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The Kohn-Sham scheme of density functional theory is one of the most widely used methods to solve electronic structure problems for a vast variety of atomistic systems across different scientific fields. While the method is fast relative to…

A simple statistical model for the effects of dephasing on electron transport in one-dimensional quantum systems is introduced, which allows to adjust the degree of phase and momentum randomization independently. Hence, the model is able to…

Mesoscale and Nanoscale Physics · Physics 2012-07-30 Thomas Stegmann , Matías Zilly , Orsolya Ujsághy , Dietrich E. Wolf

An input-output model of a two-level quantum system in the Heisenberg picture is of bilinear form with constant system matrices, which allows the introduction of the concepts of controllability and observability in analogy with those of…

Quantum Physics · Physics 2019-09-18 Guofeng Zhang , Ian R. Petersen

In this article we derive a useful expectation identity using the language of quantum statistical mechanics, where density matrices represent the state of knowledge about the system. This identity allows to establish relations between…

Quantum Physics · Physics 2024-10-29 Boris Maulén , Sergio Davis , Daniel Pons

We introduce a local machine-learning method for predicting the electron densities of periodic systems. The framework is based on a numerical, atom-centred auxiliary basis, which enables an accurate expansion of the all-electron density in…

Chemical Physics · Physics 2021-11-10 Alan M. Lewis , Andrea Grisafi , Michele Ceriotti , Mariana Rossi

Parameterized tight-binding models fit to first principles calculations can provide an efficient and accurate quantum mechanical method for predicting properties of molecules and solids. However, well-tested parameter sets are generally…

Materials Science · Physics 2023-04-28 Kevin F. Garrity , Kamal Choudhary

The link of two concepts, indistinguishability and entanglement, with the energy-time uncertainty principle is demonstrated in a system composed of two strongly coupled bosonic modes. Working in the limit of a short interaction time, we…

Quantum Physics · Physics 2016-07-06 Smail Bougouffa , Zbigniew Ficek

We investigate a Kac-type many particle model that allows a reference-free description of plastic deformation. In the framework of the model a solid body is described by a set of particle positions. A lattice is fitted to the particle…

Mathematical Physics · Physics 2014-08-07 Stephan Luckhaus , Jens Wohlgemuth

The quantum average energy decay and the purity decay are studied for a system particle as a function of the number of constituents of a discrete bath model. The system particle is subjected to two distinct physical situations: the harmonic…

Quantum Physics · Physics 2011-11-02 M. D. Galiceanu , M. W. Beims , W. Strunz

Symmetry energy for asymmetric nuclear matter at subsaturation densitieswas investigated in the framework of an isospin-dependent quantum molecular dynamics model.Asingle ratio of neutrons and protons is comparedwith the experimental data…

Nuclear Theory · Physics 2011-11-18 Sanjeev Kumar , Y. G. Ma , G. Q. Zhang , C. L. Zhou

Descriptions of molecular systems usually refer to two distinct theoretical frameworks. On the one hand the quantum pure state, i.e. the wavefunction, of an isolated system which is determined to calculate molecular properties and to…

Statistical Mechanics · Physics 2011-03-17 Barbara Fresch , Giorgio J. Moro

The electronic structure of nanoscale moieties (such as molecules and quantum dots) governs the properties and performance of the bottom-up fabricated devices based on their assemblies. Accordingly, simple and faster experimental methods…

In two-dimensional noncommutive space for the case of both position - position and momentum - momentum noncommuting, a constraint between noncommutative parameters is investigated. The related topic of guaranteeing Bose - Einstein…

Quantum Physics · Physics 2007-05-23 Jian-Zu Zhang

We theoretically study the decoherence of a two-level quantum system coupled to noisy environments exhibiting linear and quadratic fluctuations within the framework of a stochastic Liouville equation. It is shown that the intrinsic energy…

Quantum Physics · Physics 2024-07-26 Xiangji Cai , Yanyan Feng , Jing Ren , Yonggang Peng , Yujun Zheng

We examine quantum normal typicality and ergodicity properties for quantum systems whose dynamics are generated by Hamiltonians which have residual degeneracy in their spectrum and resonance in their energy gaps. Such systems can be…

Quantum Physics · Physics 2016-01-06 Pouya Asadi , Faraj Bakhshinezhad , Ali T. Rezakhani

A brief review of the nanoscale free-electron model of metal nanowires is presented. This continuum description of metal nanostructures allows for a unified treatment of cohesive and conducting properties. Conductance channels act as…

Mesoscale and Nanoscale Physics · Physics 2010-06-22 D. F. Urban , J. Bürki , C. A. Stafford , Hermann Grabert

Using methods borrowed from machine learning we detect in a fully algorithmic way long range effects on local physical properties in a simple covalent system of carbon atoms. The fact that these long range effects exist for many…

Materials Science · Physics 2020-09-18 Behnam Parsaeifard , Jonas A. Finkler , Stefan Goedecker

Physical property of a single quantum object is governed by its precise atomic arrangement. The direct correlation of localized physical properties with the atomic structures has been therefore strongly desired but still limited in the…

Atomic Physics · Physics 2021-01-29 Ryosuke Senga , Thomas Pichler , Kazu Suenaga

We show that a newly proposed Shannon-like entropic measure of shape complexity applicable to spatially-localized or periodic mathematical functions known as configurational entropy (CE) can be used as a predictor of spontaneous decay rates…

Atomic Physics · Physics 2018-03-26 Marcelo Gleiser , Nan Jiang

An outstanding challenge in chemical computation is the many-electron problem where computational methodologies scale prohibitively with system size. The energy of any molecule can be expressed as a weighted sum of the energies of…

Chemical Physics · Physics 2023-01-03 LeeAnn M. Sager-Smith , David A. Mazziotti