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We present a quantum algorithm for simulating rovibrational Hamiltonians on fault-tolerant quantum computers. The method integrates exact curvilinear kinetic energy operators and general-form potential energy surfaces expressed in a hybrid…

Quantum Physics · Physics 2026-04-07 Michał Szczepanik , Ákos Nagy , Emil Żak

Simulating high-weight Hamiltonians can convert local noise on the original Hamiltonian into undesirable nonlocal noise on the simulated Hamiltonian. Here we show how starting from two-local Hamiltonian in the presence of non-Markovian…

Quantum Physics · Physics 2017-11-29 Milad Marvian , Todd Brun , Daniel A. Lidar

Simulating the unitary dynamics of a quantum system is a fundamental problem of quantum mechanics, in which quantum computers are believed to have significant advantage over their classical counterparts. One prominent such instance is the…

Quantum Physics · Physics 2024-09-04 John M. Martyn , Yuan Liu , Zachary E. Chin , Isaac L. Chuang

We propose a universal approach based on Hamiltonian inverse engineering to realize a set of parameterized two-qubit gates. This method possesses unique advantages to simultaneous control of transitions among four energy levels, providing a…

Quantum Physics · Physics 2026-03-06 Yang-Yang Yu , Guang-Hui Zhang , Yan-Jie He , Jun Wu , Xue-Ke Song , Dong Wang

Hamiltonian simulation is one of the most important problems in quantum computation, and quantum singular value transformation (QSVT) is an efficient way to simulate a general class of Hamiltonians. However, the QSVT circuit typically…

Quantum Physics · Physics 2023-05-15 Yulong Dong , K. Birgitta Whaley , Lin Lin

We present an algorithm for sparse Hamiltonian simulation whose complexity is optimal (up to log factors) as a function of all parameters of interest. Previous algorithms had optimal or near-optimal scaling in some parameters at the cost of…

Quantum Physics · Physics 2016-01-06 Dominic W. Berry , Andrew M. Childs , Robin Kothari

Quantum simulation is a foundational application for quantum computers, projected to offer insights into complex quantum systems beyond the reach of classical computation. However, with the exception of Trotter-based methods, which suffer…

Quantum Physics · Physics 2026-02-10 Amir Kalev , Itay Hen

The physics of a closed quantum mechanical system is governed by its Hamiltonian. However, in most practical situations, this Hamiltonian is not precisely known, and ultimately all there is are data obtained from measurements on the system.…

We study the problem of learning a Hamiltonian $H$ to precision $\varepsilon$, supposing we are given copies of its Gibbs state $\rho=\exp(-\beta H)/\operatorname{Tr}(\exp(-\beta H))$ at a known inverse temperature $\beta$. Anshu,…

Quantum Physics · Physics 2025-10-14 Jeongwan Haah , Robin Kothari , Ewin Tang

We study the problem of learning a $k$-body Hamiltonian with $M$ unknown Pauli terms that are not necessarily geometrically local. We propose a protocol that learns the Hamiltonian to precision $\epsilon$ with total evolution time…

Quantum Physics · Physics 2024-12-13 Muzhou Ma , Steven T. Flammia , John Preskill , Yu Tong

The required precision to perform quantum simulations beyond the capabilities of classical computers imposes major experimental and theoretical challenges. The key to solving these issues are precise means of characterizing analog quantum…

Quantum Physics · Physics 2024-11-11 Dominik Hangleiter , Ingo Roth , Jonas Fuksa , Jens Eisert , Pedram Roushan

Non-autonomous dynamical systems appear in a very wide range of interesting applications, both in classical and quantum dynamics, where in the latter case it corresponds to having a time-dependent Hamiltonian. However, the quantum…

Quantum Physics · Physics 2025-04-22 Yu Cao , Shi Jin , Nana Liu

We propose an efficient quantum algorithm for simulating the dynamics of general Hamiltonian systems. Our technique is based on a power series expansion of the time-evolution operator in its off-diagonal terms. The expansion decouples the…

Quantum Physics · Physics 2021-06-22 Amir Kalev , Itay Hen

Learning the Hamiltonian governing a quantum system is a central task in quantum metrology, sensing, and device characterization. Existing Heisenberg-limited Hamiltonian learning protocols either require multi-qubit operations that are…

Quantum Physics · Physics 2026-01-16 Shrigyan Brahmachari , Shuchen Zhu , Iman Marvian , Yu Tong

The capacity to custom tailor the properties of quantum matter and materials is a central requirement for enlarging their range of possible functionalities. A particularly promising route is the use of driving protocols to engineer specific…

Quantum Physics · Physics 2025-02-19 Zhanpeng Fu , Roderich Moessner , Hongzheng Zhao , Marin Bukov

Reconstructing the Hamiltonian of a quantum system is an essential task for characterizing and certifying quantum processors and simulators. Existing techniques either rely on projective measurements of the system before and after coherent…

We present a general method to efficiently design optimal control sequences for non-Markovian open quantum systems, and illustrate it by optimizing the shape of a laser pulse to prepare a quantum dot in a specific state. The optimization of…

Quantum Physics · Physics 2023-07-11 Gerald E. Fux , Eoin P. Butler , Paul R. Eastham , Brendon W. Lovett , Jonathan Keeling

We study how parallelism can speed up quantum simulation. A parallel quantum algorithm is proposed for simulating the dynamics of a large class of Hamiltonians with good sparse structures, called uniform-structured Hamiltonians, including…

Quantum Physics · Physics 2024-01-17 Zhicheng Zhang , Qisheng Wang , Mingsheng Ying

Hamiltonian simulation is one of the most important problems in the field of quantum computing. There have been extended efforts on designing algorithms for faster simulation, and the evolution time $T$ for the simulation turns out to…

Quantum Physics · Physics 2023-05-23 Nai-Hui Chia , Kai-Min Chung , Yao-Ching Hsieh , Han-Hsuan Lin , Yao-Ting Lin , Yu-Ching Shen

We propose a new variational quantum algorithm, which we refer to as TIMES-ADAPT, that prepares time-evolved states in a low-energy or symmetric subspace of a time-independent Hamiltonian on a quantum computer. Using a specially trained…