COMPUTER SCIENCE:
Randomness in Quantum Computation
Juan Pablo Paz
Introducing randomness by computationally flipping a coin can increase the efficiency of classical computer algorithms. Quantum computing may also benefit from the introduction of randomness, but doing so is less straightforward because at any step, a quantum computer can follow a continuous set of possible paths. In his Perspective, Paz explains that a good approximation of randomness can be introduced more easily than was anticipated. He highlights the report by Emerson et al., who have devised a two-step procedure that allows the efficient implementation of quantum coin-tosses in an approximate but useful way.
The author is in the Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. He is on leave from the Departamento de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires, Argentina. E-mail: jpaz{at}lanl.gov