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The deterministic preparation of quantum many-body ground states is essential for advanced quantum simulation, yet optimal algorithms often require prohibitive hardware resources. Here, we propose a highly efficient, non-variational…

Quantum Physics · Physics 2026-05-21 Jeongbin Jo

The Variational Quantum Eigensolver (VQE) is a Variational Quantum Algorithm (VQA) to determine the ground state of quantum-mechanical systems. As a VQA, it makes use of a classical computer to optimize parameter values for its quantum…

Quantum Physics · Physics 2025-11-13 Felix Truger , Johanna Barzen , Frank Leymann , Julian Obst

The preparation of quantum Gibbs states is a fundamental challenge in quantum computing, essential for applications ranging from modeling open quantum systems to quantum machine learning. Building on the Meta-Variational Quantum Eigensolver…

Quantum Physics · Physics 2025-10-20 Ruchira V Bhat , Rahul Bhowmick , Avinash Singh , Krishna Kumar Sabapathy

Preparation of quantum thermal states of many-body systems is a key computational challenge for quantum processors, with applications in physics, chemistry, and classical optimization. We provide a simple and efficient algorithm for thermal…

Quantum Physics · Physics 2026-03-18 Jerome Lloyd , Dmitry A. Abanin

Quantum mechanical problems are among the hardest to simulate and, in some cases, remain intractable even for the most powerful computers. Quantum computing has emerged as a new technological platform to address such challenges, with rapid…

Quantum Physics · Physics 2025-09-01 Alexander Miessen

The preparation of $n$-qubit quantum states is a cross-cutting subroutine for many quantum algorithms, and the effort to reduce its circuit complexity is a significant challenge. In the literature, the quantum state preparation algorithm by…

Quantum Physics · Physics 2026-02-09 Giacomo Belli , Michele Amoretti

We provide explicit circuits implementing the Kitaev-Webb algorithm for the preparation of multi-dimensional Gaussian states on quantum computers. While asymptotically efficient due to its polynomial scaling, we find that the circuits…

Quantum Physics · Physics 2021-09-24 Christian W. Bauer , Plato Deliyannis , Marat Freytsis , Benjamin Nachman

Ground-state preparation for a given Hamiltonian is a common quantum-computing task of great importance and has relevant applications in quantum chemistry, computational material modeling, and combinatorial optimization. We consider an…

Quantum Physics · Physics 2022-10-18 Yu-Qin Chen , Shi-Xin Zhang , Chang-Yu Hsieh , Shengyu Zhang

Quantum simulators have the potential to shed light on the study of quantum many-body systems and materials, offering unique insights into various quantum phenomena. While adiabatic evolution has been conventionally employed for state…

Quantum Physics · Physics 2024-04-05 Simon Bernier , Kartiek Agarwal

We study the question of when investing additional quantum resources in preparing a ground state will improve the aggregate runtime associated with estimating its energy. We analyze Lin and Tong's near-optimal state preparation algorithm…

Quantum Physics · Physics 2023-04-26 Shivesh Pathak , Antonio Russo , Stefan Seritan , Andrew Baczewski

Black-box quantum state preparation is a fundamental primitive in quantum algorithms. Starting from Grover, a series of techniques have been devised to reduce the complexity. In this work, we propose to perform black-box state preparation…

We devise a quasilinear quantum algorithm for generating an approximation for the ground state of a quantum field theory (QFT). Our quantum algorithm delivers a super-quadratic speedup over the state-of-the-art quantum algorithm for…

The scalability of solid state quantum computation relies on the ability of connecting the qubits to the macroscopic world. Quantum chains can be used as quantum wires to keep regions of external control at a distance. However even in the…

Quantum Physics · Physics 2007-06-22 D. Burgarth , V. Giovannetti , S. Bose

We present two techniques that can greatly reduce the number of gates required to realize an energy measurement, with application to ground state preparation in quantum simulations. The first technique realizes that to prepare the ground…

Quantum Physics · Physics 2018-08-28 David Poulin , Alexei Kitaev , Damian S. Steiger , Matthew B. Hastings , Matthias Troyer

Renormalization group ideas and effective operators are used to efficiently determine localized unitaries for preparing the ground states of non-interacting scalar field theories on digital quantum devices. With these methods, classically…

Quantum Physics · Physics 2020-12-30 Natalie Klco , Martin J. Savage

State preparation for quantum algorithms is crucial for achieving high accuracy in quantum chemistry and competing with classical algorithms. The localized active space unitary coupled cluster (LAS-UCC) algorithm iteratively loads a…

Quantum Physics · Physics 2023-06-08 Ruhee D'Cunha , Matthew Otten , Matthew R. Hermes , Laura Gagliardi , Stephen K. Gray

Variational quantum algorithms (VQAs) have the potential to demonstrate quantum utility on near-term quantum computers. However, these algorithms often get executed on the highest-fidelity qubits and computers to achieve the best…

Quantum Physics · Physics 2025-10-13 Yuqian Huo , David Quiroga , Anastasios Kyrillidis , Tirthak Patel

Controlled quantum mechanical devices provide a means of simulating more complex quantum systems exponentially faster than classical computers. Such "quantum simulators" rely heavily upon being able to prepare the ground state of…

Quantum Physics · Physics 2012-08-01 Dvir Kafri , Jacob M. Taylor

Variational quantum algorithms (VQAs) have enabled a wide range of applications on near-term quantum devices. However, their scalability is fundamentally limited by barren plateaus, where the probability of encountering large gradients…

Quantum Physics · Physics 2025-07-22 Elias Zapusek , Ivan Rojkov , Florentin Reiter

As standard data loading processes, quantum state preparation and block-encoding are critical and necessary processes for quantum computing applications, including quantum machine learning, Hamiltonian simulation, and many others. Yet,…

Quantum Physics · Physics 2025-12-18 Xiao-Ming Zhang