April 30, 2003 , Miller Room, 12:30 PM
An Atomic Turing Machine: Quantum Computing with Trapped Ions at NIST
The basic features of quantum information processing using trapped ions will be briefly reviewed from Lecture 1. Our current work focuses on demonstrating the necessary ingredients to produce a scalable quantum computing scheme and on simplifying and improving quantum logic gates. Along these lines, I will speak about a new set of experiments that was made possible by recent improvements in trap technology. A novel trap with multiple trapping regions was used to demonstrate the first steps towards a fully scalable (multiplexed) quantum computing scheme. Single ions were "shuttled" between trapping regions without disturbing the ion's motional and internal state, and two ions were separated from a single to two different trapping zones.
Improvements in the trap manufacturing process has led to a reduction of nearly two orders of magnitude in the ion's motional heating rate, making possible two new improved logic gates. The first gate utilizes the wave-packet nature of the ions to tune the laser-atom interaction and achieve a controlled-NOT gate between a single ion's spin and motional states. The second, a two-ion phase gate, uses phase-space dynamics to produce a state-sensitive geometric phase. Both gates are simplified over a previous demonstration and achieve logic accuracies of 95% and 97%, respectively.
The lecture will end with two sneak previews: a quick look at ongoing work using a Mg ion to sympathetically cool a simultaneously trapped Be ion and a glimpse of the next generation of ions traps currently under construction.