The control of quantum systems on the basis of continuous weak measurement has been developed along two main lines: so-called Markovian feedback, where the measurement output is just amplified and sent back as a drive to the system; and state-based feedback, where a full density operator is estimated with a quantum filter and well-behaved or optimal corrections are computed accordingly. In terms of controller complexity, these are two extreme cases. Markovian feedback has limited performance, a full filter can be computationally heavy even for moderate systems at ultra-fast timescales. We will report on our recent efforts to design controllers of intermediate complexity. In a first development, we introduce a low-dimensional dynamics to improve the performance of Markovian feedback. In a second development, we discuss a novel nonlinear structure in the quantum stochastic differential equation, which can enable to significantly reduce the dimension of the quantum filter.
By Florian Marquardt
By Gary Steele
By Hendrik Bluhm
By Jean-Michel Raimond
By Alain Sarlette
By Sylvain Schwartz
By Sophia Economou
By Klaus Mølmer
By Howard M. Wiseman
By Michel Devoret
By Akira Furusawa
By Yanhong Xiao
By Alex Retzker
By Nicolas Didier
By Ivan Deutsch
By Mankei Tsang
By Aashish Clerk
By Valentina Parigi
By Rebing Wu
By Michael Biercuk
By Thomas Ayral
By Yassine Hamoudi
By Yassine Hamoudi
By Nana Liu
By Nana Liu
