Press the start button, switch on the monitor, grab a cup of coffee and off you go. That is pretty much how most us experience booting up a computer. But with a quantum computer the situation is very different. So far, researchers have had to spend hours making dozens of adjustments and fine calibrations in order to set up a chip with just five quantum bits so that it can be used for experimental work. (One quantum bit or "qubit" is the quantum physical equivalent of a single bit in a conventional computer). Any small errors in the adjustment and calibration procedure and the chip would not work.
The problem is that, not unlike musical instruments, quantum computers react to small changes in the local environment. If, for example, it is a little warmer or a little colder or if the ambient air pressure is a little higher or a little lower than the day before then the complex network of qubits will no longer function — the computer is detuned and has to be readjusted before it can be used. "Up until now, experimental quantum physicists have had to sit down each day and see how conditions have changed compared to the day before. They then had to remeasure each parameter and carefully recalibrate the chip," explains Prof. Wilhelm-Mauch, Professor for Theoretical Quantum and Solid-State Physics at Saarland University.