PsiQuantum is focused on a singular mission: to construct the world’s first commercially useful, fault-tolerant quantum computer. Instead of pursuing incremental steps with smaller, near-term devices, the company has directed its resources toward the end-game of a large-scale machine from its inception.
The company’s strategy is built upon using a different medium for its quantum bits than more widely publicized methods like superconducting circuits or trapped-ion systems. This approach is based on a long-term vision for scalability and error correction, which it views as prerequisites for solving practical problems.
The Photonic Approach to Quantum Computing
PsiQuantum’s technology uses photons, individual particles of light, as its quantum bits, or “qubits.” This method, known as photonic quantum computing, contrasts with competitors like Google and IBM, which use superconducting circuits, or IonQ, which uses trapped ions. Those methods rely on controlling matter at the atomic level, whereas PsiQuantum’s approach centers on controlling light.
Information is encoded onto a photon’s physical properties. For instance, a qubit’s value of “0” or “1” can be represented by which of two optical fiber pathways a photon travels down. This is conceptually similar to how a traditional computer bit uses an electrical charge. By guiding photons through a network of microscopic channels and mirrors on a silicon chip, their quantum states are manipulated to execute complex calculations.
The process begins with generating single photons and guiding them onto custom-designed silicon chips. These chips contain an intricate architecture of tiny mirrors and pathways that influence the photons’ states and cause them to interact in specific ways. Specialized sensors detect the photons at the end of their journey, allowing the system to read the computation’s output. This entire framework forms the basis of what PsiQuantum calls fusion-based quantum computing, an architecture designed to be scalable.
Managing individual photons with the required precision is a demanding engineering task. Photons travel at the speed of light and can be easily lost, which historically made this approach seem impractical. PsiQuantum asserts it has developed techniques to overcome these difficulties, creating the hardware to generate, guide, and detect these light particles with high fidelity.
Advantages of Using Light for Computation
One primary advantage of using photons is the operational temperature. Photonic qubits do not require the extreme cold that superconducting qubits do. While some components in PsiQuantum’s system, like its detectors, need cryogenic cooling, they operate at much warmer temperatures than the near-absolute-zero conditions required by many competing technologies. This reduces the reliance on massive and costly dilution refrigerators, simplifying the system architecture.
Photons also interact weakly with their surrounding environment. In quantum computing, unwanted interaction with the outside world, or “decoherence,” is a primary source of errors. Because photons are less susceptible to this environmental noise, they can maintain their quantum state for longer, leading to lower error rates and contributing to a more reliable system.
Light is also well-suited for networking, as photons are already used to carry data through fiber-optic cables. PsiQuantum leverages this principle to connect different parts of its quantum computer. This allows for a modular design where thousands of quantum chips can be linked together to create a single, powerful processor, a task that is more challenging for matter-based qubit systems.
Manufacturing and Scaling Strategy
A central element of PsiQuantum’s strategy is its partnership with semiconductor manufacturer GlobalFoundries. This collaboration allows PsiQuantum to use existing silicon photonics manufacturing facilities, or “fabs,” to produce its quantum chips. These are the same types of industrial facilities that produce components for the telecommunications and data center industries.
This manufacturing-first approach means the company designs its chips for fabrication in standard, high-volume processes. The partners have installed proprietary equipment within GlobalFoundries’ fabs to produce the specialized photonic and electronic control chips required for the system. This gives PsiQuantum a direct path to producing the millions of components needed for a utility-scale machine.
The company’s goal is to build a fault-tolerant quantum computer with at least one million physical qubits. A fault-tolerant system can perform reliable computations despite the fragile nature of its qubits. This is achieved through quantum error correction, where information is encoded across many physical qubits to create a single, stable “logical qubit.” By combining its photonic architecture with a scalable manufacturing process, PsiQuantum aims to be the first to reach this threshold.
Current Status and Future Outlook
PsiQuantum has made steady progress through substantial funding and strategic partnerships. The company has attracted significant investment to pursue its long-term goals. A notable development is its collaboration with the UK government, which provided £9 million in funding to establish an advanced research and development facility at Daresbury Laboratory. This site gives PsiQuantum access to large-scale cryogenic plants and expertise in the cooling systems needed for its machines.
While often operating in a less public-facing manner than some competitors, the company has released information about its technical milestones. It has announced the development of its Omega chipset, a manufacturable platform that integrates all the necessary components for a scalable photonic quantum computer. This includes high-performance single-photon sources and detectors fabricated at GlobalFoundries. The company has reported high fidelity rates for its qubit operations and has demonstrated the ability to connect chips over long distances.
PsiQuantum is preparing to transition from research and development to deployment. The company has announced plans for Quantum Compute Centers in Brisbane, Australia, and Chicago, Illinois, to house its first utility-scale systems. These datacenter-sized facilities signal a move toward industrial-scale quantum computing. Once operational, these machines are intended to tackle complex problems in fields such as drug discovery, materials science, finance, and climate science.