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arXiv · 2106.05881

Observation of measurement-induced quantum phases in a trapped-ion quantum computer

Crystal Noel·Pradeep Niroula·Daiwei Zhu·Andrew Risinger·Laird Egan·Debopriyo Biswas·Marko Cetina·Alexey V. Gorshkov·Michael J. Gullans·David A. Huse·Christopher Monroe
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Abstract

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.

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Crystal Noel, Pradeep Niroula, Daiwei Zhu, Andrew Risinger, Laird Egan, Debopriyo Biswas, Marko Cetina, Alexey V. Gorshkov, Michael J. Gullans, David A. Huse, Christopher Monroe. 2021-06-10. Observation of measurement-induced quantum phases in a trapped-ion quantum computer. https://doi.org/10.1038/s41567-022-01619-7

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