What is a quantum chip and why do we need it?

Microsoft has one. Google and IBM also have one. And several smaller companies, including Copenhagen-based Sparrow Quantum, have one too. The quantum chip. Each of these companies has developed its own version of the small piece of hardware needed for quantum technology.

"The quantum chip is the platform that enables us to utilise quantum mechanics for calculations, information processing, encryption, or to perform ultra-precise measurements in the field of quantum sensing, among other things. In other words: no quantum chips, no quantum technologies ," says Maria Cerdà Sevilla, head of Quantum DTU.

Bits versus quantum bits

In the classic microchip found in all our modern electronics, such as computers and mobile phones, the information-carrying units are called bits. They are created using transistors, which are small switches that turn the power on and off. On gives 1 and off gives 0.

In quantum chips, the information-carrying units are called quantum bits or qubits. Qubits can be created in several ways. All you need is a physical system that can be in two states, that you are able to control. Around the world, different physical systems are being explored as candidates for realizing qubits, such as atoms, ions, photons or electrons in superconducting materials. What they all have in common is that they have quantum mechanical properties that can be exploited.

1 and 0 simultaneously

One of these properties is superposition. This is a physical principle which means that the qubit can assume the states 1 and 0 at the same time. This increases the number of possible calculations exponentially for each qubit in the system. This is precisely why there are expectations that the quantum computer will be an extremely powerful computer.

In the podcast Mikroskop from Novo Nordisk Foundation, Lene Oddershede, Professor and Senior Vice President, Planetary Science & Technology, Novo Nordisk Foundation, explains the potential of quantum computers as follows:

“Imagine a maze with 1,000 blind paths, and only one path that leads you through. A modern computer can try one path at a time, while a quantum computer can try all paths at once, thus finding the way through at lightning speed.”

Still at an early stage

Although the quantum chip exists, the technology is still very immature, according to Maria Cerdà Sevilla:

"We are still at the stage where quantum technologies are mostly found in laboratories. Although they are constantly maturing, we still have a long way to go before we achieve the perfect quantum chip. There is still a lot of work to be done to find the perfect chip design, increase the number of qubits on each chip and connect the chip to the systems it will be part of."