In the previous episodes (check here), we explored how to precisely arrange and control individual atoms, including charged ones, holding them in place with remarkable accuracy. We also looked at how single atoms and ions can serve as the foundation for state-of-the-art quantum computers, along with the challenges these approaches face. Since it’s still unclear which platform will ultimately prevail, it’s worth investigating alternative systems for building quantum computers.

Interestingly, qubits can also be created using tiny electrical circuits. Major companies like IBM and Google are actively pursuing this approach, racing to develop scalable quantum machines based on such technology.

So how do we turn electrical circuits into qubits, the fundamental building blocks of quantum computers?

Welcome to the world of superconducting qubits.

At first glance, this approach feels almost backwards. Instead of isolating a single atom, researchers build tiny electrical circuits on a chip—using metals and insulators, much like the ones inside your phone.

But what exactly is a circuit?

In simple terms, a circuit is a path that allows electricity to flow—like a loop of tiny roads that electric charges can travel through. It usually includes elements that guide and control this flow, such as wires, resistors, or capacitors. Here is an example circuit:

But here’s the twist:

Under the right conditions, these circuits stop behaving like ordinary electronics and start behaving like quantum systems.

They become artificial atoms!