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We study the effects of an arbitrary external perturbation in the statistical properties of the S-matrix of quantum chaotic scattering systems in the limit of isolated resonances. We derive, using supersymmetry, an exact non-perturbative…

Condensed Matter · Physics 2009-10-22 A. M. S. Macedo

Accurate characterization of quantum systems is essential for the development of quantum technologies, particularly in the noisy intermediate-scale quantum (NISQ) era. While traditional methods for Hamiltonian learning and noise…

Quantum Physics · Physics 2025-07-18 Gubio G. de Lima , Iann Cunha , Leonardo Kleber Castelano

In the current era, known as Noisy Intermediate-Scale Quantum (NISQ), encoding large amounts of data in the quantum devices is challenging and the impact of noise significantly affects the quality of the obtained results. A viable approach…

Emerging Technologies · Computer Science 2024-03-26 Emiliano Tolotti , Enrico Zardini , Enrico Blanzieri , Davide Pastorello

The variational quantum eigensolver is a promising way to solve the Schr\"odinger equation on a noisy intermediate-scale quantum (NISQ) computer, while its success relies on a well-designed wavefunction ansatz. Compared to physically…

Quantum Physics · Physics 2023-01-20 Xiongzhi Zeng , Yi Fan , Jie Liu , Zhenyu Li , Jinlong Yang

Quantum sensing is an important application of emerging quantum technologies. We explore whether a hybrid system of quantum sensors and quantum circuits can surpass the classical limit of sensing. In particular, we use optimization…

The design of efficient quantum circuits is an important issue in quantum computing. It is in general a formidable task to find a highly optimized quantum circuit for a given unitary matrix. We propose a quantum circuit design method that…

Quantum Physics · Physics 2023-11-27 Andreas Klappenecker , Martin Roetteler

Finding ground states and low-lying excitations of a given Hamiltonian is one of the most important problems in many fields of physics. As a novel approach, quantum computing on Noisy Intermediate-Scale Quantum (NISQ) devices offers the…

We argue that the quantum-theoretical structures studied in several recent lines of research cannot be adequately described within the standard framework of quantum circuits. This is in particular the case whenever the combination of…

Quantum Physics · Physics 2021-07-14 Augustin Vanrietvelde , Hlér Kristjánsson , Jonathan Barrett

During the noisy intermediate-scale quantum (NISQ) era, it is important to optimize the quantum circuits in circuit depth and gate count, especially entanglement gates, including the CNOT gate. Among all the unitary operators, diagonal…

Quantum Physics · Physics 2024-04-15 Xinchi Huang , Taichi Kosugi , Hirofumi Nishi , Yu-ichiro Matsushita

Quantum channels describe the most general dynamics of open quantum systems. A quantum channel, as a linear map on vectorized quantum states, can be represented by a single matrix, whose spectrum is called the channel spectrum. Here we…

Quantum Physics · Physics 2026-01-28 Yuan-De Jin , Wen-Long Ma

Quantum computing is a disruptive technology that is expected to offer significant advantages in many critical fields (e.g. drug discovery and cryptography). The security of information processed by such machines is therefore paramount.…

Quantum Physics · Physics 2026-03-17 Paolo Bernardi , Antonio Brogi , Gian-Luigi Ferrari , Giuseppe Bisicchia

The search for useful applications of noisy intermediate-scale quantum (NISQ) devices in quantum simulation has been hindered by their intrinsic noise and the high costs associated with achieving high accuracy. A promising approach to…

Quantum Physics · Physics 2025-07-01 Emiel Koridon , Felix Frohnert , Eric Prehn , Evert van Nieuwenburg , Jordi Tura , Stefano Polla

With an ever-expanding ecosystem of noisy and intermediate-scale quantum devices, exploring their possible applications is a rapidly growing field of quantum information science. In this work, we demonstrate that variational quantum…

Quantum Physics · Physics 2021-07-16 Johannes Jakob Meyer , Johannes Borregaard , Jens Eisert

We explore quantum chaos diagnostics of variational circuit states at random parameters and study their correlation with the circuit expressibility and the optimization of control parameters. By measuring the operator spreading coefficient…

Quantum Physics · Physics 2023-03-01 Joonho Kim , Yaron Oz , Dario Rosa

Can near-term gate model based quantum processors offer quantum advantage for practical applications in the pre-fault tolerance noise regime? A class of algorithms which have shown some promise in this regard are the so-called…

Quantum Physics · Physics 2019-08-13 Guillaume Verdon , Michael Broughton , Jacob Biamonte

The steady progress of quantum hardware is motivating the search for novel quantum algorithm optimization strategies for near-term, real-world applications. In this study, we propose a novel feature map optimization strategy for Quantum…

Quantum Physics · Physics 2025-03-31 Roberto Moretti , Andrea Giachero , Voica Radescu , Michele Grossi

Random quantum circuit is a minimally structured model to study the entanglement dynamics of many-body quantum systems. In this paper, we considered a one-dimensional quantum circuit with noisy Haar-random unitary gates using density matrix…

Quantum Physics · Physics 2022-05-16 Qi Zhang , Guang-Ming Zhang

The development of Noisy Intermediate Scale Quantum Computers (NISQC) provides for the Quantum Information community new tools to perform quantum experiences from an individual laptop. It facilitates interdisciplinary research in the sense…

Quantum Physics · Physics 2021-01-12 Frédéric Holweck

We present an architecture to investigate wave-particle duality in $N$-path interferometers on a universal quantum computer involving as low as $2\log N$ qubits and develop a measurement scheme which allows the efficient extraction of…

Quantum Physics · Physics 2020-09-10 Mirko Amico , Christoph Dittel

Random feature maps are ubiquitous in modern statistical machine learning, where they generalize random projections by means of powerful, yet often difficult to analyze nonlinear operators. In this paper, we leverage the "concentration"…

Machine Learning · Statistics 2021-03-18 Zhenyu Liao , Romain Couillet