@article{10272/22553,
year = {2023},
url = {https://hdl.handle.net/10272/22553},
abstract = {Transmon qubits are the predominant element in circuit-based quantum information processing, such as existing quantum computers, due to their controllability and ease of engineering implementation. But more than qubits, transmons are multilevel nonlinear oscillators that can be used to investigate fundamental physics questions. Here, they are explored as simulators of excited state quantum phase transitions (ESQPTs), which are generalizations of quantum phase transitions to excited states. We show that the spectral kissing (coalescence of pairs of energy levels) experimentally observed in the effective Hamiltonian of a driven SNAIL-transmon is an ESQPT precursor. We explore the dynamical consequences of the ESQPT, which include the exponential growth of out-of-time-ordered correlators, followed by periodic revivals, and the slow evolution of the survival probability due to localization. These signatures of ESQPT are within reach for current superconducting circuits platforms and are of interest to experiments with cold atoms and ion traps.},
organization = {This research was supported by the NSF CCI grant (Award Number 2124511). T.L.M.L.
was funded by the NSF grant No. DMR-1936006. F.P.B. was funded by the I+D+i
project PID2019-104002GB-C21 (MCIN/AEI/10.13039/501100-011033) and by the
Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía and
European Regional Development Fund (ERDF), ref. UHU-1262561. Computing
resources supporting this work were partly provided by the CEAFMC and Universidad
de Huelva High Performance Computer (HPC@UHU) located in the Campus
Universitario el Carmen and funded by FEDER/MINECO project UNHU-15CE-2848.
L.F.S. had support from the MPS Simons Foundation Award ID: 678586. J.C.C. and
L.F.S. thank Jorge Hirsch and his group for various discussions on OTOCs and ESQPTs.},
publisher = {Nature Research},
title = {Spectral kissing and its dynamical consequences in the squeeze-driven Kerr oscillator},
doi = {10.1038/s41534-023-00745-1},
author = {Chávez Carlos, Jorge and Lezama, Talía L. M. and Cortiñas, Rodrigo G. and Venkatraman, Jayameenakshi and Devoret, Michel H. and Batista, Victor S. and Pérez Bernal, Francisco and Santos, Lea F.},
}