Special 290S/290K Quantum Materials Seminar speaker Matthew Powell (UC Irvine) Tuesday, December 6 at 3:30 pm in 402 Physics South

Time/Venue Tuesday, December 6 at 3:30 pm in Pacific time in 402 Physics South and via Zoom:
https://berkeley.zoom.us/j/99523499113pwd=REovb3pyam03WXQwbEhrU3dqNHZvdz09
Meeting ID: 995 2349 9113 Passcode: 600704
Host Joel Moore
Title Continuity of the Lyapunov exponent for analytic multi-frequency quasi-periodic cocycles
Abstract The purpose of this talk is to discuss our recent work on multi-frequency quasi-periodic cocycles, establishing continuity (both in cocycle and jointly in cocycle and frequency) of the Lyapunov exponent for non-identically singular cocycles. Analogous results for one-frequency cocycles have been known for over a decade, but the multi-frequency results have been limited to either Diophantine frequencies (continuity in cocycle) or $SL(2,\C)$ cocycles (joint continuity). We will discuss the history of this problem and the main points of our argument, which extends earlier work of Bourgain.