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A Single-Ion Perspective on the Environment

Event Details

Event Dates: 

Monday, October 15, 2012 - 5:00am

Speaker Name(s): 

Shlomi Kotler

Speaker Affiliation(s): 

Weizmann Institute of Science, Israel
Seminar Type/Subject

Event Details & Abstract: 

Cold trapped ions are well isolated and controlled platforms for quantum information and metrology. Captured in vacuum, far from any solid state environment and cooled to their mechanical ground state, ions exhibit fantastic coherence times.We study the remaining inevitable influence of the environment in twodirections: 1.Quantum Environment -the electric vacuum. Can one reverse the process of spontaneous photon scattering and retain coherence? Using the information stored in the escaping photon we were able to coherently reverse the process in real time obtaining > 85 % correction fidelity whenever the photon was detected. We discuss the mechanism behind this and show that the ion-photon interaction chooses a measurement basis for the ion, breaking the symmetry of the ion wave-function collapse. 2.Classical Environment -the magnetic field. We developed a set of tools which enabled us to turn the coherence time of a Zeeman sensitive qubit from the typical 1 ms to 1.4 s. With these techniques, most notably the quantum lock-in method, the magnetic field sensitivity reached $15 pT/sqrt{Hz}$, currently a record for single spins. We discuss the implications of this result on our current effort to directly observe electron spin-spin interaction at a distance of 2 microns.