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While the treatment of chemically relevant systems containing hundreds or even thousands of electrons remains beyond the reach of quantum devices, the development of quantum-classical hybrid algorithms to resolve electronic correlation…

A state-preserving quantum counting algorithm is used to obtain coefficients of a Lanczos recursion from a single ground state wavefunction on the quantum computer. This is used to compute the continued fraction representation of an…

Quantum Physics · Physics 2021-03-10 Thomas E. Baker

The use of near-term quantum devices that lack quantum error correction, for addressing quantum chemistry and physics problems, requires hybrid quantum-classical algorithms and techniques. Here we present a process for obtaining the…

Quantum Physics · Physics 2023-08-14 Pejman Jouzdani , Stefan Bringuier

We address the question of how a quantum computer can be used to simulate experiments on quantum systems in thermal equilibrium. We present two approaches for the preparation of the equilibrium state on a quantum computer. For both…

Quantum Physics · Physics 2009-10-31 Barbara M. Terhal , David P. DiVincenzo

The eigenvalue-function pair of the 3D Schr\"odinger equation can be efficiently computed by use of high order, imaginary time propagators. Due to the diffusion character of the kinetic energy operator in imaginary time, algorithms…

Materials Science · Physics 2009-11-13 Siu A. Chin , S. Janecek , E. Krotscheck

Quantum chemistry applications on quantum computers currently rely heavily on the variational quantum eigensolver (VQE) algorithm. This hybrid quantum-classical algorithm aims at finding ground state solutions of molecular systems based on…

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 derive equations of motion for Green's functions of the multi-orbital Anderson impurity model by differentiating symmetrically with respect to all time arguments. The resulting equations relate the one- and two-particle Green's function…

Strongly Correlated Electrons · Physics 2019-08-14 Josef Kaufmann , Patrik Gunacker , Alexander Kowalski , Giorgio Sangiovanni , Karsten Held

A new method for non-perturbative calculation of Green functions in quantum mechanics and quantum field theory is proposed. The method is based on an approximation of Schwinger-Dyson equation for the generating functional by exactly soluble…

High Energy Physics - Theory · Physics 2008-11-26 V. E. Rochev

The decay properties of the one-particle Green function in real space and imaginary time are systematically studied for solids. I present an analytic solution for the homogeneous electron gas at finite and at zero temperature as well as…

Materials Science · Physics 2007-05-23 Arno Schindlmayr

We present an algorithm for measurement of the Green's function in the hybridization expansion continuous-time quantum Monte-Carlo based on continuous estimators. Compared to the standard method, the present algorithm has similar or better…

Strongly Correlated Electrons · Physics 2013-06-17 Pavel Augustinský , Jan Kuneš

The Grassmann time-evolving matrix product operator method has shown great potential as a general-purpose quantum impurity solver, as its numerical errors can be well-controlled and it is flexible to be applied on both the imaginary- and…

Strongly Correlated Electrons · Physics 2025-10-08 Zhijie Sun , Ruofan Chen , Zhenyu Li , Chu Guo

We develop a Monte Carlo sampling algorithm to numerically evaluate the Lehmann representation for the finite temperature single-particle Green's function in the repulsive Lieb-Liniger model. This allows us to determine the spectral…

Statistical Mechanics · Physics 2026-05-20 Riccardo Senese , Fabian H. L. Essler

We compute the partition function of an anyon-like harmonic oscillator. The well known results for both the bosonic and fermionic oscillators are then reobtained as particular cases as ours. The technique we employ is a non-relativistic…

High Energy Physics - Theory · Physics 2009-10-28 H. Boschi-Filho , C. Farina , A. de Souza Dutra

The calculation of imaginary time displaced correlation functions with the auxiliary field projector quantum Monte-Carlo algorithm provides valuable insight (such as spin and charge gaps) in the model under consideration. One of the authors…

Strongly Correlated Electrons · Physics 2009-10-31 M. Feldbacher , F. F. Assaad

The procedure for simulating the nuclear magnetic resonance spectrum linked to the spin system of a molecule for a certain nucleus entails diagonalizing the associated Hamiltonian matrix. As the dimensions of said matrix grow exponentially…

Quantum Physics · Physics 2024-10-29 Joaquín Ossorio-Castillo , Alexandre Rodríguez-Coello

The basic mathematical properties of Green's functions used in statistical mechanics as well as the equations defining these functions and the techniques of solving these equations are reviewed. An approach is presented called the…

Statistical Mechanics · Physics 2007-05-23 V. I. Yukalov

Considering recent advancements and successes in the development of efficient quantum algorithms for electronic structure calculations --- alongside impressive results using machine learning techniques for computation --- hybridizing…

Quantum Physics · Physics 2018-10-24 Rongxin Xia , Sabre Kais

Using the tensor product representation in the density matrix renormalization group, we show that a quantum circuit of Grover's algorithm, which has one-qubit unitary gates, generalized Toffoli gates, and projective measurements, can be…

Quantum Physics · Physics 2007-05-23 A. Kawaguchi , K. Shimizu , Y. Tokura , N. Imoto

We introduce a hybrid classical-quantum algorithm for simulating a Hamiltonian of the form $H= \sum_{i=1}^K H_i = \sum_{i=1}^K H_{i_1} \otimes H_{i_2} \otimes \cdots \otimes H_{i_M}$. Given that the entries of all $\{ H_{i_1}, H_{i_2} ,…

Quantum Physics · Physics 2026-04-08 Nhat A. Nghiem , Tzu-Chieh Wei
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