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We derive a closed equation of motion for the one particle density matrix of a quantum system coupled to multiple baths using the Redfield master equation combined with a mean-field approximation. The steady-state solution may be found…

Mesoscale and Nanoscale Physics · Physics 2020-09-30 Zekun Zhuang , Jaime Merino , J. B. Marston

A method based on separated integration to estimate anharmonic corrections to energy and vibration of molecules in a second-order diagrammatic vibrational many-body Green's function formalism has already been presented. A severe bottleneck…

Chemical Physics · Physics 2019-09-17 Prashant Rai , Khachik Sargsyan , Habib Najm , So Hirata

The performance potential for simulating quantum electron transport on graphical processing units (GPUs) is studied. Using graphene ribbons of realistic sizes as an example it is shown that GPUs provide significant speed-ups in comparison…

Computational Physics · Physics 2012-06-22 S. Ihnatsenka

Numerical utilities of the Contact Block Reduction (CBR) method in evaluating the retarded Green's function, are discussed for 3-D multi-band open systems that are represented by the atomic tight-binding (TB) and continuum k\cdotp (KP) band…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 Hoon Ryu , Hong-Hyun Park , Mincheol Shin , Dragica Vasileska , Gerhard Klimeck

Learning the Green's function using deep learning models enables to solve different classes of partial differential equations. A practical limitation of using deep learning for the Green's function is the repeated computationally expensive…

Machine Learning · Computer Science 2023-08-02 Kishan Wimalawarne , Taiji Suzuki , Sophie Langer

Quantum optimization as a field has largely been restricted by the constraints of current quantum computing hardware, as limitations on size, performance, and fidelity mean most non-trivial problem instances won't fit on quantum devices.…

Quantum Physics · Physics 2024-05-03 Ibrahim Cameron , Teague Tomesh , Zain Saleem , Ilya Safro

In [3], the authors used the Legendre transform to give a tractable method for studying Topological Data Analysis (TDA) in terms of sums of Gaussian kernels. In this paper, we prove a variant for sums of cosine similarity-based kernel…

Statistics Theory · Mathematics 2024-12-06 Erik Carlsson , Greg DePaul

Using renormalization group methods, we develop a rigorous coarse-grained representation of the dissipative dynamics of quantum excitations propagating inside open macromolecular systems. We show that, at very low spatial resolution, this…

Mesoscale and Nanoscale Physics · Physics 2014-04-23 E. Schneider , P. Faccioli

Transport properties of 2D materials especially close to their boundary has received much attention after the successful fabrication of graphene and other fascinating materials afterwards. While most previous work is devoted to the…

Mesoscale and Nanoscale Physics · Physics 2016-12-15 Fanbing Xia , Jian Wang

The two-time Green function method in quantum electrodynamics of high-Z few-electron atoms is described in detail. This method provides a simple procedure for deriving formulas for the energy shift of a single level and for the energies and…

Atomic Physics · Physics 2009-11-06 V. M. Shabaev

The structure-preserving doubling algorithm (SDA) is a fairly efficient method for solving problems closely related to Hamiltonian (or Hamiltonian-like) matrices, such as computing the required solutions to algebraic Riccati equations.…

Numerical Analysis · Mathematics 2020-05-19 Zhen-Chen Guo , Eric King-Wah Chu , Xin Liang , Wen-Wei Lin

The quantum transport through nanoscale junctions is governed by the charging energy $U$ of the device. We employ the recently developed scattering-states numerical renormalization group approach to open quantum systems to study…

Strongly Correlated Electrons · Physics 2010-04-12 Sebastian Schmitt , Frithjof B. Anders

We extend a previously proposed rotation and truncation scheme to optimize quantum Anderson impurity calculations with exact diagonalization [PRB 90, 085102 (2014)] to density-matrix renormalization group (DMRG) calculations. The method…

Strongly Correlated Electrons · Physics 2019-10-02 Y. Lu , X. Cao , P. Hansmann , M. W. Haverkort

Cellular Automata (CA) theory is a discrete model that represents the state of each of its cells from a finite set of possible values which evolve in time according to a pre-defined set of transition rules. CA have been applied to a number…

Computer Vision and Pattern Recognition · Computer Science 2017-05-22 Karttikeya Mangalam , K S Venkatesh

Quantum cascade lasers can be modeled within a hierarchy of different approaches: Standard rate equations for the electron densities in the levels, semiclassical Boltzmann equation for the microscopic distribution functions, and quantum…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 A. Wacker , S. -C. Lee , M. F. Pereira

We introduce a hybrid approach to applying the density matrix renormalization group (DMRG) to continuous systems, combining a grid approximation along one direction with a finite Gaussian basis set along the remaining two directions. This…

Chemical Physics · Physics 2017-08-02 E. Miles Stoudenmire , Steven R. White

Nanoscale electronic transport is of intense technological interest, with applications ranging from semiconducting devices and molecular junctions to charge migration in biological systems. Most explicit theoretical approaches treat…

Mesoscale and Nanoscale Physics · Physics 2014-08-08 Justin E. Elenewski , Hanning Chen

Decoherent transport in mesoscopic and nanoscopic systems can be formulated in terms of the D'Amato-Pastawski (DP) model. This generalizes the Landauer-B\"{u}ttiker picture by considering a distribution of local decoherent processes.…

Mesoscale and Nanoscale Physics · Physics 2014-05-02 Carlos J. Cattena , Lucas J. Fernández-Alcázar , Raúl A. Bustos-Marún , Daijiro Nozaki , Horacio M. Pastawski

Beyond the second-order Born approximation, we develop an improved master equation approach to quantum transport by virtue of a self-consistent Born approximation. The basic idea is replacing the free Green's function in the tunneling…

Mesoscale and Nanoscale Physics · Physics 2014-06-27 Jun Li , Jinshuang Jin , Xin-Qi Li , YiJing Yan

In the framework of the hybrid quantum-classical variational cluster approach (VCA) to strongly correlated electron systems one of the goals of a quantum subroutine is to find single-particle correlation functions of lattice fermions in…

Quantum Physics · Physics 2025-06-26 Gino Bishop , Dmitry Bagrets , Frank K. Wilhelm