Joint Quantum Information Seminar
Professor Daniel A. Lidar
University of Southern California
Friday, 12 August at 2:00pm
Pfizer Lecture Hall
Mallinckrodt Building, Ground Floor
12 Oxford Street, Harvard Campus
Hosted by the Department of Chemistry & Chemical Biology (CCB) and Institute
for Theoretical Atomic, Molecular & Optical Physics (ITAMP) at Harvard
Coffee and cookies will be provided.
Title and Abstract:
Encoded weak quantum Zeno effect for quantum computation and control
The Zeno effect is one of the oldest, if not the oldest, quantum error
prevention protocols. It is well known since Misra & Sudarshan's work in the late seventies that it can be used to protect specific quantum states from decoherence by using strong, projective measurements. In this talk I will explain how to both generalize the scope of this result and relax its underlying assumptions. In particular, I will show how to combine the theory of weak, non-selective measurements with stabilizer quantum error correction and detection codes, in order to implement an "encoded weak quantum Zeno effect" (EWQZE, pronounced "youkzee"). We have derived rigorous performance bounds which demonstrate that the EWQZE can be used to protect arbitrary, but appropriately encoded states to any accuracy, while at the same time allowing for universal quantum computation or quantum control. While higher accuracy requires an increased measurement repetition rate, surprisingly, any non-vanishing measurement strength will suffice.
Joint work with Jason Dominy, Gerardo Paz, and Ali Rezakhani. Preliminary results reported in arXiv:1104.5507.