Constructive interference at the edge of quantum ergodic dynamics
Abstract
Quantum observables in the form of few-point correlators are the key to characterizing the dynamics of quantum many-body systems. In dynamics with fast entanglement generation, quantum observables generally become insensitive to the details of the underlying dynamics at long times due to the effects of scrambling. In experimental systems, repeated time-reversal protocols have been successfully implemented to restore sensitivities of quantum observables. Using a 103-qubit superconducting quantum processor, we characterize ergodic dynamics using the second-order out-of-time-order correlators, OTOC. In contrast to dynamics without time reversal, OTOC are observed to remain sensitive to the underlying dynamics at long time scales. Furthermore, by inserting Pauli operators during quantum evolution and randomizing the phases of Pauli strings in the Heisenberg picture, we observe substantial changes in OTOC values. This indicates that OTOC is dominated by constructive interference between Pauli strings that form large loops in configuration space. The observed interference mechanism endows OTOC with a high degree of classical simulation complexity, which culminates in a set of large-scale OTOC measurements exceeding the simulation capacity of known classical algorithms. Further supported by an example of Hamiltonian learning through OTOC, our results indicate a viable path to practical quantum advantage.
Cite
@article{arxiv.2506.10191,
title = {Constructive interference at the edge of quantum ergodic dynamics},
author = {Dmitry A. Abanin and Rajeev Acharya and Laleh Aghababaie-Beni and Georg Aigeldinger and Ashok Ajoy and Ross Alcaraz and Igor Aleiner and Trond I. Andersen and Markus Ansmann and Frank Arute and Kunal Arya and Abraham Asfaw and Nikita Astrakhantsev and Juan Atalaya and Ryan Babbush and Dave Bacon and Brian Ballard and Joseph C. Bardin and Christian Bengs and Andreas Bengtsson and Alexander Bilmes and Sergio Boixo and Gina Bortoli and Alexandre Bourassa and Jenna Bovaird and Dylan Bowers and Leon Brill and Michael Broughton and David A. Browne and Brett Buchea and Bob B. Buckley and David A. Buell and Tim Burger and Brian Burkett and Nicholas Bushnell and Anthony Cabrera and Juan Campero and Hung-Shen Chang and Yu Chen and Zijun Chen and Ben Chiaro and Liang-Ying Chih and Desmond Chik and Charina Chou and Jahan Claes and Agnetta Y. Cleland and Josh Cogan and Saul Cohen and Roberto Collins and Paul Conner and William Courtney and Alexander L. Crook and Ben Curtin and Sayan Das and Laura De Lorenzo and Dripto M. Debroy and Sean Demura and Michel Devoret and Agustin Di Paolo and Paul Donohoe and Ilya Drozdov and Andrew Dunsworth and Clint Earle and Alec Eickbusch and Aviv Moshe Elbag and Mahmoud Elzouka and Catherine Erickson and Lara Faoro and Edward Farhi and Vinicius S. Ferreira and Leslie Flores Burgos and Ebrahim Forati and Austin G. Fowler and Brooks Foxen and Suhas Ganjam and Gonzalo Garcia and Robert Gasca and Elie Genois and William Giang and Craig Gidney and Dar Gilboa and Raja Gosula and Alejandro Grajales Dau and Dietrich Graumann and Alex Greene and Jonathan A. Gross and Hanfeng Gu and Steve Habegger and John Hall and Ikko Hamamura and Michael C. Hamilton and Monica Hansen and Matthew P. Harrigan and Sean D. Harrington and Stephen Heslin and Paula Heu and Oscar Higgott and Gordon Hill and Jeremy Hilton and Sabrina Hong and Hsin-Yuan Huang and Ashley Huff and William