Observation of Time-Crystalline Eigenstate Order on a Quantum Processor
Abstract
Quantum many-body systems display rich phase structure in their low-temperature equilibrium states. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC). Concretely, dynamical phases can be defined in periodically driven many-body localized systems via the concept of eigenstate order. In eigenstate-ordered phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, wherein few select states can mask typical behavior. Here we implement a continuous family of tunable CPHASE gates on an array of superconducting qubits to experimentally observe an eigenstate-ordered DTC. We demonstrate the characteristic spatiotemporal response of a DTC for generic initial states. Our work employs a time-reversal protocol that discriminates external decoherence from intrinsic thermalization, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. In addition, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to study non-equilibrium phases of matter on current quantum processors.
Cite
@article{arxiv.2107.13571,
title = {Observation of Time-Crystalline Eigenstate Order on a Quantum Processor},
author = {Xiao Mi and Matteo Ippoliti and Chris Quintana and Ami Greene and Zijun Chen and Jonathan Gross and Frank Arute and Kunal Arya and Juan Atalaya and Ryan Babbush and Joseph C. Bardin and Joao Basso and Andreas Bengtsson and Alexander Bilmes and Alexandre Bourassa and Leon Brill and Michael Broughton and Bob B. Buckley and David A. Buell and Brian Burkett and Nicholas Bushnell and Benjamin Chiaro and Roberto Collins and William Courtney and Dripto Debroy and Sean Demura and Alan R. Derk and Andrew Dunsworth and Daniel Eppens and Catherine Erickson and Edward Farhi and Austin G. Fowler and Brooks Foxen and Craig Gidney and Marissa Giustina and Matthew P. Harrigan and Sean D. Harrington and Jeremy Hilton and Alan Ho and Sabrina Hong and Trent Huang and Ashley Huff and William J. Huggins and L. B. Ioffe and Sergei V. Isakov and Justin Iveland and Evan Jeffrey and Zhang Jiang and Cody Jones and Dvir Kafri and Tanuj Khattar and Seon Kim and Alexei Kitaev and Paul V. Klimov and Alexander N. Korotkov and Fedor Kostritsa and David Landhuis and Pavel Laptev and Joonho Lee and Kenny Lee and Aditya Locharla and Erik Lucero and Orion Martin and Jarrod R. McClean and Trevor McCourt and Matt McEwen and Kevin C. Miao and Masoud Mohseni and Shirin Montazeri and Wojciech Mruczkiewicz and Ofer Naaman and Matthew Neeley and Charles Neill and Michael Newman and Murphy Yuezhen Niu and Thomas E. O\' Brien and Alex Opremcak and Eric Ostby and Balint Pato and Andre Petukhov and Nicholas C. Rubin and Daniel Sank and Kevin J. Satzinger and Vladimir Shvarts and Yuan Su and Doug Strain and Marco Szalay and Matthew D. Trevithick and Benjamin Villalonga and Theodore White and Z. Jamie Yao and Ping Yeh and Juhwan Yoo and Adam Zalcman and Hartmut Neven and Sergio Boixo and Vadim Smelyanskiy and Anthony Megrant and Julian Kelly and Yu Chen and S. L. Sondhi and Roderich Moessner and Kostyantyn Kechedzhi and Vedika Khemani and Pedram Roushan},
journal= {arXiv preprint arXiv:2107.13571},
year = {2022}
}