REVIEW ON SYSTEM-SPIN ENVIRONMENT DYNAMICS OF QUANTUM DISCORD

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345055 ◽  
Author(s):  
BEN-QIONG LIU ◽  
BIN SHAO ◽  
JUN-GANG LI ◽  
JIAN ZOU
Keyword(s):  
Quantum Discord ◽  
Open Systems ◽  
Quantum Phase Transitions ◽  
Physical Models ◽  
Quantum Computers ◽  
Bipartite State ◽  
External Perturbations ◽  
Mathematical Properties ◽  
Spin Pairs ◽  
The Relationship

Recent work has relatively comprehensively studied the quantum discord, which is supposed to account for all the nonclassical correlations present in a bipartite state (including entanglement), and provide computational speedup and quantum enhancement even in separable states. Firstly, we introduce several different indicators of nonclassical correlations, including their definitions and interpretations, mathematical properties, and the relationship between them. Secondly, we review two major topics of quantum discord. One is the remarkable behavior at quantum phase transitions. The pairwise quantum discord for nearest neighbors as well as distant spin pairs can perfectly signal the critical behavior of many physical models, even at finite temperatures. The other is quantum discord dynamics in open systems, especially for "system-spin environment" models. Quantum discord is more robust than entanglement against external perturbations. It can be created, greatly amplified or protected under certain conditions, and presents promising applications in quantum technologies such as quantum computers.

NON-MARKOVIAN OPEN QUANTUM SYSTEMS: SYSTEM–ENVIRONMENT CORRELATIONS IN DYNAMICAL MAPS

2011 ◽  
Vol 09 (07n08) ◽  
pp. 1617-1634 ◽  
Author(s):  
CÉSAR A. RODRÍGUEZ-ROSARIO ◽  
E. C. G. SUDARSHAN
Keyword(s):  
Master Equation ◽  
Quantum Discord ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Complete Positivity ◽  
System Environment ◽  
Open Quantum ◽  
Mathematical Properties ◽  
Classical Correlations ◽  
The Relationship

We construct a non-Markovian dynamical map that accounts for systems correlated to the environment. We refer to it as a canonical dynamical map, which forms an evolution family. The relationship between inverse maps and correlations with the environment is established. The mathematical properties of complete positivity is related to classical correlations, according to quantum discord, between the system and the environment. A generalized non-Markovian master equation is derived from the canonical dynamical map.

Quantum Discord of Two Bosonic Modes in Two-Reservoir Model

2013 ◽  
Vol 20 (03) ◽  
pp. 1340003 ◽  
Author(s):  
Aurelian Isar
Keyword(s):  
Quantum Discord ◽  
Open Systems ◽  
Vacuum State ◽  
Quantum Correlations ◽  
Continuous Variable ◽  
Reservoir Model ◽  
Bipartite State ◽  
Thermal Environments ◽  
Gaussian Input ◽  
Gaussian Quantum Discord

In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous variable quantum discord for a system consisting of two non-interacting bosonic modes embedded in two independent thermal environments. We describe the evolution of discord in terms of the covariance matrix for Gaussian input states. In the case of an entangled initial squeezed vacuum state, we analyze the time evolution of the Gaussian quantum discord, which is a measure of all quantum correlations in the bipartite state, including entanglement, and show that quantum discord decays asymptotically in time under the effect of the thermal reservoirs. For an initial separable pure state, the Gaussian quantum discord is zero and it keeps this value during the whole evolution of the system.

Identifying Physico-Chemical Laws from the Robotically Collected Data

2019 ◽  
Author(s):  
Liwei Cao ◽  
Danilo Russo ◽  
Vassilios S. Vassiliadis ◽  
Alexei Lapkin
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Predictor Variable ◽  
Physical Models ◽  
Training Data ◽  
Mixed Integer ◽  
Physico Chemical ◽  
Data Points ◽  
Future Work ◽  
The Relationship

<p>A mixed-integer nonlinear programming (MINLP) formulation for symbolic regression was proposed to identify physical models from noisy experimental data. The formulation was tested using numerical models and was found to be more efficient than the previous literature example with respect to the number of predictor variables and training data points. The globally optimal search was extended to identify physical models and to cope with noise in the experimental data predictor variable. The methodology was coupled with the collection of experimental data in an automated fashion, and was proven to be successful in identifying the correct physical models describing the relationship between the shear stress and shear rate for both Newtonian and non-Newtonian fluids, and simple kinetic laws of reactions. Future work will focus on addressing the limitations of the formulation presented in this work, by extending it to be able to address larger complex physical models.</p><p><br></p>

Sources of morphological variation and organization within and among populations of Balsamorhiza sagittata

