Using the Quantum Zeno Effect for Suppression of Decoherence

TL;DR

This paper demonstrates how the quantum Zeno effect can be used to protect a nuclear spin qubit's superposition state from decoherence, offering a method to stabilize quantum states without ensemble averaging.

Contribution

The study shows experimental implementation of the quantum Zeno effect for state preservation in a nuclear spin qubit using an ancilla for measurement, and proposes a scheme for general state protection.

Findings

Quantum Zeno effect can suppress decoherence in nuclear spin qubits.

Protection of superposition states achieved without ensemble averaging.

Proposed scheme enables arbitrary state protection using QZE.

Abstract

Projective measurements are an essential element of quantum mechanics. In most cases, they cause an irreversible change of the quantum system on which they act. However, measurements can also be used to stabilize quantum states from decay processes, which is known as the quantum Zeno effect (QZE). Here, we demonstrate this effect for the case of a superposition state of a nuclear spin qubit, using an ancilla to perform the measurement. As a result, the quantum state of the qubit is protected against dephasing without relying on an ensemble nature of NMR experiments. We also propose a scheme to protect an arbitrary state by using QZE.