J. Huggins and Lev B. Ioffe and Sergei V. Isakov and Justin Iveland and Evan Jeffrey and Zhang Jiang and Xiaoxuan Jin and Cody Jones and Stephen Jordan and Chaitali Joshi and Pavol Juhas and Andreas Kabel and Dvir Kafri and Hui Kang and Amir H. Karamlou and Kostyantyn Kechedzhi and Julian Kelly and Trupti Khaire and Tanuj Khattar and Mostafa Khezri and Seon Kim and Robbie King and Paul V. Klimov and Andrey R. Klots and Bryce Kobrin and Alexander N. Korotkov and Fedor Kostritsa and Robin Kothari and John Mark Kreikebaum and Vladislav D. Kurilovich and Elica Kyoseva and David Landhuis and Tiano Lange-Dei and Brandon W. Langley and Pavel Laptev and Kim-Ming Lau and Loick Le Guevel and Justin Ledford and Joonho Lee and Kenny Lee and Yuri D. Lensky and Shannon Leon and Brian J. Lester and Wing Yan Li and Alexander T. Lill and Wayne Liu and William P. Livingston and Aditya Locharla and Erik Lucero and Daniel Lundahl and Aaron Lunt and Sid Madhuk and Fionn D. Malone and Ashley Maloney and Salvatore Mandra and James M. Manyika and Leigh S. Martin and Orion Martin and Steven Martin and Yossi Matias and Cameron Maxfield and Jarrod R. McClean and Matt McEwen and Seneca Meeks and Anthony Megrant and Xiao Mi and Kevin C. Miao and Amanda Mieszala and Reza Molavi and Sebastian Molina and Shirin Montazeri and Alexis Morvan and Ramis Movassagh and Wojciech Mruczkiewicz and Ofer Naaman and Matthew Neeley and Charles Neill and Ani Nersisyan and Hartmut Neven and Michael Newman and Jiun How Ng and Anthony Nguyen and Murray Nguyen and Chia-Hung Ni and Murphy Yuezhen Niu and Logan Oas and Thomas E. O'Brien and William D. Oliver and Alex Opremcak and Kristoffer Ottosson and Andre Petukhov and Alex Pizzuto and John Platt and Rebecca Potter and Orion Pritchard and Leonid P. Pryadko and Chris Quintana and Ganesh Ramachandran and Chandrasekhar Ramanathan and Matthew J. Reagor and John Redding and David M. Rhodes and Gabrielle Roberts and Eliott Rosenberg and Emma Rosenfeld and Pedram Roushan and Nicholas C. Rubin and Negar Saei and Daniel Sank and Kannan Sankaragomathi and Kevin J. Satzinger and Alexander Schmidhuber and Henry F. Schurkus and Christopher Schuster and Thomas Schuster and Michael J. Shearn and Aaron Shorter and Noah Shutty and Vladimir Shvarts and Volodymyr Sivak and Jindra Skruzny and Spencer Small and Vadim Smelyanskiy and W. Clarke Smith and Rolando D. Somma and Sofia Springer and George Sterling and Doug Strain and Jordan Suchard and Philippe Suchsland and Aaron Szasz and Alex Sztein and Douglas Thor and Eifu Tomita and Alfredo Torres and M. Mert Torunbalci and Abeer Vaishnav and Justin Vargas and Sergey Vdovichev and Guifre Vidal and Benjamin Villalonga and Catherine Vollgraff Heidweiller and Steven Waltman and Shannon X. Wang and Brayden Ware and Kate Weber and Travis Weidel and Tom Westerhout and Theodore White and Kristi Wong and Bryan W. K. Woo and Cheng Xing and Z. Jamie Yao and Ping Yeh and Bicheng Ying and Juhwan Yoo and Noureldin Yosri and Grayson Young and Adam Zalcman and Chongwei Zhang and Yaxing Zhang and Ningfeng Zhu and Nicholas Zobrist},
journal= {arXiv preprint arXiv:2506.10191},
year = {2025}
}
Comments
See following link: https://zenodo.org/records/15640503, which includes: Circuits used in Fig. 3d, Fig. 3e, Fig. 4a, Fig. 4b of the main text. In addition, OTOC (C^(2)) circuits and data with 95, 40 and 31 qubits are also provided. For system sizes <= 40 qubits, we include exact simulation results. For system sizes > 40, we include experimental data