Revisiting Nishimori multicriticality through the lens of information measures

Fuente: arXiv
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Auteurs principaux: Wan, Zhou-Quan, Dai, Xu-Dong, Zhu, Guo-Yi
Format: Preprint
Publié: 2025
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author Wan, Zhou-Quan
Dai, Xu-Dong
Zhu, Guo-Yi
author_facet Wan, Zhou-Quan
Dai, Xu-Dong
Zhu, Guo-Yi
contents The quantum error correction threshold is closely related to the Nishimori physics of random statistical models. We extend quantum information measures such as coherent information beyond the Nishimori line and establish them as sharp indicators of phase transitions over the full $p$-$T$ plane. These generalized measures admit a natural operational interpretation as diagnostics of inference mismatch for decoders operating at an effective temperature. We derive exact inequalities for several generalized measures, demonstrating that each attains its extremum along the Nishimori line. As a direct application, we study these measures in the 2d $\pm J$ random-bond Ising model-corresponding to a surface code under bit-flip noise-and revisit the Nishimori multicritical point. Among all indicators, coherent information exhibits the weakest finite-size effects, enabling a high-precision estimate $p_c=0.1092212(4)$ and the associated critical exponents.
format Preprint
id arxiv_https___arxiv_org_abs_2511_02907
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Revisiting Nishimori multicriticality through the lens of information measures
Wan, Zhou-Quan
Dai, Xu-Dong
Zhu, Guo-Yi
Statistical Mechanics
Disordered Systems and Neural Networks
Strongly Correlated Electrons
Quantum Physics
The quantum error correction threshold is closely related to the Nishimori physics of random statistical models. We extend quantum information measures such as coherent information beyond the Nishimori line and establish them as sharp indicators of phase transitions over the full $p$-$T$ plane. These generalized measures admit a natural operational interpretation as diagnostics of inference mismatch for decoders operating at an effective temperature. We derive exact inequalities for several generalized measures, demonstrating that each attains its extremum along the Nishimori line. As a direct application, we study these measures in the 2d $\pm J$ random-bond Ising model-corresponding to a surface code under bit-flip noise-and revisit the Nishimori multicritical point. Among all indicators, coherent information exhibits the weakest finite-size effects, enabling a high-precision estimate $p_c=0.1092212(4)$ and the associated critical exponents.
title Revisiting Nishimori multicriticality through the lens of information measures
topic Statistical Mechanics
Disordered Systems and Neural Networks
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2511.02907