Observation of Time-Crystalline Eigenstate Order on a Quantum Processor
Creators: name: Mi, Xiao
name: Ippoliti, Matteo
name: Quintana, Chris
name: Greene, Ami
name: Chen, Zijun
name: Gross, Jonathan
name: Arute, Frank
name: Arya, Kunal
name: Atalaya, Juan
name: Babbush, Ryan
name: Bardin, Joseph C.
name: Basso, Joao
name: Bengtsson, Andreas
name: Bilmes, Alexander
name: Bourassa, Alexandre
name: Brill, Leon
name: Broughton, Michael
name: Buckley, Bob B.
name: Buell, David A.
name: Burkett, Brian
name: Bushnell, Nicholas
name: Chiaro, Benjamin
name: Collins, Roberto
name: Courtney, William
name: Debroy, Dripto
name: Demura, Sean
name: Derk, Alan R.
name: Dunsworth, Andrew
name: Eppens, Daniel
name: Erickson, Catherine
name: Farhi, Edward
name: Fowler, Austin G.
name: Foxen, Brooks
name: Gidney, Craig
name: Giustina, Marissa
name: Harrigan, Matthew P.
name: Harrington, Sean D.
name: Hilton, Jeremy
name: Ho, Alan
name: Hong, Sabrina
name: Huang, Trent
name: Huff, Ashley
name: Huggins, William J.
name: Ioffe, L. B.
name: Isakov, Sergei V.
name: Iveland, Justin
name: Jeffrey, Evan
name: Jiang, Zhang
name: Jones, Cody
name: Kafri, Dvir
name: Khattar, Tanuj
name: Kim, Seon
name: Kitaev, Alexei
name: Klimov, Paul V.
name: Korotkov, Alexander N.
name: Kostritsa, Fedor
name: Landhuis, David
name: Laptev, Pavel
name: Lee, Joonho
name: Lee, Kenny
name: Locharla, Aditya
name: Lucero, Erik
name: Martin, Orion
name: McClean, Jarrod R.
name: McCourt, Trevor
name: McEwen, Matt
name: Miao, Kevin C.
name: Mohseni, Masoud
name: Montazeri, Shirin
name: Mruczkiewicz, Wojciech
name: Naaman, Ofer
name: Neeley, Matthew
name: Neill, Charles
name: Newman, Michael
name: Niu, Murphy Yuezhen
name: Brien, Thomas E. O\'
name: Opremcak, Alex
name: Ostby, Eric
name: Pato, Balint
name: Petukhov, Andre
name: Rubin, Nicholas C.
name: Sank, Daniel
name: Satzinger, Kevin J.
name: Shvarts, Vladimir
name: Su, Yuan
name: Strain, Doug
name: Szalay, Marco
name: Trevithick, Matthew D.
name: Villalonga, Benjamin
name: White, Theodore
name: Yao, Z. Jamie
name: Yeh, Ping
name: Yoo, Juhwan
name: Zalcman, Adam
name: Neven, Hartmut
name: Boixo, Sergio
name: Smelyanskiy, Vadim
name: Megrant, Anthony
name: Kelly, Julian
name: Chen, Yu
name: Sondhi, S. L.
name: Moessner, Roderich
name: Kechedzhi, Kostyantyn
name: Khemani, Vedika
name: Roushan, Pedram
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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.