From The Conversation By Muhammad Usman Head of Quantum Systems and Principal Research Scientist, CSIRO In recent years, the field of quantum computing has been experiencing fast growth, with technological advances and large-scale investments regularly making the news. The United Nations has designated 2025 as the International Year of Quantum Science and Technology.
thequantuminsider.com/, Jan. 08, 2025 –
The stakes are high – having quantum computers would mean access to tremendous data processing power compared to what we have today. They won't replace your normal computer, but having this kind of awesome computing power will provide advances in medicine, chemistry, materials science and other fields.
So it's no surprise that quantum computing is rapidly becoming a global race, and private industry and governments around the world are rushing to build the world's first full-scale quantum computer. To achieve this, first we need to have stable and scalable quantum processors, or chips.
What is a quantum chip?
Everyday computers – like your laptop – are classical computers. They store and process information in the form of binary numbers or bits. A single bit can represent either 0 or 1.
By contrast, the basic unit of a quantum chip is a qubit. A quantum chip is made up of many qubits. These are typically subatomic particles such as electrons or photons, controlled and manipulated by specially designed electric and magnetic fields (known as control signals).
Unlike a bit, a qubit can be placed in a state of 0, 1, or a combination of both, also known as a "superposition state". This distinct property allows quantum processors to store and process extremely large data sets exponentially faster than even the most powerful classical computer.
There are different ways to make qubits – one can use superconducting devices, semiconductors, photonics (light) or other approaches. Each method has its advantages and drawbacks.
Companies like IBM, Google and QueRa all have roadmaps to drastically scale up quantum processors by 2030.
Industry players that use semiconductors are Intel and Australian companies like Diraq and SQC. Key photonic quantum computer developers include PsiQuantum and Xanadu.
Qubits: quality versus quantity
How many qubits a quantum chip has is actually less important than the quality of the qubits.
A quantum chip made up of thousands of low-quality qubits will be unable to perform any useful computational task.
So, what makes for a quality qubit?
Qubits are very sensitive to unwanted disturbances, also known as errors or noise. This noise can come from many sources, including imperfections in the manufacturing process, control signal issues, changes in temperature, or even just an interaction with the qubit's environment.
Being prone to errors reduces the reliability of a qubit, known as fidelity. For a quantum chip to stay stable long enough to perform complex computational tasks, it needs high-fidelity qubits.
When researchers compare the performance of different quantum chips, qubit fidelity is one of the crucial parameters they use.
How do we correct the errors?
Fortunately, we don't have to build perfect qubits.
Over the last 30 years,