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This study introduces a systematic approach for analyzing strongly correlated systems by adapting the conventional quantum cluster method to a quantum circuit model. We have developed a more concise formula for calculating the cluster's…

Quantum Physics · Physics 2025-12-24 Hengyue Li , Yusheng Yang , Pin Lv , Jinglong Qu , Zhe-Hui Wang , Jian Sun , Shenggang Ying

Many-body Green's functions encode all the properties and excitations of interacting electrons. While these are challenging to be evaluated accurately on a classical computer, recent efforts have been directed towards finding quantum…

We reformulate the Lanczos algorithm for quantum wave function propagation in terms of variational principle. By including some basis states of previous time steps into the variational subspace, the resultant accuracy increases by several…

Quantum Physics · Physics 2009-11-13 Quanlin Jie , Dunhuan Liu

We report on a quantum-classical simulation of the single-band Hubbard model using two-site dynamical mean-field theory (DMFT). Our approach uses IBM's superconducting qubit chip to compute the zero-temperature impurity Green's function in…

Quantum Physics · Physics 2021-11-11 Trevor Keen , Thomas Maier , Steven Johnston , Pavel Lougovski

In this work we investigate methods to improve the efficiency and scalability of quantum algorithms for quantum chemistry applications. We propose a transformation of the electronic structure Hamiltonian in the second quantization framework…

Quantum computers offer the potential to efficiently simulate the dynamics of quantum systems, a task whose difficulty scales exponentially with system size on classical devices. To assess the potential for near-term quantum computers to…

Quantum Physics · Physics 2023-07-06 Nathan M. Myers , Ryan Scott , Kwon Park , Vito W. Scarola

In the framework of the hybrid quantum-classical variational cluster approach (VCA) to strongly correlated electron systems one of the goals of a quantum subroutine is to find single-particle correlation functions of lattice fermions in…

Quantum Physics · Physics 2025-06-26 Gino Bishop , Dmitry Bagrets , Frank K. Wilhelm

We propose an improved quantum algorithm to calculate the Green's function through real-time propagation, and use it to compute the retarded Green's function for the 2-, 3- and 4-site Hubbard models. This novel protocol significantly…

Quantum Physics · Physics 2022-10-21 Francesco Libbi , Jacopo Rizzo , Francesco Tacchino , Nicola Marzari , Ivano Tavernelli

Numerical linked-cluster expansions allow one to calculate finite-temperature properties of quantum lattice models directly in the thermodynamic limit through exact solutions of small clusters. However, full diagonalization is often the…

Strongly Correlated Electrons · Physics 2019-07-17 Krishnakumar Bhattaram , Ehsan Khatami

In designing quantum control, it is generally required to simulate the controlled system evolution with a classical computer. However, computing the time evolution operator can be quite resource-consuming since the total Hamiltonian is…

Quantum Physics · Physics 2022-10-25 Xiaodong Yang , Xinfang Nie , Yunlan Ji , Tao Xin , Dawei Lu , Jun Li

We propose a scheme for the construction of one-particle Green's function (GF) of an interacting electronic system via statistical sampling on a quantum computer. Although the non-unitarity of creation and annihilation operators for the…

Quantum Physics · Physics 2020-02-19 Taichi Kosugi , Yu-ichiro Matsushita

We propose an algorithm to obtain Green's functions as a continued fraction on quantum computers, which is based on the construction of the Krylov basis using variational quantum algorithms, and included in a Lanczos iterative scheme. This…

Quantum Physics · Physics 2021-08-27 Francois Jamet , Abhishek Agarwal , Carla Lupo , Dan E. Browne , Cedric Weber , Ivan Rungger

Determining low-energy eigenstates in electronic many-body quantum systems is a key challenge in computational chemistry and condensed-matter physics. Hybrid quantum-classical approaches, such as the Variational Quantum Eigensolver and…

Quantum Physics · Physics 2025-10-27 Hamzat A. Akande , Alexandre Perrin , Bruno Senjean , Matthieu Saubanere

The single particle Green's function provides valuable information on the momentum and energy-resolved spectral properties for a strongly correlated system. In large-scale numerical calculations using quantum Monte Carlo (QMC), dynamical…

Strongly Correlated Electrons · Physics 2024-10-01 Maksymilian Kliczkowski , Lauren Keyes , Sayantan Roy , Thereza Paiva , Mohit Randeria , Nandini Trivedi , Maciej M. Maska

The Green's function has been an indispensable tool to study many-body systems that remain one of the biggest challenges in modern quantum physics for decades. The complicated calculation of Green's function impedes the research of…

Quantum Physics · Physics 2022-05-04 Jie Zhu , Yuya O. Nakagawa , Chuan-Feng Li , Guang-Can Guo , Yong-Sheng Zhang

We present a quantum Monte-Carlo algorithm for computing the perturbative expansion in power of the coupling constant $U$ of the out-of-equilibrium Green's functions of interacting Hamiltonians of fermions. The algorithm extends the one…

Strongly Correlated Electrons · Physics 2019-09-23 Corentin Bertrand , Olivier Parcollet , Antoine Maillard , Xavier Waintal

Models of interacting many-body quantum systems that may realize new exotic phases of matter, notably quantum spin liquids, are challenging to study using even state-of-the-art classical methods such as tensor network simulations. Quantum…

Quantum Physics · Physics 2025-04-16 Aaron Szasz , Ed Younis , Wibe Albert de Jong

The nonequilibrium Green's function formalism provides a versatile and powerful framework for numerical studies of nonequilibrium phenomena in correlated many-body systems. For calculations starting from an equilibrium initial state, a…

Strongly Correlated Electrons · Physics 2024-07-11 Matthias Murray , Hiroshi Shinaoka , Philipp Werner

Understanding the dynamics of quantum systems is crucial in many areas of physics, but simulating many-body systems presents significant challenges due to the large Hilbert space to navigate and the exponential growth of computational…

Quantum Physics · Physics 2025-03-14 Sangjin Lee , Youngseok Kim , Seung-Woo Lee

We present and benchmark quantum computing approaches for calculating real-time single-particle Green's functions and nonlinear susceptibilities of Hamiltonian systems. The approaches leverage adaptive variational quantum algorithms for…

Quantum Physics · Physics 2025-11-17 Martin Mootz , Thomas Iadecola , Yong-Xin Yao