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Phase estimation is known to be a robust method for single-qubit gate calibration in quantum computers, while Bayesian estimation is widely used in devising optimal methods for learning in quantum systems. We present Bayesian phase…

Quantum Physics · Physics 2025-05-06 Brennan de Neeve , Andrey V. Lebedev , Vlad Negnevitsky , Jonathan P. Home

A new basis adaptive algorithm for hybrid quantum-classical platforms is introduced to efficiently find the ground-state (gs) properties of quantum many-body systems. The method addresses limitations of many algorithms, such as Variational…

Strongly Correlated Electrons · Physics 2025-12-16 Anutosh Biswas , Sayan Ghosh , Ritajit Majumdar , Mostafizur Rahaman , Manoranjan Kumar

Using the Kadanoff-Baym non-equilibrium Green's function formalism, we derive kinetic equations for the non-condensate atoms at finite temperatures which include the effect of binary collisions between atoms. The effect of collisions is…

Condensed Matter · Physics 2017-08-23 Milena Imamovic-Tomasovic , Allan Griffin

Determining the properties of molecules and materials is one of the premier applications of quantum computing. A major question in the field is: how might we use imperfect near-term quantum computers to solve problems of practical value? We…

Quantum Physics · Physics 2023-08-29 Phillip W. K. Jensen , Peter D. Johnson , Alexander A. Kunitsa

We first rewrite the perturbation expansion of the time evolution operator [An Min Wang, quant-ph/0611216] in a form as concise as possible. Then we derive out the perturbation expansion of the time-dependent complete Green operator and…

Quantum Physics · Physics 2007-05-23 An Min Wang

We use the Kadanoff-Baym equations within the framework of many-body perturbation theory to study the double occupancies in a Hubbard dimer. The double occupancies are obtained from the equations of motion of the single-particle Green's…

Strongly Correlated Electrons · Physics 2010-09-16 M. Puig von Friesen , C. Verdozzi , C. -O. Almbladh

Green's function methods lead to ab initio, systematically improvable simulations of molecules and materials while providing access to multiple experimentally observable properties such as the density of states and the spectral function.…

Quantum Physics · Physics 2023-09-19 Diksha Dhawan , Dominika Zgid , Mario Motta

It is well known that second order linear ordinary differential equations with slowly varying coefficients admit slowly varying phase functions. This observation is the basis of the Liouville-Green method and many other techniques for the…

Numerical Analysis · Mathematics 2022-12-19 James Bremer

The objective of this paper is to describe a simple phenomenological approach for including incoherent dephasing processes in quantum transport models. The presented illustrative numerical results show this model provides the flexibility of…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Roksana Golizadeh-Mojarad , Supriyo Datta

The Green's function plays a crucial role when studying the nature of quantum many-body systems, especially strongly-correlated systems. Although the development of quantum computers in the near future may enable us to compute energy…

Quantum Physics · Physics 2020-08-25 Suguru Endo , Iori Kurata , Yuya O. Nakagawa

We present an infinite Grassmann time-evolving matrix product operator method for quantum impurity problems, which directly works in the steady state. The method embraces the well-established infinite matrix product state algorithms with…

Strongly Correlated Electrons · Physics 2024-08-09 Chu Guo , Ruofan Chen

We present an ongoing development of an existing code for calculating ground-state, steady-state, and transient properties of many-particle systems. The development involves the addition of the full four-index two electron integrals, which…

Mesoscale and Nanoscale Physics · Physics 2016-05-04 Richard A. Lynn , Robert van Leeuwen

In this paper we study Green measures for certain classes of random time change Markov processes where the random time change are inverse subordinators. We show the existence of the Green measure for these processes under the condition of…

Probability · Mathematics 2020-08-11 José L. da Silva , Yuri Kondratiev

The theoretical investigation of charge (and spin) transport at nanometer length scales requires the use of advanced and powerful techniques able to deal with the dynamical properties of the relevant physical systems, to explicitly include…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 D. A. Ryndyk , R. Gutierrez , B. Song , G. Cuniberti

Realisation of experiments even on small and medium-scale quantum computers requires an optimisation of several parameters to achieve high-fidelity operations. As the size of the quantum register increases, the characterisation of quantum…

Quantum Physics · Physics 2020-08-11 F. Martínez-García , D. Vodola , M. Müller

Time-dependent quantum mechanics provides an intuitive picture of particle propagation in external fields. Semiclassical methods link the classical trajectories of particles with their quantum mechanical propagation. Many analytical results…

Mesoscale and Nanoscale Physics · Physics 2008-03-07 Tobias Kramer , Eric J. Heller , Robert E. Parrott

We derive equations of motion for higher order density response functions using the theory of thermodynamic Green's functions. We also derive expressions for the higher order generalized dielectric functions and polarization functions.…

Strongly Correlated Electrons · Physics 2024-10-04 Jan Vorberger , Tobias Dornheim , Maximilian P. Böhme , Zhandos Moldabekov , Panagiotis Tolias

We present a simple algorithm to switch between $N$-body time integrators in a reversible way. We apply it to planetary systems undergoing arbitrarily close encounters and highly eccentric orbits, but the potential applications are broader.…

Earth and Planetary Astrophysics · Physics 2023-03-08 David M. Hernandez , Walter Dehnen

Neural operators are a popular technique in scientific machine learning to learn a mathematical model of the behavior of unknown physical systems from data. Neural operators are especially useful to learn solution operators associated with…

Numerical Analysis · Mathematics 2022-08-05 Nicolas Boullé , Seick Kim , Tianyi Shi , Alex Townsend

In this paper, we present a quantum computational method to calculate the many-body Green's function matrix in a spin orbital basis. We apply our approach to finite-sized fermionic Hubbard models and related impurity models within Dynamical…