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In this work, we study the Hamiltonian Decoded Quantum Interferometry (HDQI) for the general Hamiltonians $H=\sum_ic_iP_i$ on an $n$-qubit system, where the coefficients $c_i\in \mathbb{R}$ and $P_i$ are Pauli operators. We show that, given…

Quantum Physics · Physics 2026-01-27 Kaifeng Bu , Weichen Gu , Xiang Li

In this work, we give a polynomial-time quantum algorithm for solving the ground states of a class of classically hard Hamiltonians. The mechanism of the exponential speedup that appeared in our algorithm comes from dissipation in open…

Quantum Physics · Physics 2024-11-13 Zhong-Xia Shang , Zi-Han Chen , Chao-Yang Lu , Jian-Wei Pan , Ming-Cheng Chen

The Markov property entails the conditional independence structure inherent in Gibbs distributions for general classical Hamiltonians, a feature that plays a crucial role in inference, mixing time analysis, and algorithm design. However,…

Quantum Physics · Physics 2025-04-04 Chi-Fang Chen , Cambyse Rouzé

The partition function of a relativistic invariant quantum field theory is expressed by its vacuum energy calculated on a spatial manifold with one dimension compactified to a 1-sphere $S^1 (\beta)$, whose circumference $\beta$ represents…

High Energy Physics - Theory · Physics 2016-08-31 Hugo Reinhardt

Traditional computational methods for studying quantum many-body systems are "forward methods," which take quantum models, i.e., Hamiltonians, as input and produce ground states as output. However, such forward methods often limit one's…

Strongly Correlated Electrons · Physics 2018-07-31 Eli Chertkov , Bryan K. Clark

We propose a method based on deep reinforcement learning that efficiently prepares a quantum many-body pure state in thermal or prethermal equilibrium. The main physical intuition underlying the method is that the information on the…

Quantum Physics · Physics 2023-01-30 Shotaro Z. Baba , Nobuyuki Yoshioka , Yuto Ashida , Takahiro Sagawa

Characterizing the entanglement structure of ground states of local Hamiltonians is a fundamental problem in quantum information. In this work we study the computational complexity of this problem, given the Hamiltonian as input. Our main…

Quantum Physics · Physics 2024-11-08 Adam Bouland , Chenyi Zhang , Zixin Zhou

Quantum algorithms for probing ground-state properties of quantum systems require good initial states. Projection-based methods such as eigenvalue filtering rely on inputs that have a significant overlap with the low-energy subspace, which…

Quantum Physics · Physics 2024-04-10 Danial Motlagh , Modjtaba Shokrian Zini , Juan Miguel Arrazola , Nathan Wiebe

Variational quantum algorithms are a promising tool for solving partial differential equations. The standard approach for its numerical solution are finite difference schemes, which can be reduced to the linear algebra problem. We consider…

Quantum Physics · Physics 2023-10-10 N. M. Guseynov , A. A. Zhukov , W. V. Pogosov , A. V. Lebedev

Due to the limitations of present-day quantum hardware, it is especially critical to design algorithms that make the best possible use of available resources. When simulating quantum many-body systems on a quantum computer, straightforward…

Quantum Physics · Physics 2021-04-07 Olivia Di Matteo , Anna McCoy , Peter Gysbers , Takayuki Miyagi , R. M. Woloshyn , Petr Navrátil

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

This work provides a rigorous and self-contained introduction to numerical methods for Hamiltonian simulation in quantum computing, with a focus on high-order product formulas for efficiently approximating the time evolution of quantum…

Quantum Physics · Physics 2025-07-16 Javier Lopez-Cerezo

Quantum entanglement is considered, by and large, to be a very delicate and non-robust phenomenon that is very hard to maintain in the presence of noise, or non-zero temperatures. In recent years however, and motivated, in part, by a quest…

Quantum Physics · Physics 2017-02-27 Lior Eldar

Identifying Hamiltonian of a quantum system is of vital importance for quantum information processing. In this Letter, we realized and benchmarked a quantum Hamiltonian identification algorithm recently proposed [Phys. Rev. Lett.…

Quantum Physics · Physics 2014-10-16 Shi-yao Hou , Hang Li , Gui-Lu Long

A translation-invariant gapped local Hamiltonian is in the trivial phase if it can be connected to a completely decoupled Hamiltonian with a smooth path of translation-invariant gapped local Hamiltonians. For the ground state of such a…

Strongly Correlated Electrons · Physics 2020-01-30 Yichen Huang

Identifying unknown Hamiltonians from their quantum dynamics is a pivotal challenge in quantum technologies. In this paper, we introduce Hamiltonian recognition, a framework that bridges quantum hypothesis testing and quantum metrology,…

Quantum Physics · Physics 2026-02-26 Chengkai Zhu , Shuyu He , Yu-Ao Chen , Lei Zhang , Xin Wang

Reconstructing Hamiltonians from local measurements is key to enabling reliable quantum simulation: both validating the implemented model, and identifying any left-over terms with sufficient precision is a problem of increasing importance.…

Quantum Physics · Physics 2024-07-09 Sourav Nandy , Markus Schmitt , Marin Bukov , Zala Lenarčič

We study necessary conditions for the efficient simulation of both bipartite and multipartite Hamiltonians, which are independent of the eigenvalues and based on the algebraic-geometric invariants introduced in [1-2]. Our results indicate…

Quantum Physics · Physics 2007-05-23 Hao Chen

A fundamental problem in quantum many-body physics is that of finding ground states of local Hamiltonians. A number of recent works gave provably efficient machine learning (ML) algorithms for learning ground states. Specifically, [Huang et…

A novel approach to the Hamiltonian formulation of quantum field theory at finite temperature is presented. The temperature is introduced by compactification of a spatial dimension. The whole finite-temperature theory is encoded in the…

High Energy Physics - Theory · Physics 2018-11-09 Hugo Reinhardt , Davide Campagnari , Markus Quandt