Measurement-induced entanglement and teleportation on a noisy quantum processor
Authors:   Google Quantum AI and Collaborators, Hoke J. C. , Ippoliti M. , Rosenberg E. , Abanin D. , Acharya R. , Andersen T. I. , Ansmann M. , Arute F. , Arya K. , Asfaw A. , Atalaya J. , Bardin J. C. , Bengtsson A. , Bortoli G. , Bourassa A. , Bovaird J. , Brill L. , Broughton M. , Buckley B. B. , Buell D. A. , Burger T. , Burkett B. , Bushnell N. , Chen Z. , Chiaro B. , Chik D. , Cogan J. , Collins R. , Conner P. , Courtney W. , Crook A. L. , Curtin B. , Dau A. G. , Debroy D. M. , Del Toro Barba A. , Demura S. , Di Paolo A. , Drozdov I. K. , Dunsworth A. , Eppens D. , Erickson C. , Farhi E. , Fatemi R. , Ferreira V. S. , Burgos L. F. , Forati E. , Fowler A. G. , Foxen B. , Giang W. , Gidney C. , Gilboa D. , Giustina M. , Gosula R. , Gross J. A. , Habegger S. , Hamilton M. C. , Hansen M. , Harrigan M. P. , Harrington S. D. , Heu P. , Hoffmann M. R. , Hong S. , Huang T. , Huff A. , Huggins W. J. , Isakov S. V. , Iveland J. , Jeffrey E. , Jiang Z. , Jones C. , Juhas P. , Kafri D. , Kechedzhi K. , Khattar T. , Khezri M. , Kieferová M. , Kim S. , Kitaev A. , Klimov P. V. , Klots A. R. , Korotkov A. N. , Kostritsa F. , Kreikebaum J. M. , Landhuis D. , Laptev P. , Lau K.-M. , Laws L. , Lee J. , Lee K. W. , Lensky Y. D. , Lester B. J. , Lill A. T. , Liu W. , Locharla A. , Martin O. , McClean J. R. , McEwen M. , Miao K. C. , Mieszala A. , Montazeri S. , Morvan A. , Movassagh R. , Mruczkiewicz W. , Neeley M. , Neill C. , Nersisyan A. , Newman M. , Ng J. H. , Nguyen A. , Nguyen M. , Niu M. Y. , O’Brien T. E. , Omonije S. , Opremcak A. , Petukhov A. , Potter R. , Pryadko L. P. , Quintana C. , Rocque C. , Rubin N. C. , Saei N. , Sank D. , Sankaragomathi K. , Satzinger K. J. , Schurkus H. F. , Schuster C. , Shearn M. J. , Shorter A. , Shutty N. , Shvarts V. , Skruzny J. , Smith W. C. , Somma R. , Sterling G. , Strain D. , Szalay M. , Torres A. , Vidal G. , Villalonga B. , Heidweiller C. V. , White T. , Woo B. W. K. , Xing C. , Yao Z. J. , Yeh P. , Yoo J. , Young G. , Zalcman A. , Zhang Y. , Zhu N. , Zobrist N. , Neven H. , Babbush R. , Bacon D. , Boixo S. , Hilton J. , Lucero E. , Megrant A. , Kelly J. , Chen Y. , Smelyanskiy V. , Mi X. , Khemani V. , Roushan P. 
Published: October 2023

AbstractMeasurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the ‘arrow of time’ that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space–time3–10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11–13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15–17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,4 to measurement-induced teleportation18. We obtain finite-sized signatures of a phase transition with a decoding protocol that correlates the experimental measurement with classical simulation data. The phases display remarkably different sensitivity to noise, and we use this disparity to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realizing measurement-induced physics at scales that are at the limits of current NISQ processors.