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Related papers: Phase transitions in parametrized quantum circuits

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Learning many-body quantum states and quantum phase transitions remains a major challenge in quantum many-body physics. Classical machine learning methods offer certain advantages in addressing these difficulties. In this work, we propose a…

Quantum Physics · Physics 2026-02-03 Xin Li , Zhang-Qi Yin

The characterization of collective behavior and nonequilibrium phase transitions in quantum systems is typically rooted in the analysis of suitable system observables, so-called order parameters. These observables might not be known a…

Quantum Physics · Physics 2026-02-20 Erik Fitzner , Francesco Carnazza , Federico Carollo , Igor Lesanovsky

We uncover a dynamical entanglement transition in a monitored quantum system that is heralded by a local order parameter. Classically, chaotic systems can be stochastically controlled onto unstable periodic orbits and exhibit controlled and…

Disordered Systems and Neural Networks · Physics 2022-08-10 Thomas Iadecola , Sriram Ganeshan , J. H. Pixley , Justin H. Wilson

Whether parameterized quantum circuits (PQCs) can be systematically constructed to be both trainable and expressive remains an open question. Highly expressive PQCs often exhibit barren plateaus, while several trainable alternatives admit…

Quantum Physics · Physics 2026-03-17 Peter Röseler , Dennis Willsch , Kristel Michielsen

Variational quantum algorithms (VQAs) have emerged as the leading strategy to obtain quantum advantage on the current noisy intermediate-scale devices. However, their entanglement-trainability correlation, as the major reason for the barren…

Quantum Physics · Physics 2025-05-07 Shikun Zhang , Yang Zhou , Zheng Qin , Rui Li , Chunxiao Du , Zhisong Xiao , Yongyou Zhang

Quantum computing has made significant progress in recent years, attracting immense interest not only in research laboratories but also in various industries. However, the application of quantum computing to solve real-world problems is…

Quantum Physics · Physics 2025-05-26 Darya Martyniuk , Johannes Jung , Adrian Paschke

One-way measurement based quantum computations (1WQC) may describe unitary transformations, via a composition of CPTP maps which are not all unitary themselves. This motivates the following decision problems: Is it possible to determine…

Quantum Physics · Physics 2009-10-22 Niel de Beaudrap

The current generation of quantum computing technologies call for quantum algorithms that require a limited number of qubits and quantum gates, and which are robust against errors. A suitable design approach are variational circuits where…

Quantum Physics · Physics 2020-04-10 Maria Schuld , Alex Bocharov , Krysta Svore , Nathan Wiebe

Physical processes in the quantum regime possess non-classical properties of quantum mechanics. However, methods for quantitatively identifying such processes are still lacking. Accordingly, in this study, we develop a framework for…

Quantum Physics · Physics 2020-01-01 Chung-Cheng Kuo , Shih-Hsuan Chen , Wei-Ting Lee , Hung-Ming Chen , He Lu , Che-Ming Li

The contact process is a paradigmatic classical stochastic system displaying critical behavior even in one dimension. It features a non-equilibrium phase transition into an absorbing state that has been widely investigated and shown to…

Statistical Mechanics · Physics 2019-09-11 Federico Carollo , Edward Gillman , Hendrik Weimer , Igor Lesanovsky

Expressibility is a crucial factor of a Parameterized Quantum Circuit (PQC). In the context of Variational Quantum Algorithms (VQA) based Quantum Machine Learning (QML), a QML model composed of highly expressible PQC and sufficient number…

Quantum Physics · Physics 2024-08-12 Yu Liu , Kentaro Baba , Kazuya Kaneko , Naoyuki Takeda , Junpei Koyama , Koichi Kimura

Parameterized quantum circuits (PQCs) have emerged as a foundational element in the development and applications of quantum algorithms. However, when initialized with random parameter values, PQCs often exhibit barren plateaus (BP). These…

Quantum Physics · Physics 2025-07-02 Muhammad Kashif , Muhammad Rashid , Saif Al-Kuwari , Muhammad Shafique

In this work, our prime objective is to study the phenomena of quantum chaos and complexity in the machine learning dynamics of Quantum Neural Network (QNN). A Parameterized Quantum Circuits (PQCs) in the hybrid quantum-classical framework…

High Energy Physics - Theory · Physics 2021-04-16 Sayantan Choudhury , Ankan Dutta , Debisree Ray

Mapping out phase diagrams of quantum systems using classical simulations can be challenging or intractable due to the computational resources required to simulate even small quantum systems far away from the thermodynamic limit. We…

Quantum Physics · Physics 2024-06-05 Jan Lukas Bosse , Raul Santos , Ashley Montanaro

Quantum computing can provide speedups in solving many problems as the evolution of a quantum system is described by a unitary operator in an exponentially large Hilbert space. Such unitary operators change the phase of their eigenstates…

Quantum Physics · Physics 2024-01-23 Youle Wang , Lei Zhang , Zhan Yu , Xin Wang

Diagrammatic representations of quantum algorithms and circuits offer novel approaches to their design and analysis. In this work, we describe extensions of the ZX-calculus especially suitable for parameterized quantum circuits, in…

Quantum Physics · Physics 2023-11-16 Tobias Stollenwerk , Stuart Hadfield

We overview the concept of dynamical phase transitions in isolated quantum systems quenched out of equilibrium. We focus on non-equilibrium transitions characterized by an order parameter, which features qualitatively distinct temporal…

Statistical Mechanics · Physics 2022-10-25 Jamir Marino , Martin Eckstein , Matthew S. Foster , Ana Maria Rey

Hybrid quantum-classical systems make it possible to utilize existing quantum computers to their fullest extent. Within this framework, parameterized quantum circuits can be regarded as machine learning models with remarkable expressive…

Quantum Physics · Physics 2019-11-15 Marcello Benedetti , Erika Lloyd , Stefan Sack , Mattia Fiorentini

Recent developments in quantum computing suggest that it could be possible to make conditional changes to the state of a quantum mechanical system without resorting to classical observation. It is accomplished through collective response of…

Quantum Physics · Physics 2007-05-23 Sarnath Ramnath , Kevin Haglin

We develop classical simulation algorithms for adaptive quantum circuits that produce states with low levels of ``magic'' (i.e., non-stabilizerness). These algorithms are particularly well-suited to circuits with high rates of Pauli…

Quantum Physics · Physics 2026-05-22 Kemal Aziz , Haining Pan , Michael J. Gullans , J. H. Pixley