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In this paper it is shown how the generating functional for Green's functions in relativistic quantum field theory and in thermal field theory can be evaluated in terms of a standard quantum mechanical path integral. With this calculational…

High Energy Physics - Theory · Physics 2011-07-19 D. G. C. McKeon , A. Rebhan

We present an algorithm to compute Green's functions on quantum computers for interacting electron systems, which is a challenging task on conventional computers. It uses a continued fraction representation based on the Lanczos method,…

Quantum Physics · Physics 2022-12-07 Francois Jamet , Abhishek Agarwal , Ivan Rungger

Quantum chemistry has been viewed as one of the potential early applications of quantum computing. Two techniques have been proposed for electronic structure calculations: (i) the variational quantum eigensolver and (ii) the…

Quantum Physics · Physics 2021-04-19 Christina Daniel , Diksha Dhawan , Dominika Zgid , James K. Freericks

We present a method to compute the many-body real-time Green's function using an adaptive variational quantum dynamics simulation approach. The real-time Green's function involves the time evolution of a quantum state with one additional…

Quantum Physics · Physics 2023-02-08 Niladri Gomes , David B. Williams-Young , Wibe A. de Jong

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

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

We study spectral properties of a non-Hermitian Hamiltonian describing a quantum particle propagating in a random imaginary scalar potential. Cast in the form of an effective field theory, we obtain an analytical expression for the ensemble…

Disordered Systems and Neural Networks · Physics 2009-10-31 A. V. Izyumov , B. D. Simons

The three key elements of a quantum simulation are state preparation, time evolution, and measurement. While the complexity scaling of time evolution and measurements are well known, many state preparation methods are strongly…

Quantum Physics · Physics 2022-03-24 Trevor Keen , Bo Peng , Karol Kowalski , Pavel Lougovski , Steven Johnston

We present a quantum-classical hybrid implementation of the Liouvillian recursion method to compute many-body Green's functions using a quantum computer. From an approximate ground state preparation circuit, this algorithm produces the…

Here we shall find the green's function of the difference equation of loop quantum cosmology. To illustrate how to use it, we shall obtain an iterative solution for closed model and evaluate its corresponding Bohmian trajectory.

General Relativity and Quantum Cosmology · Physics 2009-11-11 Fatimah Shojai , Ali Shojai

The many-body Green's function provides access to electronic properties beyond density functional theory level in ab inito calculations. In this manuscript, we propose a deep learning framework for predicting the finite-temperature Green's…

Chemical Physics · Physics 2024-02-20 Xinyang Dong , Emanuel Gull , Lei Wang

Imaginary time evolution is a powerful tool applied in quantum physics, while existing classical algorithms for simulating imaginary time evolution suffer high computational complexity as the quantum systems become larger and more complex.…

Quantum Physics · Physics 2022-10-12 Hao-Nan Xie , Shi-Jie Wei , Fan Yang , Zheng-An Wang , Chi-Tong Chen , Heng Fan , Gui-Lu Long

Quantum-classical hybrid algorithms are emerging as promising candidates for near-term practical applications of quantum information processors in a wide variety of fields ranging from chemistry to physics and materials science. We report…

One-body Green's function theories implemented on the real frequency axis offer a natural formalism for the unbiased theoretical determination of quasiparticle spectra in molecules and solids. Self-consistent Green's function methods…

Computational Physics · Physics 2015-05-22 Alicia Rae Welden , Jordan J. Phillips , Dominika Zgid

We obtain sufficient conditions for the efficient simulation of a continuous variable quantum algorithm or process on a classical computer. The resulting theorem is an extension of the Gottesman-Knill theorem to continuous variable quantum…

Quantum Physics · Physics 2007-05-23 Stephen D. Bartlett , Barry C. Sanders , Samuel L. Braunstein , Kae Nemoto

We show that cluster algorithms for quantum models have a meaning independent of the basis chosen to construct them. Using this idea, we propose a new method for measuring with little effort a whole class of Green's functions, once a…

Statistical Mechanics · Physics 2015-06-25 R. Brower , S. Chandrasekharan , U. -J. Wiese

The computational cost of exact methods for quantum simulation using classical computers grows exponentially with system size. As a consequence, these techniques can only be applied to small systems. By contrast, we demonstrate that quantum…

Quantum Physics · Physics 2008-12-17 Ivan Kassal , Stephen P. Jordan , Peter J. Love , Masoud Mohseni , Alán Aspuru-Guzik

Many phenomena of strongly correlated materials are encapsulated in the Fermi-Hubbard model whose thermodynamical properties can be computed from its grand canonical potential according to standard procedures. In general, there is no closed…

Quantum Physics · Physics 2016-03-09 Pierre-Luc Dallaire-Demers , Frank K. Wilhelm

We calculate eigenvalues of one-dimensional quantum-systems by the exact numerical solution of the Lippmann-Schwinger equation, analogous to the scattering problem. To illustrate our method, we treat elementary problems: the harmonic and…

Quantum Physics · Physics 2019-12-04 Alexander Jurisch

We propose quantum algorithms for projective ground-state preparation and calculations of the many-body Green's functions directly in frequency domain. The algorithms are based on the linear combination of unitary (LCU) operations and…

Quantum Physics · Physics 2021-12-13 Trevor Keen , Eugene Dumitrescu , Yan Wang