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Analog quantum simulation is emerging as a powerful tool for uncovering classically unreachable physics such as many-body real-time dynamics. A complete quantification of uncertainties is necessary in order to make precise predictions using…

Quantum Physics · Physics 2024-05-16 Nikita A. Zemlevskiy , Henry F. Froland , Stephan Caspar

We provide a quantum algorithm for simulating the dynamics of sparse Hamiltonians with complexity sublogarithmic in the inverse error, an exponential improvement over previous methods. Specifically, we show that a $d$-sparse Hamiltonian $H$…

Quantum Physics · Physics 2014-10-09 Dominic W. Berry , Andrew M. Childs , Richard Cleve , Robin Kothari , Rolando D. Somma

Product formulae are a popular class of digital quantum simulation algorithms due to their conceptual simplicity, low overhead, and performance which often exceeds theoretical expectations. Recently, Richardson extrapolation and polynomial…

Quantum Physics · Physics 2024-10-10 James D. Watson , Jacob Watkins

Simulation of quantum systems is expected to be one of the most important applications of quantum computing, with much of the theoretical work so far having focused on fermionic and spin-$\frac{1}{2}$ systems. Here, we instead consider…

In this proof-of-concept paper we show that tensor product approach is efficient for control of large quantum systems, such as Heisenberg spin wires, which are essential for emerging quantum computing technologies. We compute optimal…

Numerical Analysis · Mathematics 2019-07-30 Diego Quiñones Valles , Sergey Dolgov , Dmitry Savostyanov

Quantum algorithms for simulation of Hamiltonian evolution are often based on product formulae. The fractal methods give a systematic way to find arbitrarily high-order product formulae, but result in a large number of exponentials. On the…

The large dimensionality of environments is the limiting factor in applying optimal control to open quantum systems beyond Markovian approximations. Multiple methods exist to simulate non-Markovian open systems which effectively reduce the…

Quantum Physics · Physics 2024-10-08 Carlos Ortega-Taberner , Eoin O'Neill , Eoin Butler , Gerald E. Fux , P. R. Eastham

Simulating the time evolution of quantum field theories given some Hamiltonian $H$ requires developing algorithms for implementing the unitary operator e^{-iHt}. A variety of techniques exist that accomplish this task, with the most common…

Classical simulators play a major role in the development and benchmark of quantum algorithms and practically any software framework for quantum computation provides the option of running the algorithms on simulators. However, the…

Quantum Physics · Physics 2022-05-04 Gian Giacomo Guerreschi

To efficiently implement many-qubit gates for use in quantum simulations on quantum computers we develop and present methods reexpressing exp[-i (H_1 + H_2 + ...) \Delta t] as a product of factors exp[-i H_1 \Delta t], exp[-i H_2 \Delta t],…

Quantum Physics · Physics 2009-10-31 A. T. Sornborger , E. D. Stewart

Quadratic programming over orthogonal matrices encompasses a broad class of hard optimization problems that do not have an efficient quantum representation. Such problems are instances of the little noncommutative Grothendieck problem…

Quantum Physics · Physics 2024-08-28 Andrew Zhao , Nicholas C. Rubin

Predictive design and optimization methods for controlled quantum systems depend on the accuracy of the system model. Any distortion of the input fields in an experimental platform alters the model accuracy and eventually disturbs the…

Quantum Physics · Physics 2023-06-29 Juhi Singh , Robert Zeier , Tommaso Calarco , Felix Motzoi

Quantum simulation has become a promising avenue of research that allows one to simulate and gain insight into the models of High Energy Physics whose experimental realizations are either complicated or inaccessible with current technology.…

High Energy Physics - Phenomenology · Physics 2023-08-01 S. Hasibul Hassan Chowdhury , Talal Ahmed Chowdhury , Salah Nasri , Omar Ibna Nazim , Shaikh Saad

In this paper, we develop a method for solving the problem of minimizing the $H^2$ error norm between the transfer functions of original and reduced systems on the set of stable matrices and two Euclidean spaces. That is, we develop a…

Optimization and Control · Mathematics 2018-08-03 Kazuhiro Sato

Quantum Hamiltonian identification is important for characterizing the dynamics of quantum systems, calibrating quantum devices and achieving precise quantum control. In this paper, an effective two-step optimization (TSO) quantum…

Quantum Physics · Physics 2018-06-05 Yuanlong Wang , Daoyi Dong , Bo Qi , Jun Zhang , Ian R. Petersen , Hidehiro Yonezawa

We propose an iterative algorithm to simulate the dynamics generated by any $n$-qubit Hamiltonian. The simulation entails decomposing the unitary time evolution operator $U$ (unitary) into a product of different time-step unitaries. The…

Quantum Physics · Physics 2012-04-09 Ashok Ajoy , Rama Koteswara Rao , Anil Kumar , Pranaw Rungta

We present efficient quantum circuits for fermionic excitation operators tailored for ion trap quantum computers exhibiting the M{\o}lmer-S{\o}rensen (MS) gate. Such operators commonly arise in the study of static and dynamic properties in…

Quantum Physics · Physics 2026-04-14 Thierry N. Kaldenbach , Erik Schultheis , Niklas Stewen , Gabriel Breuil

The recent literature on near-term applications for quantum computers contains several examples of the applications of hybrid quantum/classical variational approaches. This methodology can be applied to a variety of optimization problems,…

Quantum Physics · Physics 2019-01-23 Giacomo Nannicini

We present a quantum algorithm for simulating complex many-body systems and finding their ground states, combining the use of tensor networks and density matrix renormalization group (DMRG) techniques. The algorithm is based on von…

Quantum Physics · Physics 2026-03-06 Younes Javanmard

We show how to construct relevant families of matrix product operators in one and higher dimensions. Those form the building blocks for the numerical simulation methods based on matrix product states and projected entangled pair states. In…

Quantum Physics · Physics 2010-05-04 V. Murg , J. I. Cirac , B. Pirvu , F. Verstraete