Dipolar switching for robust quantum computation with polar molecules

University Of Connecticut, Storrs CT

Investigators

Abstract

Recent advances in our understanding of quantum information suggest that computational devices based on fundamental quantum principles, such as interference and entanglement, can perform certain tasks considerably more efficiently than any classical computer. The potential ramifications of computing devices based on these principles have inspired a great deal of effort aimed at determining the information processing power of such devices and possible methods for physically realizing them. In quantum processors, the information would exist in the form of superpositions of quantum bits, or qubits. To usefully manipulate qubits, they must interact in a controlled and coherent manner in order to preserve these superpositions. Of the many systems studied to manipulate quantum information, two platforms are especially attractive; trapped ions exhibit strong interactions and a high level of control, while neutral atoms have very long coherence times and well developed techniques to cool and trap them. Polar molecules represent a new platform that incorporates the best of both, atoms and ions, and may even bridge the gap with condensed matter physics approaches. Because they are neutral, they are easier to store in a dense fashion than ions, and because they have strong electric dipole moments, they interact with a much stronger and longer-range interaction than neutral atoms. In addition, the recent advances in cooling and storing of polar molecules are paving the way to the accurate manipulation of single molecules required for quantum computing. The research proposed involves the study of the implementation of universal two-qubit logic gates in ultracold polar molecules, focusing on switchable dipole-dipole interactions. With this new system, one may take advantage of the many internal molecular quantum states to encode and process information. The work will investigate schemes based on dipole interactions between polar molecules, taking advantage of their large range of dipole moments; by selectively exciting transitions from low- to high-dipole states in two molecules, using optical or microwave transitions, the interaction can effectively be controlled. The work will focus on two potential architectures, optical lattices and microtraps connected to superconducting wires. For these two approaches, we will be in close contact with our experimental collaborators at Harvard (Doyle/Lukin) and Yale (DeMille). In addition, we will explore the possibility of adapting the blockade mechanism for phase gate with polar molecules.