Hope College Physics Department
Research Experiences for Undergraduates
Summer 2009
Project Summary


Project Title: Time-Reversal Symmetry Breaking in the Non-Linear Distortion from Superconducting Circuits
Student Name: Evan Pease
Student's Home Institution: Kenyon College
Research Advisor: Dr. Stephen Remillard
Source of Support: This material is based upon work supported by the National Science Foundation under NSF-REU Grant No. PHY-0452206, the Research Corp. for Science Advancement, and an R&D contract from Mesaplexx, pty ltd.

High-temperature superconductors (HTS) make compact and low-loss filters for microwave circuits. HTS filters are known to produce harmonic and intermodulation distortion (IMD). Distortion created by the filters will set the limits for use in microwave technologies, and its observation provides a better physical understanding of the electrodynamics of the HTS materials. Multi-tone measurements can be performed to detect the distortion, and the three-tone technique developed at Hope College allows simultaneous measurement of even and odd order distortion currents. Despite earlier predictions of only odd order non-linearity arising from HTS materials, both even and odd order distortion was observed. This is experimental evidence of time-reversal symmetry breaking in superconducting current. The observed catastrophic increase in only the odd order IMD levels near the transition temperature, Tc, is consistent with the expectations of the non-linear Meissner effect in HTS. The absence of such a catastrophe in the even order distortion indicates a higher order of time-reversal symmetry in conduction near Tc. _________________________________________________________________________________________________________________________________________________________
Publications and Presentations:
"Time-Reversal Symmetry Breaking in the Non-Linear Distortion from Superconducting Circuits", Evan K. Pease and S.K. Remillard, American Physical Society, March Meeting, March, 2010.
"Synchronous measurement of even and odd order intermodulation distortion at the resonant frequency of a superconducting resonator", Evan K. Pease, Bradley J. Dober, and S.K. Remillard, Review of Scientific Instruments,
vol. 81, 024701 (2010).
"Even and Odd Order Nonlinearity from Superconductive Microstrip Lines,"Annelle M. Eben, V. Andrew Bunnell, Candace J. Goodson, Evan K. Pease, Sheng-Chiang Lee, and S.K. Remillard, IEEE Trans. on Applied Superconductivity, Vol. 21, no. 3, pp. 595-598, (2011). .