Qudit

A qudit logic gate (or simply qudit gate) is a basic quantum circuit that acts on a qudit.

To achieve a universal qudit gate, (a gate that can be used to approximate any unitary transformation on a quantum computer to an arbitrary degree of accuracy) a set of gates must include a finite set of single qudit gates and at least one two qudit entangling gate that can create entanglement between qudits.

Qudit Control

Qudit control is the precise navigation of a qudit’s quantum state through engineered signals to perform quantum computations.

In a paper published December 16, 2025 a team of researchers achieved a breakthrough in qudit control by engineering five level qudits through individually addressable transitions between Zeeman sublevels (see also Zeeman Effect), achieved by combining a large linear Zeeman shift with a state-dependent light shift. Simulations predict state-preparation fidelities of F ≃ 0.99 within ∽1 μs , single-qudit gate fidelities of F ≃ 0.99 with π pulse durations of ∽ 2.5 μs, and fast destructive imaging with durations below 10 μs . These results establish a broadly applicable framework for high-fidelity control of Zeeman sublevel-encoded qudits and a promising platform for scalable qudit-based quantum technologies.

Use In Measurement

Quantum information is traditionally used in Ramsey interferometry, a technique used for precise measurement across various areas of science and technology.

Qudits with d>2 have shown to increase precision and resolution of quantum measurements. Qutrits, for example, have shown to achieve a twofold increase in resolution compared to qubits without any reduction in measurement contrast.