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In recent years, advanced deep neural networks have required a large number of parameters for training. Therefore, finding a method to reduce the number of parameters has become crucial for achieving efficient training. This work proposes a…

The Quantum Approximate Optimization Algorithm (QAOA) is a leading approach for solving combinatorial optimization problems on near-term quantum processors. However, finding good variational parameters remains a significant challenge due to…

Quantum Physics · Physics 2025-12-05 Yu-Cheng Lin , Yu-Chao Hsu , Samuel Yen-Chi Chen

We consider the Brownian SYK model of $N$ interacting Majorana fermions, with random couplings that are taken to vary independently at each time. We study the out-of-time-ordered correlators (OTOCs) of arbitrary observables and the…

Quantum Physics · Physics 2019-11-14 Christoph Sünderhauf , Lorenzo Piroli , Xiao-Liang Qi , Norbert Schuch , J. Ignacio Cirac

In a quantum system coupled with a non-Markovian environment, quantum information may flow out of or in to the system. Measuring quantum information flow and its sensitivity to perturbations is important for a better understanding of open…

Quantum Physics · Physics 2020-12-01 Mohamad Niknam , Lea F. Santos , David G. Cory

In the recent quantum echoes experiment, Google Quantum AI showed that out-of-time-order correlators (OTOCs) for random-circuit time evolution can be measured using a quantum processor more than 10,000x faster than they can be computed to…

Quantum Physics · Physics 2026-04-20 Pablo Bermejo , Benjamin Villalonga , Brayden Ware , Guifre Vidal , Aaron Szasz

This paper focuses on online kernel learning over a decentralized network. Each agent in the network receives continuous streaming data locally and works collaboratively to learn a nonlinear prediction function that is globally optimal in…

Machine Learning · Computer Science 2022-08-05 Ping Xu , Yue Wang , Xiang Chen , Zhi Tian

OTOC has been used to characterize the information scrambling in quantum systems. Recent studies showed that local conserved quantities play a crucial role in governing the relaxation dynamics of OTOC in non-integrable systems. In…

Statistical Mechanics · Physics 2023-01-11 Vinitha Balachandran , Dario Poletti

Quantum kernel methods are a promising branch of quantum machine learning, yet their effectiveness on diverse, high-dimensional, real-world data remains unverified. Current research has largely been limited to low-dimensional or synthetic…

Machine Learning · Computer Science 2026-02-19 Jiang Yuhan , Matthew Otten

Two topics, evolving rapidly in separate fields, were combined recently: The out-of-time-ordered correlator (OTOC) signals quantum-information scrambling in many-body systems. The Kirkwood-Dirac (KD) quasiprobability represents operators in…

Quantum Physics · Physics 2018-04-12 Nicole Yunger Halpern , Brian Swingle , Justin Dressel

Using the parametric representation of a chaotic many-body quantum system derived earlier, we calculate explicitly the large-time dependence and asymptotic value of the out-of-time correlator (OTOC) of that system. The dependence on time…

Mathematical Physics · Physics 2025-05-12 Hans A. Weidenmüller

Out-of-Time-Ordered Commutators (OTOCs), representing a key diagnostic for scrambling as a facet of short-time quantum chaos, have attracted wide-ranging interest, from many-body physics to quantum gravity. By means of a suitable form of…

Chaotic Dynamics · Physics 2025-12-24 Fabian Haneder , Gerrit Caspari , Juan Diego Urbina , Klaus Richter

We investigate the onset of chaos in a periodically kicked Dicke model (KDM), using the out-of-time-order correlator (OTOC) as a diagnostic tool, in both the oscillator and the spin subspaces. In the large spin limit, the classical…

Statistical Mechanics · Physics 2021-04-26 Sudip Sinha , Sayak Ray , Subhasis Sinha

In recent years, quantum kernel methods have shown promising applications on near-term quantum devices. However, selecting an appropriate encoding circuit for a given dataset requires costly evaluation of multiple candidates, formulated as…

Quantum Physics · Physics 2026-04-22 Dao Duy Tung , Nguyen Quoc Chuong , Vu Tuan Hai , Le Bin Ho , Lan Nguyen Tran

We investigate the classical-quantum correspondence in the inverted harmonic oscillator (IHO) system. It is shown that the out-of-time-order correlators (OTOCs) which the initial states are located at any position in the IHO system possess…

Quantum Physics · Physics 2024-12-09 Shangyun Wang , Songbai Chen , Jiliang Jing

Determining the Hamiltonian of a quantum system is essential for understanding its dynamics and validating its behavior. Hamiltonian learning provides a data-driven approach to reconstruct the generator of the dynamics from measurements on…

This paper addresses the challenges of training large neural network models under federated learning settings: high on-device memory usage and communication cost. The proposed Online Model Compression (OMC) provides a framework that stores…

Machine Learning · Computer Science 2022-05-10 Tien-Ju Yang , Yonghui Xiao , Giovanni Motta , Françoise Beaufays , Rajiv Mathews , Mingqing Chen

The Out-of-Time-Order Correlator (OTOC) is a standard algebraic diagnostic of quantum information scrambling, but it offers limited direct geometric intuition. In this note, we propose a Bohmian, trajectory-based framework for constructing…

Quantum Physics · Physics 2026-03-24 Stephen Wiggins

Out-of-time ordered (OTO) correlation functions describe scrambling of information in correlated quantum matter. They are of particular interest in incoherent quantum systems lacking well defined quasi-particles. Thus far, it is largely…

Quantum Gases · Physics 2017-06-06 A. Bohrdt , C. B. Mendl , M. Endres , M. Knap

Hamiltonian dynamics describe a wide range of physical systems. As such, data-driven simulations of Hamiltonian systems are important for many scientific and engineering problems. In this work, we propose kernel-based methods for…

Numerical Analysis · Mathematics 2025-09-23 Yasamin Jalalian , Mostafa Samir , Boumediene Hamzi , Peyman Tavallali , Houman Owhadi

The out-of-time-ordered correlator (OTOC) diagnoses quantum chaos and the scrambling of quantum information via the spread of entanglement. The OTOC encodes forward and reverse evolutions and has deep connections with the flow of time. So…

Quantum Physics · Physics 2017-01-20 Nicole Yunger Halpern