Why quantum chip anatomy matters

How the layout of a quantum processing unit (QPU) influences quantum software compilation

If you’re not a Medium member, you can read the complete article for free on Substack or on this page.

A quantum processing unit (QPU), also called a quantum chip, is the brain of the quantum computer.

It is where qubits, the fundamental unit of a quantum computer, reside, and where computation takes place. It is the quantum equivalent of a central processing unit (CPU) in everyday classical computers such as smartphones, laptops, and servers.

When companies refer to developing a “better” quantum computer, they often mean competing on a better QPU, on finding the optimal physical method to build qubits (also known as modality), and qubit layout.

In a classical computer, the layout of a CPU impacts its speed and energy consumption.

The arrangement of qubits in a QPU affects speed differently. Because of the unique properties of qubits, certain layouts of a QPU require more code adjustments to quantum circuits, or software programs running on quantum computers, to successfully compile and execute them.

In this article, we compare the layouts of QPUs using superconducting and trapped-ion…