Qudit

2025-11-03T11:31:24Z

2605:A601:AA77:3100:44F6:C283:B0EA:FBE4: minor grammer correction (captalizing a word at the start of a sentence, adding commas)

{{Short description|Unit of information in a quantum computer}}

In [[quantum computing]], a qudit (/ˈkjuː/dɪt/) or quantum dit is the generalized unit of quantum information described by a superposition of ''d'' states, where the number of states is an integer equal to or greater than two.

== Qudit versus qubit ==
A qudit, characterized by d=2 states is a [[qubit]] .<ref>{{Cite web |title=What is a Qudit? Advantages & Use Cases |url=https://www.quera.com/glossary/qudit |access-date=2025-09-21 |website=www.quera.com}}</ref>

Qudits with d states greater than 2 can provide a larger Hilbert space, providing more ways to store and process quantum information.<ref>{{Cite journal |last1=Meth |first1=Michael |last2=Zhang |first2=Jinglei |last3=Haase |first3=Jan F. |last4=Edmunds |first4=Claire |last5=Postler |first5=Lukas |last6=Jena |first6=Andrew J. |last7=Steiner |first7=Alex |last8=Dellantonio |first8=Luca |last9=Blatt |first9=Rainer |last10=Zoller |first10=Peter |last11=Monz |first11=Thomas |last12=Schindler |first12=Philipp |last13=Muschik |first13=Christine |last14=Ringbauer |first14=Martin |date=2025-03-25 |title=Simulating two-dimensional lattice gauge theories on a qudit quantum computer |journal=Nature Physics |language=en |volume=21 |issue=4 |pages=570–576 |doi=10.1038/s41567-025-02797-w |issn=1745-2473 |pmc=11999872 |pmid=40248572 |arxiv=2310.12110 |bibcode=2025NatPh..21..570M }}</ref><ref>{{Cite journal |last1=Meng |first1=Zhe |last2=Liu |first2=Wen-Qiang |last3=Song |first3=Bo-Wen |last4=Wang |first4=Xiao-Yun |last5=Zhang |first5=An-Ning |last6=Yin |first6=Zhang-Qi |date=2024-02-20 |title=Experimental realization of high-dimensional quantum gates with ultrahigh fidelity and efficiency |url=https://link.aps.org/doi/10.1103/PhysRevA.109.022612 |journal=Physical Review A |volume=109 |issue=2 |article-number=022612 |doi=10.1103/PhysRevA.109.022612 |arxiv=2311.18179 |bibcode=2024PhRvA.109b2612M }}</ref>

== Qudit States ==

* [[Qubit]] - Qudit with d=2 states

* [[Qutrit]] - Qudit with d=3 states

* Ququart - Qudit with d=4 states

== Error Correction ==
[[Quantum decoherence]] is the natural process where quantum information is lost due to environmental interaction and [[quantum error correction]] is a technique that actively combats decoherence.

In a paper published September 2025, researchers demonstrate a new hybrid method that encodes information in both light and matter using a [[cat state]] qudit with d>2 which allows for the detection of photon loss through the parity syndrome by entangling a light pulse with ancillary qubits. This method achieves parallel Bell-pair generation by leveraging the multi-level nature of the qudit.<ref>{{Citation |last1=McIntyre |first1=Z. M. |title=Loss-tolerant parallelized Bell-state generation with a hybrid cat qudit |date=2025-09-10 |arxiv=2509.08577 |last2=Coish |first2=W. A.}}</ref>

== Qudit Logic Gates ==
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.

== 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.<ref>{{Citation |last1=Ilikj |first1=Branislav |title=Ramsey Interferometry with Qudits |date=2025-09-08 |arxiv=2509.06290 |last2=Vitanov |first2=Nikolay V.}}</ref>

== References ==
<references />{{Compu-stub}}
[[Category:Quantum computing]]
[[Category:Units of information]]
[[Category:Quantum states]]

Vero - Wikipedia - User contributions [en]

Qudit