Getting Physical

The non-physicist finds it hard to believe that really the ordinary laws of physics, which he regards as the prototype of inviolable precision, should be based on the statistical tendency of matter to go over into disorder

Erwin Schrödinger

It’s time to discuss some considerations about how we go from theoretical mathematics and physics to the applied and experimental.

The qubits we make and use in the lab for research and those we will deploy for commercial applications involve physical hardware devices such as photonic and microwave controllers. They are subject to noise from the environment, their electronic components, and artifacts from manufacturing choices. Hardware improvements decrease the disturbances, but software and system ones can too. The long-term goal is to have fully fault-tolerant, error-corrected quantum computing devices.

This chapter concludes with a discussion of light and photons to illustrate how properties like...