It is a law of physics that everything that is not prohibited is mandatory. Errors are thus unavoidable. They are everywhere: in language, cooking, communication, image processing and, of course, computation. Mitigating and correcting them keeps society running. You can scratch a DVD yet still play it. QR codes can be blurred or torn yet are still readable. Images from space probes can travel hundreds of millions of miles yet still look crisp. Error correction is one of the most fundamental concepts in information technology. Errors may be inevitable, but they are also fixable.
This law of inevitability applies equally to quantum computers. These emerging machines exploit the fundamental rules of physics to solve problems that classical computers find intractable. The implications for science and business could be profound. But with great power comes great vulnerability. Quantum computers suffer types of errors that are unknown to classical computers and that our standard correction techniques cannot fix.
I am a physicist working in quantum computing at IBM, but my career didn’t start there. I began as a condensed-matter theorist investigating materials’ quantum-mechanical behavior, such as superconductivity; at the time I was oblivious to how that would eventually lead me to quantum computation. That came later when I took a hiatus to work on science policy at the U.S. Department of State, which next led me to the Defense Advanced Research Projects Agency (DARPA) and the Intelligence Advanced Research Projects Activity (IARPA). There I sought to employ the fundamentals of nature to develop new technology.
Quantum computers were in their earliest stages then. Although Paul Benioff of Argonne National Laboratories had proposed them in 1980, it took physicists nearly two decades to build the first one. Another decade later, in 2007, they invented the basic data unit that underlies the quantum computers of IBM, Google and others, known as the superconducting transmon qubit. My experience with superconductivity was suddenly in demand. I helped run several quantum-computing research programs at IARPA and later joined IBM.
To read more, click here.