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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-8434
DTSTART:20230921T203000Z
DURATION:PT1H0M0S
DTSTAMP:20260414T065808Z
LAST-MODIFIED:20230926T150008Z
LOCATION:Discovery Building\, DeLuca Forum
SUMMARY:Entangled quantum cellular automata\, physical complexity\, an
 d Goldilocks rules\, R. G. Herb Condensed Matter Seminar\, Lincoln Car
 r\, Colorado School of Mines
DESCRIPTION:Cellular automata are interacting classical bits that disp
 lay diverse emergent behaviors\, from fractals to random-number genera
 tors to Turing-complete computation. We discover that quantum cellular
  automata (QCA) can exhibit complexity in the sense of the complexity 
 science that describes biology\, sociology\, and economics. QCA exhibi
 t complexity when evolving under 'Goldilocks rules' that we define by 
 balancing activity and stasis. Our Goldilocks rules generate robust dy
 namical features (entangled breathers)\, network structure and dynamic
 s consistent with complexity\, and persistent entropy fluctuations. Pr
 esent-day experimental platforms—Rydberg arrays\, trapped ions\, and
  superconducting qubits—can implement our Goldilocks protocols\, mak
 ing testable the link between complexity science and quantum computati
 on exposed by our QCA. The inability of classical computers to simulat
 e large quantum systems is a hindrance to understanding the physics of
  QCA\, but quantum computers offer an ideal simulation platform. I wil
 l discuss our recent experimental realization of QCA on a digital quan
 tum processor\, simulating a one-dimensional Goldilocks QCA rule on ch
 ains of up to 23 superconducting qubits. Employing low-overhead calibr
 ation and error mitigation techniques\, we calculate population dynami
 cs and complex network measures indicating the formation of small-worl
 d mutual information networks. Unlike random states\, these networks d
 ecohere at fixed circuit depth independent of system size\, the larges
 t of which corresponds to 1\,056 two-qubit gates. This quantum circuit
  depth result presents a strong contrast to the quantum volume concept
  used to characterize many current quantum computers in industry. Such
  computations may open the door to the employment of QCA in applicatio
 ns like the simulation of strongly-correlated matter or beyond-classic
 al computational demonstrations.
URL:https://www.physics.wisc.edu/events/?id=8434
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