Robust and Efficient High-dimensional Quantum State Tomography

TL;DR

This paper introduces a practical and robust self-guided tomography method for high-dimensional quantum states, achieving record fidelities across various qudit systems and demonstrating broad applicability and noise resilience.

Contribution

The paper presents a novel self-guided tomography technique that efficiently characterizes high-dimensional quantum states with unprecedented fidelities and robustness against noise.

Findings

Fidelities over 99.9% for qutrits and ququints

Fidelity of 99.1% for quvigints (d=20)

Robustness against statistical and environmental noise

Abstract

The exponential growth in Hilbert space with increasing size of a quantum system means that accurately characterising the system becomes significantly harder with system dimension d. We show that self-guided tomography is a practical, efficient, and robust technique of measuring higher-dimensional quantum states. The achieved fidelities are over 99.9% for qutrits (d=3) and ququints (d=5), and 99.1% for quvigints (d=20), the highest values ever realised for qudits. We demonstrate robustness against experimental sources of noise, both statistical and environmental. The technique is applicable to any higher-dimensional system, from a collection of qubits through to individual qudits, and any physical realisation, be it photonic, superconducting, ionic, or spin.