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Many-body perturbation theory methods, such as the $G_0W_0$ approximation, are able to accurately predict quasiparticle (QP) properties of several classes of materials. However, the calculation of the QP band structure of two-dimensional…

Materials Science · Physics 2022-06-23 Alberto Guandalini , Pino D'Amico , Andrea Ferretti , Daniele Varsano

Overlap between two neural quantum states can be computed through Monte Carlo sampling by evaluating the unnormalized probability amplitudes on a subset of basis configurations. Due to the presence of probability amplitude ratios in the…

Quantum Physics · Physics 2023-11-28 Tomasz Szołdra

We computed the Compton profile of solid and liquid lithium using quantum Monte Carlo (QMC) and compared with recent experimental measurements obtaining good agreement. Importantly, we find it crucial to account for proper core-valence…

Materials Science · Physics 2020-04-24 Yubo Yang , Nozomu Hiraoka , Kazuhiro Matsuda , Markus Holzmann , David M. Ceperley

We study the electronic excitation spectra in solid molecular hydrogen (phase I) at ambient temperature and 5-90 GPa pressures using Quantum Monte Carlo methods and Many-Body Perturbation Theory. In this range, the system changes from a…

Materials Science · Physics 2024-05-21 Vitaly Gorelov , Markus Holzmann , David M. Ceperley , Carlo Pierleoni

We present an approach based on density-functional theory for the calculation of fundamental gaps of both finite and periodic two-dimensional (2D) electronic systems. The computational cost of our approach is comparable to that of total…

Materials Science · Physics 2021-08-11 Alberto Guandalini , Alice Ruini , Esa Räsänen , Carlo Andrea Rozzi , Stefano Pittalis

We study the efficiency, precision and accuracy of all-electron variational and diffusion quantum Monte Carlo calculations using Slater basis sets. Starting from wave functions generated by Hartree-Fock and density functional theory, we…

Materials Science · Physics 2010-02-11 Norbert Nemec , Michael D. Towler , R. J. Needs

We study the accuracy of the divide-and-conquer method for electronic structure calculations. The analysis is conducted for a prototypical subdomain problem in the method. We prove that the pointwise difference between electron densities of…

Numerical Analysis · Mathematics 2015-04-07 Jingrun Chen , Jianfeng Lu

Certain point defects in solids can efficiently be used as qubits for applications in quantum technology. They have spin states that are initializable, readable, robust, and can be manipulated optically. New theoretical methods are needed…

Computational Physics · Physics 2023-09-20 Kristoffer Simula , Ilja Makkonen

We present an approach to studying optical band gaps in real solids in which quantum Monte Carlo methods allow for the application of a rigorous variational principle to both ground and excited state wave functions. In tests that include…

Strongly Correlated Electrons · Physics 2019-07-24 Luning Zhao , Eric Neuscamman

The quasiparticle effective mass is a key quantity in the physics of electron gases, describing the renormalization of the electron mass due to electron-electron interactions. Two-dimensional electron gases are of fundamental importance in…

Quantum Gases · Physics 2013-02-01 N. D. Drummond , R. J. Needs

The combination of continuum Many-Body Quantum physics and Monte Carlo methods provide a powerful and well established approach to first principles calculations for large systems. Replacing the exact solution of the problem with a…

Computational Physics · Physics 2009-10-01 J. R. Trail

The origin of the pseudogap behavior, found in many high-$T_c$ superconductors, remains one of the greatest puzzles in condensed matter physics. One possible mechanism is fermionic incoherence, which near a quantum critical point allows…

Strongly Correlated Electrons · Physics 2022-05-16 Weilun Jiang , Yuzhi Liu , Avraham Klein , Yuxuan Wang , Kai Sun , Andrey V. Chubukov , Zi Yang Meng

We use a variational Monte Carlo algorithm to solve the electronic structure of two-dimensional semiconductor quantum dots in external magnetic field. We present accurate many-body wave functions for the system in various magnetic field…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Ari Harju

Standard quantum amplitude estimation algorithms provide quadratic speedup to Monte-Carlo simulations but require a circuit depth that scales as inverse of the estimation error. In view of the shallow depth in near-term devices, the…

Quantum Physics · Physics 2024-10-03 Dinh-Long Vu , Bin Cheng , Patrick Rebentrost

The fixed node diffusion Monte Carlo (DMC) method has attracted interest in recent years as a way to calculate properties of solid materials with high accuracy. However, the framework for the calculation of properties such as total…

Materials Science · Physics 2016-01-20 Jaehyung Yu , Lucas K. Wagner , Elif Ertekin

Quantum Monte Carlo methods provide in principle an accurate treatment of the many-body problem of the ground and excited states of condensed systems. In practice, however, uncontrolled errors such as those arising from the fixed-node and…

Materials Science · Physics 2012-03-27 William W. Tipton , Neil D. Drummond , Richard G. Hennig

\textit{Ab initio} quantum Monte Carlo (QMC) methods in principle allow for the calculation of exact properties of correlated many-electron systems, but are in general limited to the simulation of a finite number of electrons $N$ in…

Statistical Mechanics · Physics 2021-04-21 Tobias Dornheim , Jan Vorberger

We present real space quantum Monte Carlo (QMC) calculations of the scandate LaScO$_3$ that proved to be challenging for traditional electronic structure approaches due to strong correlation effects resulting in inaccurate band gaps from…

Materials Science · Physics 2020-07-08 Cody A. Melton , Lubos Mitas

Quantum error mitigation (QEM) is a class of promising techniques for reducing the computational error of variational quantum algorithms. In general, the computational error reduction comes at the cost of a sampling overhead due to the…

Quantum Physics · Physics 2022-01-21 Yifeng Xiong , Soon Xin Ng , Lajos Hanzo

Quantum mechanics for many-body systems may be reduced to the evaluation of integrals in 3N dimensions using Monte-Carlo, providing the Quantum Monte Carlo ab initio methods. Here we limit ourselves to expectation values for trial…

Computational Physics · Physics 2010-11-22 John Robert Trail , Ryo Maezono