Irfan Siddiqi

An orchestra plays inside a giant refrigerator. The musicians are qubits, the elementary cells of a quantum computer. To play in harmony, they need silence: thermal noise drowns out the melody. That's why the heart of a quantum processor is cooled to nearly absolute zero — minus 273 degrees Celsius.

A quantum bit, or qubit, is like a coin spinning on a table, able to be both heads and tails at once. For the computer to know what came up, you have to stop the coin and look. Previously, this stopping was done with a delay: data was read out, taken to a regular computer for processing, and only then was the result known.

An ordinary pendulum swings at the same frequency as the push it receives. But in the quantum world, you can create a system that responds to a push two, three, or more times slower, as if it has its own rhythm. Such systems are called discrete time crystals.