Edward Farhi, The Physicist Behind QAOA

Edward Farhi invented two of the most-studied algorithms in quantum computing, both aimed at the same target, optimisation, which is also the application the industry most often promises. He built the quantum adiabatic algorithm in 2000 and the quantum approximate optimisation algorithm, QAOA, in 2014, and between them they have shaped how the field thinks about solving hard combinatorial problems. What makes Farhi the right person to profile is not just that he built these tools, but that he has been among the clearest voices on their limits. He came to quantum computing after a full career in particle physics, and he brought with him a physicist’s insistence on knowing exactly what has been proved and what has merely been hoped. On the question the whole field turns on, whether quantum optimisation actually beats the best classical methods, the inventor of the leading algorithm is notably careful. Farhi built two landmark quantum algorithms. The quantum adiabatic algorithm in 2000 and QAOA in 2014, both aimed at approximate optimisation, the application quantum computing most often promises. He came from particle physics. As a student he introduced thrust as a QCD observable, a variable still used at the Large Hadron Collider, and…