Here’s how the IBM Q System One works while keeping its qubits colder than outer space
- Ask a question Using a conventional laptop as an interface, enter the problem you want to solve. Keep it simple, as today’s system can’t run many operations and stay cool.
- Microwave electronics Electronics convert your query from ones and zeroes into microwave pulses, which are carried thorough wires to the computer.
- Input microwave lines As the microwave pulses enter the system their signals are reduced, so their heat doesn’t affect the qubits.
- Multistage refrigerator Two helium isotopes are mixed together in such a way that they create a reaction that absorbs heat, chilling the whole system down to -273.135°C.
- Qubit processor The qubit chips – also known as ‘transmons’ – are stored just below the helium mixing chamber. Extra shielding also protects them from electromagnetic radiation
- Quantum calculation The microwave pulses manipulate the qubits, adding or subtracting them from one another to generate an answer
- Amplifying the answer Readout measurements from the qubits are routed through circulators. Amplifiers boost their signal.
- Digital conversion The bank of electronics digitizes these measurement signals and an answer is sent back to the laptop.
- Double-check This whole process takes a matter of seconds but may need to be done several times as quantum computers have such a high error rate
How significant is Google’s breakthrough?
It’s a technical next step, but it’s not necessarily as significant as some people think. What Google has done is solved an academic problem – one that is entirely useless in a practical sense. It’s a problem that’s chosen with one thing in mind: whether a quantum computer can do something a conventional computer can’t.
So why are we talking about it?
Google’s achievement demonstrates that quantum computers are not like nuclear fusion, which a lot of people often say is ten years away, but never actually arrives. When I started 20 years ago, people were very skeptical. Most of my colleagues rolled their eyes at me when I said I was going to build a quantum computer. That’s because it’s unbelievably hard to control the quantum effects of atoms. So what Google has achieved is still really nice, as it’s demonstrated mastery of manipulating 53 qubits. That’s a big milestone.
When do you think quantum computing will come into its own?
Quantum computing will likely follow the same development path as conventional computers. In the 1940s, conventional computers decided World War II by breaking the German Enigma code. However, while they were good for a particular task, they couldn’t tell you train times, handle word processing or play video games. It was another 40 to 50 years until we used them for literally everything. It’s a gradual process. Quantum computers now are probably approaching those in the 1940s. In the next five years, these machines will be able to solve one particular practical problem.