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arXiv · 2603.06325

Preparing 100-qubit symmetry-protected topological order on a digital quantum computer

George Pennington·Kevin C. Smith·James R. Garrison·Lachlan P. Lindoy·Jason Crain·Ben Jaderberg
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Abstract

Symmetry-protected topological (SPT) phases extend the Landau paradigm of quantum matter by admitting distinct symmetry-preserving phases that lack any local order parameter. Demonstrating these phases at scale on programmable quantum processors is a key milestone in using quantum hardware to probe emergent many-body phenomena, yet it is impeded by the circuit depth normally required to capture non-trivial entanglement. Here we use a tensor network based approximate quantum compiling (AQC) protocol to construct shallow quantum circuits (18-39 CNOT depth), which prepare 100-site ground states of the spin-1/2 bond-alternating Heisenberg chain in both SPT phases, to 97.9-99.0% fidelity. Upon executing the circuits on IBM quantum hardware, the resulting states exhibit all defining signatures of SPT order including non-local string order for strings of up to length 20, characteristic degeneracies in the entanglement spectrum and clear evidence of symmetry-protected edge modes. The simultaneous observation of these independent diagnostics establishes current quantum computers as versatile platforms for large-scale studies of symmetry-protected quantum matter. More broadly, our results establish a practical foundation for probing non-equilibrium quench dynamics of such systems in regimes that challenge classical computational methods.

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George Pennington, Kevin C. Smith, James R. Garrison, Lachlan P. Lindoy, Jason Crain, Ben Jaderberg. 2026-03-06. Preparing 100-qubit symmetry-protected topological order on a digital quantum computer. https://arxiv.org/abs/2603.06325

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