The New Quantum Era

Chapter 8. Experimentalists Just Wanna Have Fun

No one doubts that building a useful quantum computer (one capable of addressing challenging computational problems) is difficult, but is it actually impossible? Do fundamental physical principles pose a truly serious obstacle?

John Preskill

The foundations of quantum computing were built by theorists’ equations, from Wiesner, Deutsch, Shor, and the rest. Now that it had been established that universal quantum computing was theoretically possible, and that it could do certain things much faster than classical computers, attention began to shift to the experimentalists working in their labs with lasers, liquid helium, and other hazardous materials. The fact that Shor had attracted the attention of certain government agencies, who now wanted to know who could build a machine to run the algorithm and how much it would cost, was only to their advantage. The public funding sluices opened up, and anyone with a reasonable idea about how one might build a qubit found themselves flush with budget to pay students and postdocs and buy all kinds of equipment and components.

The theorists had begun working toward realizing physical quantum bits by describing them in the abstract, with quantum mechanical terms. All the experimentalists needed to do was to identify quantum systems that could fulfill those characteristics, and away they’d go. Specifically, the system had to have two or more distinct states measurable in attributes such as spin, ...