She moved to the United Kingdom for her graduate research, where she worked toward her doctorate in materials science at the University of Oxford.

[5][6] She was part of the UNSW team who first demonstrated quantum logic between two electrons in a silicon chip.

[5][7] Using a conventional semiconductor manufacturing process, Simmons worked on a controlled-not gate (CNOT) that makes use of electron spin to store quantum information.

[8] Simmons joined the faculty at Simon Fraser University in 2015, where she leads the Silicon Quantum Technology laboratory.

[9][10] She was named a Canada Research Chair in 2017, and concentrated her efforts on the development of the world's first quantum computer.