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Quantum computers must meet extremely stringent qualitative and quantitative requirements on their qubits in order to solve real-life problems. Quantum circuit fragmentation techniques divide a large quantum circuit into a number of…

Quantum Physics · Physics 2024-06-25 Saikat Basu , Arnav Das , Amit Saha , Amlan Chakrabarti , Susmita Sur-Kolay

We have developed an approach to calculate the single-particle Green function of a one-dimensional many-body system in the strongly localized limit at zero temperature. Our approach, based on the locator expansion, sums the contributions of…

Mesoscale and Nanoscale Physics · Physics 2017-05-05 A. N. Somoza , M. Ortuño , V. Gasparian , M. Pino

Numerically exact continuous-time Quantum Monte Carlo algorithm for finite fermionic systems with non-local interactions is proposed. The scheme is particularly applicable for general multi-band time-dependent correlations since it does not…

Strongly Correlated Electrons · Physics 2009-11-10 A. N. Rubtsov , A. I. Lichtenstein

A novel scheme to solve the quantum eigenvalue problem through the imaginary-time Green function Monte Carlo method is presented. This method is applicable to the excited states as well as to the ground state of a generic system. We…

Nuclear Theory · Physics 2008-11-26 Taksu Cheon

The Fermi-Hubbard model is of fundamental importance in condensed-matter physics, yet is extremely challenging to solve numerically. Finding the ground state of the Hubbard model using variational methods has been predicted to be one of the…

Quantum Physics · Physics 2021-01-04 Chris Cade , Lana Mineh , Ashley Montanaro , Stasja Stanisic

Quantum simulators have made a remarkable progress towards exploring the dynamics of many-body systems, many of which offer a formidable challenge to both theoretical and numerical methods. While state-of-the-art quantum simulators are in…

Understanding frictional phenomena is a fascinating fundamental problem with huge potential impact on energy saving. Such an understanding requires monitoring what happens at the sliding buried interface, which is almost inaccessible by…

Mesoscale and Nanoscale Physics · Physics 2023-04-24 Seiji Kajita , Alberto Pacini , Gabriele Losi , Nobuaki Kikkawa , Maria Clelia Righi

Quantum dynamics compilation is an important task for improving quantum simulation efficiency: It aims to synthesize multi-qubit target dynamics into a circuit consisting of as few elementary gates as possible. Compared to deterministic…

Quantum Physics · Physics 2024-09-26 Yuxuan Zhang , Roeland Wiersema , Juan Carrasquilla , Lukasz Cincio , Yong Baek Kim

High-order derivatives of Green's functions are a key ingredient in Taylor-based fast multipole methods, Barnes-Hut $n$-body algorithms, and quadrature by expansion (QBX). In these settings, derivatives underpin either the formation,…

Computational Engineering, Finance, and Science · Computer Science 2026-04-01 Hirish Chandrasekaran , Andreas Kloeckner

We extend the recently developed Quantum Quasi-Monte Carlo (QQMC) approach to obtain the full frequency dependence of Green functions in a single calculation. QQMC is a general approach for calculating high-order perturbative expansions in…

Strongly Correlated Electrons · Physics 2021-04-07 Corentin Bertrand , Daniel Bauernfeind , Philipp T. Dumitrescu , Marjan Maček , Xavier Waintal , Olivier Parcollet

We provide an in-depth examination of the $GW$ approximation of Green's function many-body perturbation theory by detailing both its theoretical and practical aspects in the realm of quantum chemistry. First, the quasiparticle context is…

Chemical Physics · Physics 2024-03-20 Antoine Marie , Abdallah Ammar , Pierre-François Loos

We study the many-body physics of different quantum systems using a hierarchy of correlations, which corresponds to a generalization of the $1/\mathcal{Z}$ hierarchy. The decoupling scheme obtained from this hierarchy is adapted to…

Strongly Correlated Electrons · Physics 2016-07-27 Álvaro Gómez-León

In this manuscript, we develop an efficient algorithm to evaluate the azimuthal Fourier components of the Green's function for the Helmholtz equation in cylindrical coordinates. A computationally efficient algorithm for this modal Green's…

Numerical Analysis · Mathematics 2022-10-05 James Garritano , Yuval Kluger , Vladimir Rokhlin , Kirill Serkh

Nonequilibrium time evolution of large quantum systems is a strong candidate for quantum advantage. Variational quantum algorithms have been put forward for this task, but their quantum optimization routines suffer from trainability and…

Quantum Physics · Physics 2024-07-12 Refik Mansuroglu , Felix Fischer , Michael J. Hartmann

Many applications of quantum computing in the near term rely on variational quantum circuits (VQCs). They have been showcased as a promising model for reaching a quantum advantage in machine learning with current noisy intermediate scale…

Quantum Physics · Physics 2022-10-25 Jonas Landman , Slimane Thabet , Constantin Dalyac , Hela Mhiri , Elham Kashefi

An acceleration of continuous time quantum Monte Carlo (CTQMC) methods is a potentially interesting branch of work as they are matchless as impurity solvers of a density functional theory in combination with a dynamical mean field theory…

Strongly Correlated Electrons · Physics 2019-08-07 Taegeun Song , Hunpyo Lee

The Gibbs partition function is an important quantity in describing statistical properties of a system in thermodynamic equilibrium. There are several proposals to calculate the partition functions on near-team quantum computers. However,…

The Green's function Monte Carlo (GFMC) method provides accurate solutions to the nuclear many-body problem and predicts properties of light nuclei starting from realistic two- and three-body interactions. Controlling the GFMC fermion-sign…

Nuclear Theory · Physics 2023-04-07 Gurtej Kanwar , Alessandro Lovato , Noemi Rocco , Michael Wagman

In this work we have presented a rather general and easy-to-apply method for discrete Hilbert space representation of quantum mechanical Green's operators. We have shown that if in some discrete Hilbert space basis representation the…

Quantum Physics · Physics 2016-09-08 Balázs Kónya

We present an adaptive variational quantum algorithm to estimate the Berry phase accumulated by a nondegenerate ground state under cyclic, adiabatic evolution of a time-dependent Hamiltonian. Our method leverages cyclic adiabatic evolution…

Quantum Physics · Physics 2026-02-09 Martin Mootz , Yong-Xin Yao
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