Home Computing What’s a Qubit? 3 Ways Scientists Build Quantum Computers

What’s a Qubit? 3 Ways Scientists Build Quantum Computers

by Amelia Ramiro

Quantum computers have long been hailed as the future of technology, with the potential to revolutionize industries such as pharmaceuticals and logistics. However, despite the hype, no quantum computer has reached the point of “quantum advantage,” where it can solve problems that classical computers cannot.

The key to quantum computing lies in the qubit, the quantum equivalent of a classical transistor. Qubits have the ability to exist in multiple states at the same time, known as superposition, and can be entangled with one another, allowing for complex computations. Scientists are experimenting with various materials to create qubits, including superconducting qubits, trapped-ion qubits, and neutral-atom qubits.

Superconducting qubits, favored by companies like Google and IBM, are made of aluminum or a mix of aluminum and niobium. They can be manufactured using existing technologies and are relatively small and inexpensive. However, they require cooling to extremely low temperatures and the hardware needed to operate them is costly. Currently, only tens to hundreds of superconducting qubits can be supported in a dilution refrigerator, but plans are underway to scale to thousands.

Trapped-ion qubits, used by companies like IonQ and Quantinuum, are charged atoms or molecules that behave like tiny bar magnets. They can retain quantum information for a longer time compared to superconducting qubits, but computations on this system take longer. Scaling trapped-ion qubit computers is challenging, as interactions among the qubits become more complex. To reach millions of qubits, ions will need to be moved between modules, a feat that has not yet been reliably achieved.

Neutral-atom qubits, created by shining lasers through a lens to trap neutral atoms, offer better scalability than trapped-ion qubits. Arrays of up to 1,000 neutral-atom qubits have been created, and researchers believe that the number could be increased to 10,000 or more with advancements in technology. However, neutral-atom qubits are slower than superconducting qubits, and researchers have yet to efficiently operate more than a handful of them.

Despite the challenges, scientists remain optimistic about the potential of quantum computing. As the search for the best types of qubits continues, it is only a matter of time before quantum computers reach the point of quantum advantage. Once this happens, the world could see a true revolution in computing power and capabilities.

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