Phase transitions in parametrized quantum circuits

Fuente: arXiv
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Main Authors: Wang, Xiaoyang, Xu, Han, Broers, Lukas, Shirakawa, Tomonori, Yunoki, Seiji
Format: Preprint
Published: 2026
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_version_ 1866911550949818368
author Wang, Xiaoyang
Xu, Han
Broers, Lukas
Shirakawa, Tomonori
Yunoki, Seiji
author_facet Wang, Xiaoyang
Xu, Han
Broers, Lukas
Shirakawa, Tomonori
Yunoki, Seiji
contents Phase transitions are among the most intriguing phenomena in physical systems, yet their behavior near criticality remain challenging to study using classical algorithms. Parameterized quantum circuits (PQCs) offer a promising approach to investigating such regimes on practical quantum computers. However, in order to use it to probe critical behavior, a PQC itself should be non-trivial and exhibit a phase transition and non-analyticity -- a property that has not yet been clearly identified. In this work, we identify a mechanism for generating non-analyticities intrinsically in PQCs. As a concrete realization, we construct a class of sequential PQCs whose observable expectation value is a non-analytic function of the circuit parameter in the infinite volume limit, showing that the prepared PQC states undergo a phase transition at the non-analytic points. The entanglement and the identified order parameter have distinct behaviors in different phases, revealing a phase diagram of the PQC state. We show that classical simulation of this PQC based on tensor networks and Pauli propagation gets less efficient in the vicinity of the phase transition point, indicating a physically motivated route towards practical quantum advantage using PQCs with phase transitions.
format Preprint
id arxiv_https___arxiv_org_abs_2603_27532
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Phase transitions in parametrized quantum circuits
Wang, Xiaoyang
Xu, Han
Broers, Lukas
Shirakawa, Tomonori
Yunoki, Seiji
Quantum Physics
Phase transitions are among the most intriguing phenomena in physical systems, yet their behavior near criticality remain challenging to study using classical algorithms. Parameterized quantum circuits (PQCs) offer a promising approach to investigating such regimes on practical quantum computers. However, in order to use it to probe critical behavior, a PQC itself should be non-trivial and exhibit a phase transition and non-analyticity -- a property that has not yet been clearly identified. In this work, we identify a mechanism for generating non-analyticities intrinsically in PQCs. As a concrete realization, we construct a class of sequential PQCs whose observable expectation value is a non-analytic function of the circuit parameter in the infinite volume limit, showing that the prepared PQC states undergo a phase transition at the non-analytic points. The entanglement and the identified order parameter have distinct behaviors in different phases, revealing a phase diagram of the PQC state. We show that classical simulation of this PQC based on tensor networks and Pauli propagation gets less efficient in the vicinity of the phase transition point, indicating a physically motivated route towards practical quantum advantage using PQCs with phase transitions.
title Phase transitions in parametrized quantum circuits
topic Quantum Physics
url https://arxiv.org/abs/2603.27532