1988 ◽  
Vol 66 (1) ◽  
pp. 11-17 ◽  
Author(s):  
K. A. Robson ◽  
R. K. Scagel ◽  
J. Maze
Keyword(s):  
Open Systems ◽  
Second Law Of Thermodynamics ◽  
Population Diversity ◽  
Individual Plant ◽  
Theory Of Evolution ◽  
Plant Parts ◽  
The Individual ◽  
The Relationship ◽  
Balsamorhiza Sagittata ◽  
Two Populations

Comparisons of differences between morphological means of individual plant parts indicate that the greatest source of variation in two populations of Balsamorhiza sagittata is the individual plants within populations; within-population diversity is greater than among-population diversity. Variable covariance and correlations differ between individual plants and there are subgroups of interrelated variables that can be tied to developmental phenomena. The relationship between developmental phenomena and these groups of variables suggests a relationship between organizational, as reflected in variable interrelationships, and ontogenetic variation. These results are not adequately explained by neoDarwinian theory but are explained more comprehensively by a theory of evolution that views biological change over time as an intrinsically driven self-organization, accompanied by an increase in complexity (a manifestation of the "Second Law of Thermodynamics" as it applies to open systems).

scholarly journals GENETIC VARIABILITY MAINTAINED BY MUTATION AND OVERDOMINANT SELECTION IN FINITE POPULATIONS

Genetics ◽  
1981 ◽  
Vol 98 (2) ◽  
pp. 441-459 ◽  
Author(s):  
Takeo Maruyama ◽  
Masatoshi Nei
Keyword(s):  
Mutation Rate ◽  
Allozyme Polymorphism ◽  
Random Genetic Drift ◽  
Effective Population ◽  
Mathematical Properties ◽  
Overdominant Selection ◽  
Mean And Variance ◽  
The Mean ◽  
Neutral Mutations ◽  
The Relationship

ABSTRACT Mathematical properties of the overdominance model with mutation and random genetic drift are studied by using the method of stochastic differential equations (Itô and McKean 1974). It is shown that overdominant selection is very powerful in increasing the mean heterozygosity as compared with neutral mutations, and if 2Ns (N = effective population size; s = selective disadvantage for homozygotes) is larger than 10, a very low mutation rate is sufficient to explain the observed level of allozyme polymorphism. The distribution of heterozygosity for overdominant genes is considerably different from that of neutral mutations, and if the ratio of selection coefficient (s) to mutation rate (ν) is large and the mean heterozygosity (h) is lower than 0.2, single-locus heterozygosity is either approximately 0 or 0.5. If h increases further, however, heterozygosity shows a multiple-peak distribution. Reflecting this type of distribution, the relationship between the mean and variance of heterozygosity is considerably different from that for neutral genes. When s/v is large, the proportion of polymorphic loci increases approximately linearly with mean heterozygosity. The distribution of allele frequencies is also drastically different from that of neutral genes, and generally shows a peak at the intermediate gene frequency. Implications of these results on the maintenance of allozyme polymorphism are discussed.

scholarly journals Socioecological resilience of typical citrus fruit agroecosystems

2019 ◽  
Vol 13 (2) ◽  
pp. 186-199
Author(s):  
José Alejandro Cleves-Leguizamo ◽  
Hernan Salamanca-Sanjuanes ◽  
Liven Fernando Martínez-Bernal
Keyword(s):  
Land Tenure ◽  
Open Systems ◽  
Statistical Significance ◽  
Citrus Fruit ◽  
Chi Square ◽  
Cultural Variables ◽  
Cultural Conditions ◽  
The Difference ◽  
Social Organizational ◽  
The Relationship

This paper, as a tool for analysis, considered the capacity of the interaction that open systems have against the occurrence of disturbances so that they can continue to function with minimal losses of energy, called resilience, an emerging characteristic of agroecosystems. To establish a method to measure this characteristic, ten variables were evaluated, including seven cultural variables: level of schooling, land tenure type, saving capacity, social organizational identity, farm infrastructure, weed control and production system; and three ecosystem variables: water resource availability, phytosanitary management and Main Agroecological Structure (MAS) in typical citrus fruit agroecosystems. These were methodologically grouped into six recommended domains: groups of farms and citrus growers with similar ecosystem and cultural conditions that have been characterized and typified in a previous study. In each of these groups, three farm types were selected for a total of 18 production units (department of Meta, Colombia). To determine the difference between the variables, Chi-square tests were applied (using the Pearson and Fisher statistics). Network analysis was applied to determine the relationship between the variables. The resilience was not significantly correlated with level of schooling, farm infrastructure or MAS. The relationship between the resilience and cultural variables presented a high significance, whereas the ecosystem variables showed a low statistical significance.

