Demonstration of universal control between non-interacting qubits using the Quantum Zeno effect

TL;DR

This paper demonstrates how the Quantum Zeno effect can be used to create entangling gates between non-interacting qubits, enabling universal quantum control through measurement-induced dynamics rather than direct interactions.

Contribution

It introduces a method to generate entangling gates via the Quantum Zeno effect in non-interacting qubits, expanding quantum control techniques beyond coherent interactions.

Findings

Successfully implemented a Zeno-based entangling gate between non-interacting transmon qubits

The gate imparts a geometric phase conditioned on a non-local subspace

Demonstrates universality in quantum control through measurement rather than interaction

Abstract

The Zeno effect occurs in quantum systems when a very strong measurement is applied, which can alter the dynamics in non-trivial ways. Despite being dissipative, the dynamics stay coherent within any degenerate subspaces of the measurement. Here we show that such a measurement can turn a single-qubit operation into a two- or multi-qubit entangling gate, even in a non-interacting system. We demonstrate this gate between two effectively non-interacting transmon qubits. Our Zeno gate works by imparting a geometric phase on the system, conditioned on it lying within a particular non-local subspace. These results show how universality can be generated not only by coherent interactions as is typically employed in quantum information platforms, but also by Zeno measurements.