Probing Deconfined Quantum Criticality Point on a Digital Quantum Computer
Abstract
A deconfined quantum critical point (DQCP) is a continuous transition between ordered phases with unrelated broken symmetries, beyond the Landau-Ginzburg-Wilson paradigm. In one dimension, such a transition between a z-polarized ferromagnet (zFM) and a valence-bond solid (VBS) is well established numerically in a frustrated spin-1/2 chain. Here we ask whether a superconducting quantum processor can resolve this transition and its signatures despite finite-size effects and device noise. The ground states are prepared by ancilla-projected quantum imaginary-time evolution (QITE), whose exact target states are compressed by tensor-network optimization into shallow depth quantum circuits. The hardware data distinguish the phases through their order parameters, spin and dimer correlations, structure factors, correlation ratios, and snapshot distributions. The crossing of the order parameters locates the transition, and its finite-size extrapolation lies close to the thermodynamic-limit value obtained from large-scale numerics. A noise model based on the device calibration accounts quantitatively for the reduced amplitudes measured on hardware. Our findings demonstrate that a Landau-forbidden transition between competing orders can be resolved on current quantum processors.
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BibTeX
@misc{giri2026probing,
title = {{Probing Deconfined Quantum Criticality Point on a Digital Quantum Computer}},
author = {Mrinal Kanti Giri and Pinaki Sengupta},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21761},
eprint = {2610.21761},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21761},
}
RIS
TY - UNPB
TI - Probing Deconfined Quantum Criticality Point on a Digital Quantum Computer
AU - Mrinal Kanti Giri
AU - Pinaki Sengupta
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.21761
UR - https://arxiv.org/abs/2610.21761
AB - A deconfined quantum critical point (DQCP) is a continuous transition between ordered phases with unrelated broken symmetries, beyond the Landau-Ginzburg-Wilson paradigm. In one dimension, such a transition between a z-polarized ferromagnet (zFM) and a valence-bond solid (VBS) is well established numerically in a frustrated spin-1/2 chain. Here we ask whether a superconducting quantum processor can resolve this transition and its signatures despite finite-size effects and device noise. The ground states are prepared by ancilla-projected quantum imaginary-time evolution (QITE), whose exact target states are compressed by tensor-network optimization into shallow depth quantum circuits. The hardware data distinguish the phases through their order parameters, spin and dimer correlations, structure factors, correlation ratios, and snapshot distributions. The crossing of the order parameters locates the transition, and its finite-size extrapolation lies close to the thermodynamic-limit value obtained from large-scale numerics. A noise model based on the device calibration accounts quantitatively for the reduced amplitudes measured on hardware. Our findings demonstrate that a Landau-forbidden transition between competing orders can be resolved on current quantum processors.
ER -