Signals from the Goal

Runaway ◽  
2017 ◽  
Author(s):  
Anthony Chaney
Keyword(s):  
Negative Feedback ◽  
Positive Feedback ◽  
Scientific Inquiry ◽  
Outer Space ◽  
Physical Models ◽  
A Value ◽  
William Bateson ◽  
Theories Of Evolution ◽  
The Relationship

This chapter places Bateson's work with dolphins within a broader 1960s "dolphin mystique"--a cultural site where anxieties over modern science’s physical models went unresolved. Most associated with scientist John C. Lilly, the dolphin mystique had futurist, utilitarian, and romantic components, also found in a similar "outer space mystique." The chapter shows how Lilly's and Bateson's research goals differed through a further substantiation of the sources of Bateson's thought: the Macy Conferences on Cybernetics (his theory of play, the concepts of positive feedback, negative feedback, servomechanisms, and the naturalization of teleology); and his father William Bateson and his career amid the ongoing conflict between Darwinist and Lamarckian theories of evolution. In Hawaii, Bateson expressed his isolation from potential peers and research frustrations in letters to old friend and Darwin granddaughter/scholar Nora Barlow. This isolation, however, allowed Bateson to articulate a justification for scientific inquiry that was neither utilitarian nor a value-neutral pursuit of truth, but an effort to establish an accurate depiction of the relationship between nature and the human self, which he called the riddle of the Sphinx.

scholarly journals INTERPLAY BETWEEN QUANTUM PHASE TRANSITIONS AND THE BEHAVIOR OF QUANTUM CORRELATIONS AT FINITE TEMPERATURES

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345032 ◽  
Author(s):  
T. WERLANG ◽  
G. A. P. RIBEIRO ◽  
GUSTAVO RIGOLIN
Keyword(s):  
Phase Transitions ◽  
Critical Point ◽  
Thermodynamic Limit ◽  
Quantum Discord ◽  
Quantum Phase Transitions ◽  
Quantum Correlations ◽  
Infinite Chain ◽  
Quantum Phase ◽  
Absolute Zero ◽  
Zero Temperature

We review the main results and ideas showing that quantum correlations at finite temperatures (T), in particular quantum discord, are useful tools in characterizing quantum phase transitions (QPT) that only occur, in principle, at the unattainable absolute zero temperature. We first review some interesting results about the behavior of thermal quantum discord for small spin-1/2 chains and show that they already give us important hints of the infinite chain behavior. We then study in detail and in the thermodynamic limit (infinite chains) the thermal quantum correlations for the XXZ and XY models, where one can clearly appreciate that the behavior of thermal quantum discord at finite T is a useful tool to spotlight the critical point of a QPT.

PATTERNS AND PROCESSES IN MORPHOSPACE: GEOMETRIC MORPHOMETRICS OF THREE-DIMENSIONAL OBJECTS

2016 ◽  
Vol 22 ◽  
pp. 71-99 ◽  
Author(s):  
P. David Polly ◽  
Gary J. Motz
Keyword(s):  
Geometric Morphometrics ◽  
Three Dimensional ◽  
Shape Space ◽  
Multivariate Methods ◽  
Morphometric Data ◽  
Three Dimensional Objects ◽  
Mathematical Properties ◽  
Patterns And Processes ◽  
The Relationship ◽  
Shell Coiling

AbstractFocusing on geometric morphometrics (GMM), we review methods for acquiring morphometric data from 3-D objects (including fossils), algorithms for producing shape variables and morphospaces, the mathematical properties of shape space, especially how they relate to morphogenetic and evolutionary factors, and issues posed by working with fossil objects. We use the Raupian shell-coiling equations to illustrate the complexity of the relationship between such factors and GMM morphospaces. The complexity of these issues re-emphasize what are arguably the two most important recommendations for GMM studies: 1) always use multivariate methods and all of the morphospace axes in an analysis; and 2) always anticipate the possibility that the factors of interest can have complex, nonlinear relationships with shape.

Measurement of quantum correlation by Frobenius norm in non-Markovian system

2018 ◽  
Vol 16 (03) ◽  
pp. 1850022 ◽  
Author(s):  
Juju Hu ◽  
Shuqin Liu ◽  
Yinghua Ji
Keyword(s):  
Density Matrix ◽  
Quantum System ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Frobenius Norm ◽  
Easy Method ◽  
Test Matrix ◽  
Research Results ◽  
Bipartite State ◽  
Markovian System

In order to measure the quantum correlation of a bipartite state quickly, an easy method is to construct a test matrix through the commutations among the blocks of its density matrix. Then, the Frobenius norm of the test matrix can be used to measure the quantum correlation. In this paper, we apply the measurement by Frobenius norm ([Formula: see text] to the dynamics evolution of the non-Markovian quantum system and compare it with the typical quantum discord ([Formula: see text] proposed by Ollivier and Zurek. The research results show that [Formula: see text] can indeed measure the quantum correlation of a bipartite state as same as [Formula: see text]. Further studies find that there are still differences between the two measurements: in some regions, when [Formula: see text] is zero, [Formula: see text] is not zero. It indicates that [Formula: see text] is more detailed than [Formula: see text] to measure quantum correlation of a bipartite state.

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