Logan E. Hillberry,  The University of Texas at Austin

"Entangled quantum cellular automata, physical complexity, and Goldilocks rules"

Abstract: Cellular automata are interacting classical bits that display diverse emergent behaviors, from fractals to random-number generators to Turing-complete computation. In this talk, I will discuss quantum cellular automata (QCA) and show that they can exhibit complexity in the sense of the complexity science that describes biology, sociology, and economics. QCA exhibit complexity when evolving under “Goldilocks rules” that I will define by balancing activity and stasis. The Goldilocks rules generate robust dynamical features (entangled breathers), network structure and dynamics consistent with complexity, and persistent entropy fluctuations. Present-day experimental platforms — Rydberg arrays, trapped ions, and superconducting qubits — can implement our Goldilocks protocols, making testable the link between complexity science and quantum computation exposed by Goldilocks QCA.

Reference:
Logan E. Hillberry, Matthew T. Jones, David L. Vargas, Patrick Rall, Nicole Yunger Halpern, Ning Bao, Simone Notarnicola, Simone Montangero, and Lincoln D. Carr, Entangled quantum cellular automata, physical complexity, and Goldilocks rules (2021), arXiv:2005.01763[quant-ph]. (to appear in QST).