting phase qubits.  In 2007 Dr. Osborn transitioned to the Laboratory for Physical Sciences in College Park, Maryland, to set up a new research group as a US government physicist.  His group currently studies decoherence mechanisms in superconducting qubits, with an emphasis on condensed matter phenomena related to two-level systems.
> 
> The seminar will be a live broadcast from Tulane University, and can be viewed live at the sites listed below:
> 
> LSU - Johnston Hall Room 338
> UNO - Liberal Arts Building 234
> Xavier - Qatar Pavilion Conference Room 226
> Southern University - JB Moore Hall, Room 211
> LATech -  PML 1015, Center for Instructional Technology, at the Wyly Tower.
> 
> The seminar will also be accessible via adobe connect by clicking on following link:  https://connect.lsu.edu/la-sigma/
> 
> Please let me know if you have any questions.
> 
> Regards,
> 
> -Bety
> 
> <KevinOsborn021313.pdf>
> 
> 
> _______________________________________________
> LaSiGMA mailing list
> LaSiGMA at loni.org
> https://mail.loni.org/mailman/listinfo/lasigma