The idea here is plug n' play: how can one quantum computer call upon another to perform a subroutine - without assuming anything about how the second computer was physical constructed? This becomes a very important question as the world builds towards scalable quantum computing - where two different parties wishes to work together to conduct a single computation; but want to do so in a way that they don't have to assume anything about each other's laboratory.
In this article, we built a full framework for understanding when plug n' play is possible. Along the way, we discovered two protocols. Black-Box DQC1 that can find the |Tr(U)| or a completely unknown unitary, and Black-box factoring that uses significantly fewer entangling gates by recycling part of its circuit.
- Quantum plug n' play: modular computation in the quantum regime -
Jayne Thompson, Kavan Modi, Vlatko Vedral and Mile Gu
