The 6 different types of quantum computing technology

Types of quantum computing

Some types of quantum computing are more mature than others, but industry executives note that no single mode stands out as the clear champion at this point. Here's a rundown of the six main types of quantum computing in use today.

1. Annealing

Quantum annealing uses superconducting qubits, as does the superconducting modality explained below, but it employs different techniques and an analog computing model. Annealers are geared to optimization problems, such as determining the most efficient delivery route or balancing an investment portfolio. To solve such issues, quantum annealing uses superposition to evaluate possible solutions simultaneously based on their respective energy states. Another mechanism, quantum tunneling, helps identify the optimal way to solve the given problem, known as the minimum-energy solution.

The key benefit of quantum annealing machines is their focus on solving complicated optimization problems. Their inherent parallelism and use of tunneling can speed up those computational tasks. The vast majority of quantum annealing adopters use them for optimization use cases, said Sam Lucero, formerly chief analyst for quantum computing at Informa TechTarget's Omdia market research group.

Annealing, however, is considered less versatile than other forms of quantum computing. Another challenge: Analog computers can't use quantum error correction (QEC) techniques other quantum machines use to improve reliability, Lucero noted.

Quantum annealing vendors include D-Wave Systems, which was first to market in 2011, and Qilimanjaro Quantum Tech.

2. Superconducting

Superconducting quantum computers rely on electronic circuits to create qubits. This approach uses microwave pulses to implement quantum gates, which create superposition in the qubits or entangle them. The pulses manipulate the qubits' quantum states to run computations.

Computational speed is a plus for superconducting qubits, which use zero electrical resistance and the fine-tuned microwave control mechanism. This model also benefits from being able to use established semiconductor manufacturing techniques.

However, superconducting qubits are highly sensitive to environmental noise and have shorter lifespans than other modalities. In addition, superconducting quantum computers rely on cryogenic cooling systems, such as dilution refrigerators, which add to the cost. Such refrigeration, required for superconductivity, lets qubits operate at near absolute zero to minimize interference from thermal energy.

Google, IBM, IQM, Oxford Quantum Circuits and Rigetti Computing are among the providers of superconducting quantum technology. AWS, meanwhile, uses superconducting cat qubits in its prototype quantum chip, which the company unveiled in February. According to AWS, cat qubit technology reduces the resources needed for QEC.

3. Trapped ion

Trapped-ion quantum computers hold charged particles in an electromagnetic field. The confined particles serve as qubits, which the trapped-ion machines control using lasers. The lasers implement quantum gates, which create properties such as superposition and entanglement.

An important advantage of the trapped-ion modality is that qubits can maintain quantum states -- such as superposition and entanglement -- for longer periods compared with other methods. This longer coherence time lets quantum machines run complex algorithms. Another plus: Trapped-ion computers don't require dilution refrigeration, relying instead on cheaper laser-based cooling.

On the other hand, trapped-ion computers are generally slower than other types of quantum computing. When comparing trapped-ion and superconducting modalities, for example, a key tradeoff is longevity vs. speed.

"Ion-trap qubits live for a long time, but they are quite slow," said Michael Biercuk, founder and CEO of Q-CTRL, a quantum software infrastructure company that has worked with multiple modalities. "Superconducting qubits are very fast, but their so-called lifetime is short."

Technology companies pursuing the trapped-ion modality include Alpine Quantum Technologies, IonQ and Quantinuum.

4. Neutral atom

Neutral-atom quantum computers use atoms with a net electrical charge of zero as the foundation for qubits. This method uses lasers to trap atoms and manipulate the quantum states of qubits.

One advantage of neutral-atom technology is its scalability potential. The qubits' neutrality minimizes interference between them, which makes scaling qubits "relatively straightforward," according to a McKinsey & Co. report. This method can also operate at room temperature, using lasers to cool the qubits. However, the McKinsey report noted that scaling neutral-atom computers beyond certain thresholds could prove challenging.

Technology providers using this modality include Atom Computing, Pasqal and QuEra.

5. Photonic

This quantum computing method relies on the quantum properties of light, such as polarization, and employs photons as qubits to perform computations. Machines of this kind use mechanisms such as beam splitters and phase shifters to implement quantum gates.

This modality's advantages include speed and the ability to operate without a complex cooling system. Disadvantages include photon loss, which hinders performance.

Technology companies in the photonic market include Orca Computing, PsiQuantum, Quandela, Quix Quantum and Xanadu.

6. Quantum dots

This method uses nanoscale semiconductor crystals called quantum dots. Quantum dots confine charge-carrying particles, such as electrons, which serve as qubits. Machines using this modality manipulate the spin state of qubits to implement gates, which enable computation.

As for advantages, quantum dots' semiconductor connection means technology providers could tap classical manufacturing approaches to build "spin qubit chips," the McKinsey report stated. A challenge facing this method is a spin qubit's small size, which requires precise control electronics, the report noted. In addition, quantum dots generally require cryogenic cooling systems, but other mechanisms have been proposed.

Companies pursuing this modularity include Diraq, Quantum Motion and Quobly.

Recent developments: Topological qubits

Microsoft's February 2025 introduction of its Majorana 1 quantum processing unit focused attention on topological qubits as an emerging modality.

This approach is based on topological superconductivity, which Microsoft described as a new state of matter. Microsoft said the development stems from the fabrication of devices that merge a semiconductor, indium arsenide, with a superconductor, aluminum.

Critics have questioned the reliability of Microsoft's claims. However, skepticism regarding developments in the quantum field is not new or unusual.

That said, Anders Indset, founder and chairman of Njordis Group, noted Majorana could signal Microsoft's rise in quantum computing. Njordis, based in Oslo, Norway, is an investment and advisory company that focuses on quantum technologies, among other areas.

"If the Microsoft breakthrough actually manifests into a practical, not a theoretical, breakthrough, that's an approach that is very promising for the field," he said.

Indset said Microsoft has spent years heavily investing in the topological approach.

Indeed, Microsoft physicists discussed topological matter and the Majorana approach with company CEO Satya Nadella at the 2017 Microsoft Ignite conference. A year later, Microsoft-backed researchers published a paper on Majorana, which was retracted in 2021.

Microsoft, however, reasserted its case in research published in the February 2025 issue of Nature. The paper demonstrates the ability to engineer "a radically different type of qubit," Microsoft stated.

Which modality will prevail?

Multiple modalities complicate quantum computing for investors and prospective users. Other branches of computing have consolidated over time, which might happen with quantum as well. But in the near term, vendors will provide several paths to quantum advantage.

"If we look at history, it tells us that there will be generally one that's selected as the way, the preferred device, simply for the economies of scale," said Carl Dukatz, global lead of the quantum program at Accenture.

I am not a quantum physicist, and even my quantum physicist friends are having a hard time agree[ing] on the approaches that will be the winners.

But quantum technology plays out a bit differently. Dukatz likened quantum machines to a series of boxes into which technologists attempt to fit problems.

"The boxes have different lengths, widths and heights," he said. "Are we going to find a box that's an average, that does most everything? Or are we going to wind up with different sizes and nonstandardized shipping containers for problems? It's really yet to be seen."

Quantum investors and technology providers also expressed quantum uncertainty.

"I am not a quantum physicist, and even my quantum physicist friends are having a hard time agree[ing] on the approaches that will be the winners," Indset said.

Q-CTRL's Biercuk said his quantum infrastructure software company has worked with every quantum modality available and most hardware vendors.

"Each modality has its own strengths and weaknesses," he said. "We don't have a favorite."

John Moore is a writer for Informa TechTarget covering the CIO role, economic trends and the IT services industry.