PrincetonEngineers

Quantum information is exceptionally fragile. Defects or impurities in materials can lead to decoherence, the process by which quantum information is destroyed. In order to make better qubits, we need to find better materials. This is a big part of my research at Princeton. Working with Nathalie de Leon and Bob Cava, we are trying to figure out what metals, substrates, oxides, etc are the leading causes of loss in superconducting qubits, and how to make them better. This is also a major research thrust as part of our DOE National Quantum Initiative Center (the Co-Design Center for Quantum Advantage).

Defects in diamond are a useful platform for quantum networking and quantum sensing, but there are an enormous number of defects (helpfully cataloged by De Beers). Trying to design and grow new diamonds for quantum purposes is another major effort here on campus, in conjunction with the Princeton Plasma Physics Lab.

There are other long term materials questions that could impact quantum as well. Scientists have speculated that an elusive state known as a Majorana fermion could encode quantum information in a way that is naturally robust against noise. Scientists like Ali Yazdani and Phuan Ong at Princeton are trying to find new materials that actually realize these particles as a new avenue for quantum computing.

It’s hard to quantify, but on a scale of one to ten, I’d say at least a 007.

Definitely not (that’s the kind of answer that could come back to haunt me in twenty years).  Quantum computers can do anything that classical computers can do, but they’ll almost assuredly be slower and costlier than their classical counterparts at running applications/algorithms that don’t have a large amount of quantum speedup.

Also, we are in an era where you don’t actually see or touch most of the classical computing you use – your phone or laptop just needs to be fast enough to connect to all of the data centers around the world. Once we have quantum computers, those will be no different.

The two coolest outcomes would be to do literally anything practical on a quantum computer, or to discover some fundamental reason why quantum computers fail that completely changes our perspective on the world.

We don’t actually know what the first practically accessible quantum algorithm would be. I could probably speculate that it would be something related to simulating chemistry, possibly catalysis.

Tom Wong (currently at White House Office of Science and Technology Policy) has a great free(!) book on quantum computing available on his website: https://www.thomaswong.net/