Quantum computers promise to solve problems that are beyond the reach of ordinary computers. But their components, quantum bits, are very sensitive. One type of quantum bit is an oscillating circuit that can exist in two states, like a pendulum swinging left or right. These states store information.
However, when several such bits operate side by side, they start to influence each other. It's like two pendulums hanging from the same wall: the oscillations of one transfer to the other and throw off its rhythm. As a result, a bit might randomly jump from one state to another, and information is lost.
The researchers proposed several ways to reduce interference: tune the oscillation frequencies so they don't match, change the signal strength, or weaken the coupling between bits. This is like moving pendulums farther apart or making them swing at different speeds so they don't interfere with each other.
Now engineers have concrete recipes for building quantum computers with many such bits without losing information due to mutual interference.
The time a quantum bit retains information can decrease by a factor of ten if another identical bit operates nearby.
The problem of mutual interference between quantum bits echoes the challenges in Hannu Rajaniemi's novel 'The Quantum Thief,' where quantum systems constantly struggle with decoherence.