%0 Journal Article %D 2021 %T Observation of measurement-induced quantum phases in a trapped-ion quantum computer %A Crystal Noel %A Pradeep Niroula %A Daiwei Zhu %A Andrew Risinger %A Laird Egan %A Debopriyo Biswas %A Marko Cetina %A Alexey V. Gorshkov %A Michael Gullans %A David A. Huse %A Christopher Monroe %X

Many-body open quantum systems balance internal dynamics against decoherence from interactions with an environment. Here, we explore this balance via random quantum circuits implemented on a trapped ion quantum computer, where the system evolution is represented by unitary gates with interspersed projective measurements. As the measurement rate is varied, a purification phase transition is predicted to emerge at a critical point akin to a fault-tolerent threshold. We probe the "pure" phase, where the system is rapidly projected to a deterministic state conditioned on the measurement outcomes, and the "mixed" or "coding" phase, where the initial state becomes partially encoded into a quantum error correcting codespace. We find convincing evidence of the two phases and show numerically that, with modest system scaling, critical properties of the transition clearly emerge.

%8 6/10/2021 %G eng %U https://arxiv.org/abs/2106.05881