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Related papers: Generalized quantum circuit differentiation rules

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Symmetries are crucial for tailoring parametrized quantum circuits to applications, due to their capability to capture the essence of physical systems. In this work, we shift the focus away from incorporating symmetries in the circuit…

Quantum Physics · Physics 2023-12-13 David Wierichs , Richard D. P. East , Martín Larocca , M. Cerezo , Nathan Killoran

Many optimization methods for training variational quantum algorithms are based on estimating gradients of the cost function. Due to the statistical nature of quantum measurements, this estimation requires many circuit evaluations, which is…

Quantum Physics · Physics 2022-10-14 Lennart Bittel , Jens Watty , Martin Kliesch

Variational quantum circuits characterise the state of a quantum system through the use of parameters that are optimised using classical optimisation procedures that typically rely on gradient information. The circuit-execution complexity…

Quantum Physics · Physics 2023-07-28 Sayantan Pramanik , Chaitanya Murti , M Girish Chandra

The phase shift rules enable the estimation of the derivative of a quantum state with respect to phase parameters, providing valuable insights into the behavior and dynamics of quantum systems. This capability is essential in quantum…

Quantum Physics · Physics 2023-09-15 L. A. Markovich , S. Malikis , S. Polla , J. T. Brugués

Quantum mechanics fundamentally forbids deterministic discrimination of quantum states and processes. However, the ability to optimally distinguish various classes of quantum data is an important primitive in quantum information science. In…

Quantum Physics · Physics 2021-03-10 Hongxiang Chen , Leonard Wossnig , Simone Severini , Hartmut Neven , Masoud Mohseni

Finding gradients is a crucial step in training machine learning models. For quantum neural networks, computing gradients using the parameter-shift rule requires calculating the cost function twice for each adjustable parameter in the…

Quantum Physics · Physics 2025-01-31 Guang Ping He

Many promising quantum algorithms in economics, medical science, and material science rely on circuits that are parameterized by a large number of angles. To ensure that these algorithms are efficient, these parameterized circuits must be…

Quantum Physics · Physics 2025-07-09 Neil J. Ross , Scott Wesley

Quantum computers can efficiently sample from probability distributions that are believed to be classically intractable, providing a foundation for quantum generative modeling. However, practical training of such models remains challenging,…

Quantum Physics · Physics 2025-11-18 Maria Demidik , Cenk Tüysüz , Michele Grossi , Karl Jansen

In this work we present a novel strategy to evaluate multi-variable integrals with quantum circuits. The procedure first encodes the integration variables into a parametric circuit. The obtained circuit is then derived with respect to the…

Quantum Physics · Physics 2024-07-17 Juan M. Cruz-Martinez , Matteo Robbiati , Stefano Carrazza

Unitary and non-unitary diagonal operators are fundamental building blocks in quantum algorithms with applications in the resolution of partial differential equations, Hamiltonian simulations, the loading of classical data on quantum…

Quantum Physics · Physics 2025-01-22 Julien Zylberman , Ugo Nzongani , Andrea Simonetto , Fabrice Debbasch

We discuss a Quantum Non-Demolition Measurement (QNDM) protocol to estimate the derivatives of a cost function with a quantum computer. %This is a key step for the implementation of variational quantum circuits. The cost function, which is…

Quantum Physics · Physics 2023-06-07 Paolo Solinas , Simone Caletti , Giovanni Minuto

Quantum generative modeling is a growing area of interest for industry-relevant applications. With the field still in its infancy, there are many competing techniques. This work is an attempt to systematically compare a broad range of these…

We present a quantum variational algorithm based on a novel circuit that generates all permutations that can be spanned by one- and two-qubits permutation gates. The construction of the circuits follows from group-theoretical results, most…

Quantum Physics · Physics 2026-02-11 Dylan Laplace Mermoud , Andrea Simonetto , Sourour Elloumi

Currently available quantum hardware allows for small scale implementations of quantum machine learning algorithms. Such experiments aid the search for applications of quantum computers by benchmarking the near-term feasibility of candidate…

Quantum Physics · Physics 2021-09-08 Michael R. Geller , Zoë Holmes , Patrick J. Coles , Andrew Sornborger

Unlike most classical algorithms that take an input and give the solution directly as an output, quantum algorithms produce a quantum circuit that works as an indirect solution to computationally hard problems. In the full quantum computing…

Quantum Physics · Physics 2025-05-22 Yikai Mao , Shaswot Shresthamali , Masaaki Kondo

We define syntax and semantics of quantum circuits, allowing measurement gates and classical channels. We define circuit-based quantum algorithms and prove that, semantically, any such algorithm is equivalent to a single measurement that…

Quantum Physics · Physics 2021-07-20 Yuri Gurevich , Andreas Blass

We present an explicit construction of a relativistic quantum computing architecture using a variational quantum circuit approach that is shown to allow for universal quantum computing. The variational quantum circuit consists of tunable…

Quantum Physics · Physics 2025-05-19 Philip A. LeMaitre , T. Rick Perche , Marius Krumm , Hans J. Briegel

Quantum state tomography is a key process in most quantum experiments. In this work, we employ quantum machine learning for state tomography. Given an unknown quantum state, it can be learned by maximizing the fidelity between the output of…

We present a unitary-based gradient formulation for variational quantum algorithms (VQAs) that applies to general differentiable cost function defined by a parameterized quantum circuit composed of Pauli-generated rotations. The gradient is…

Quantum Physics · Physics 2026-04-02 Jesus Urbaneja , Le Bin Ho

The role of differential equations (DEs) in science and engineering is of paramount importance, as they provide the mathematical framework for a multitude of natural phenomena. Since quantum computers promise significant advantages over…

Quantum Physics · Physics 2025-04-11 Niclas Schillo , Andreas Sturm