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We investigate fully self-consistent multiscale quantum-classical algorithms on current generation superconducting quantum computers, in a unified approach to tackle the correlated electronic structure of large systems in both quantum…

Density estimation is a central task in statistics and machine learning. This problem aims to determine the underlying probability density function that best aligns with an observed data set. Some of its applications include statistical…

In a paper of us, it is showed that Density Matrices do not provide a complete description of ensembles of states in quantum mechanics, since they lack measurable information concerning the preparation of the ensembles. Bodor and Di\'osi…

Quantum Physics · Physics 2012-04-06 F. Fratini , A. G. Hayrapetyan

Quantum density matrix represents all the information of the entire quantum system, and novel models of meaning employing density matrices naturally model linguistic phenomena such as hyponymy and linguistic ambiguity, among others in…

Computation and Language · Computer Science 2024-03-14 X. Q. Zhao , T. L. Chen

While in relativity theory space evolves over time into a single entity known as spacetime, quantum theory lacks a standard notion of how to encapsulate the dynamical evolution of a quantum state into a single "state over time". Recently it…

Quantum Physics · Physics 2025-04-30 James Fullwood

We define the model of quantum circuits with density matrices, where non-unitary gates are allowed. Measurements in the middle of the computation, noise and decoherence are implemented in a natural way in this model, which is shown to be…

Quantum Physics · Physics 2007-05-23 Dorit Aharonov , Alexei Kitaev , Noam Nisan

With the decline of the Copenhagen interpretation of quantum mechanics and the recent experiments indicating that quantum mechanics does actually embody 'objective reality', one might ask if a 'mechanical', conceptual model for quantum…

Quantum Physics · Physics 2014-06-23 Carl Frederick

We provide a simple analytic relation which connects the density operator of the radiation field with the number probabilities. The problem of experimentally "sampling" a general matrix elements is studied, and the deleterious effects of…

Quantum Physics · Physics 2010-12-17 Stefano Mancini , Paolo Tombesi , Vladimir I. Manko

There is a newly emerging understanding that in the chaotic domain of isolated finite interacting many particle systems smoothed densities define the statistical description of these systems and these densities follow from embedded…

Chaotic Dynamics · Physics 2007-05-23 V. K. B. Kota , R. Sahu

Word meaning has different aspects, while the existing word representation "compresses" these aspects into a single vector, and it needs further analysis to recover the information in different dimensions. Inspired by quantum probability,…

Computation and Language · Computer Science 2020-04-09 Shen Li , Renfen Hu , Jinshan Wu

Embedded random matrix ensembles are generic models for describing statistical properties of finite isolated interacting quantum many-particle systems. For the simplest spinless systems, with say $m$ particles in $N$ single particle states…

Quantum Physics · Physics 2015-04-06 V. K. B. Kota , Manan Vyas

In some cases the state of a quantum system with a large number of subsystems can be approximated efficiently by the density matrix renormalization group, which makes use of redundancies in the description of the state. Here we show that…

Strongly Correlated Electrons · Physics 2009-02-03 Michael J. Hartmann , Javier Prior , Stephen R. Clark , Martin B. Plenio

We introduce with geometric means a density matrix decomposition of a multipartite quantum system of a finite dimension into two density matrices: a separable one, also known as the best separable approximation, and an essentially entangled…

Quantum Physics · Physics 2015-10-28 V. M. Akulin , G. A. Kabatyanski , A. Mandilara

By using of a special reduction way of density matrices, in this Letter we find the entanglement between two bunches of particles, its measure can be represented by the entanglement of formation.

Quantum Physics · Physics 2007-05-23 Zai-Zhe Zhong

A basic linearity of quantum dynamics, that density matrices are mapped linearly to density matrices, is proved very simply for a system that does not interact with anything else. It is assumed that at each time the physical quantities and…

Quantum Physics · Physics 2009-11-11 Thomas F. Jordan

We derive a density matrix (DM) theory for quantum cascade lasers (QCLs) that describes the influence of scattering on coherences through a generalized scattering superoperator. The theory enables quantitative modeling of QCLs, including…

Mesoscale and Nanoscale Physics · Physics 2017-08-28 Andrew Pan , Benjamin A. Burnett , Chi On Chui , Benjamin S. Williams

Various topics concerning the entanglement of composite quantum systems are considered with particular emphasis concerning the strict relations of such a problem with the one of attributing objective properties to the constituents. Most of…

Quantum Physics · Physics 2007-05-23 Giancarlo Ghirardi , Luca Marinatto , Tullio Weber

The rapid development of quantum computers has enabled demonstrations of quantum advantages on various tasks. However, real quantum systems are always dissipative due to their inevitable interaction with the environment, and the resulting…

Properties that are necessarily formulated within pure (symmetric) expectation values are difficult to calculate for projector quantum Monte Carlo approaches, but are critical in order to compute many of the important observable properties…

Computational Physics · Physics 2015-06-23 Catherine Overy , George H. Booth , N. S. Blunt , James Shepherd , Deidre Cleland , Ali Alavi

Subsystems of composite quantum systems are described by reduced density matrices, or quantum marginals. Important physical properties often do not depend on the whole wave function but rather only on the marginals. Not every collection of…

Quantum Physics · Physics 2014-10-31 Michael Walter