High fidelity quantum memory via dynamical decoupling: theory and experiment

TL;DR

This paper demonstrates experimentally that concatenated dynamical decoupling significantly prolongs quantum state coherence, offering a promising method to combat decoherence in quantum information processing.

Contribution

First experimental validation of concatenated dynamical decoupling showing substantial coherence time improvement in nuclear magnetic resonance systems.

Findings

Near an order of magnitude increase in quantum state decay time.

Effective suppression of decoherence using recursive pulse sequences.

Potential for CDD to serve as a primary decoherence mitigation technique.

Abstract

Quantum information processing requires overcoming decoherence---the loss of "quantumness" due to the inevitable interaction between the quantum system and its environment. One approach towards a solution is quantum dynamical decoupling---a method employing strong and frequent pulses applied to the qubits. Here we report on the first experimental test of the concatenated dynamical decoupling (CDD) scheme, which invokes recursively constructed pulse sequences. Using nuclear magnetic resonance, we demonstrate a near order of magnitude improvement in the decay time of stored quantum states. In conjunction with recent results on high fidelity quantum gates using CDD, our results suggest that quantum dynamical decoupling should be used as a first layer of defense against decoherence in quantum information processing implementations, and can be a stand-alone solution in the right parameter regime.