Eliminating qubit type cross-talk in the $\text{omg}$ protocol

Abstract

The $\text{omg}$ protocol is a promising paradigm that uses multiple, application-specific qubit subspaces within the Hilbert space of each single atom during quantum information processing. A key assumption for $\text{omg}$ operation is that a subspace can be accessed independently without deleterious effects on information stored in other subspaces. We find that intensity noise during laser-based quantum gates in one subspace can cause decoherence in other subspaces, potentially complicating $\text{omg}$ operation. We show, however, that a magnetic-field-induced vector light shift can be used to eliminate this source of decoherence. As this technique requires simply choosing a certain, magnetic field dependent, polarization for the gate lasers it is straightforward to implement and potentially helpful for $\text{omg}$ based quantum technology.

5 + 3 pages, 3 + 2 figures