@article{84cca8efcfa14c769632e9207a6f802a,
title = "Measurement-induced quantum phases realized in a trapped-ion quantum computer",
abstract = "Many-body open quantum systems balance internal dynamics against decoherence and measurements induced by interactions with an environment1,2. Quantum circuits composed of random unitary gates with interspersed projective measurements represent a minimal model to study the balance between unitary dynamics and measurement processes3–5. As the measurement rate is varied, a purification phase transition is predicted to emerge at a critical point akin to a fault-tolerant threshold6. Here we explore this purification transition with random quantum circuits implemented on a trapped-ion quantum computer. We probe the pure phase, where the system is rapidly projected to a pure 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 that keeps the memory of initial conditions for long times6,7. We find experimental evidence of the two phases and show numerically that, with modest system scaling, critical properties of the transition emerge.",
author = "Crystal Noel and Pradeep Niroula and Daiwei Zhu and Andrew Risinger and Laird Egan and Debopriyo Biswas and Marko Cetina and Gorshkov, {Alexey V.} and Gullans, {Michael J.} and Huse, {David A.} and Christopher Monroe",
note = "Funding Information: We acknowledge fruitful discussions with E. Altman, S. Choi, A. Deshpande, S. Diehl, B. Fefferman, S. Gopalakrishnan, M. Ippoliti, V. Khemani, A. Nahum, J. Pixley, O. Shtanko and A. Zabalo, and the contributions of M. Goldman, K. Beck, J. Amini, K. Hudek and J. Mizrahi to the experimental set-up. This work is supported by the ARO through the IARPA LogiQ programme, the NSF STAQ programme, the AFOSR MURIs on Dissipation Engineering in Open Quantum Systems and Quantum Measurement/Verification and Quantum Interactive Protocols, the ARO MURI on Modular Quantum Circuits, the DoE Quantum Systems Accelerator, the DoE ASCR Accelerated Research in Quantum Computing programme (award no. DE-SC0020312) and the National Science Foundation (QLCI grant no. OMA-2120757). L.E. is also funded by NSF award no. DMR-1747426. This work was performed at the University of Maryland with no material support from IonQ. Funding Information: We acknowledge fruitful discussions with E. Altman, S. Choi, A. Deshpande, S. Diehl, B. Fefferman, S. Gopalakrishnan, M. Ippoliti, V. Khemani, A. Nahum, J. Pixley, O. Shtanko and A. Zabalo, and the contributions of M. Goldman, K. Beck, J. Amini, K. Hudek and J. Mizrahi to the experimental set-up. This work is supported by the ARO through the IARPA LogiQ programme, the NSF STAQ programme, the AFOSR MURIs on Dissipation Engineering in Open Quantum Systems and Quantum Measurement/Verification and Quantum Interactive Protocols, the ARO MURI on Modular Quantum Circuits, the DoE Quantum Systems Accelerator, the DoE ASCR Accelerated Research in Quantum Computing programme (award no. DE-SC0020312) and the National Science Foundation (QLCI grant no. OMA-2120757). L.E. is also funded by NSF award no. DMR-1747426. This work was performed at the University of Maryland with no material support from IonQ. Publisher Copyright: {\textcopyright} 2022, The Author(s), under exclusive licence to Springer Nature Limited.",
year = "2022",
month = jul,
doi = "10.1038/s41567-022-01619-7",
language = "English (US)",
volume = "18",
pages = "760--764",
journal = "Nature Physics",
issn = "1745-2473",
publisher = "Nature Publishing Group",
number = "7",
}