scholarly journals Bounds on Mixed State Entanglement

Entropy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 62 ◽  
Author(s):  
Bruno Leggio ◽  
Anna Napoli ◽  
Hiromichi Nakazato ◽  
Antonino Messina
Keyword(s):  
Mixed State ◽  
General Framework ◽  
Quantum Correlations ◽  
Thermal Entanglement ◽  
Mixed States ◽  
Clear Explanation ◽  
Finite Dimensionality ◽  
Partial Transpose ◽  
The Subject

In the general framework of d 1 × d 2 mixed states, we derive an explicit bound for bipartite negative partial transpose (NPT) entanglement based on the mixedness characterization of the physical system. The derived result is very general, being based only on the assumption of finite dimensionality. In addition, it turns out to be of experimental interest since some purity-measuring protocols are known. Exploiting the bound in the particular case of thermal entanglement, a way to connect thermodynamic features to the monogamy of quantum correlations is suggested, and some recent results on the subject are given a physically clear explanation.

THERMAL DISCORD AND NEGATIVITY IN A TWO-SPIN-QUTRIT SYSTEM UNDER DIFFERENT MAGNETIC FIELDS

2013 ◽  
Vol 11 (08) ◽  
pp. 1350070 ◽  
Author(s):  
XIAO-JING LI ◽  
HUI-HUI JI ◽  
XI-WEN HOU
Keyword(s):  
Magnetic Fields ◽  
Quantum Discord ◽  
Strong Field ◽  
Quantum Correlations ◽  
Mixed States ◽  
Classical Correlation ◽  
Lower Temperature ◽  
Qubit States ◽  
Quantum And Classical Correlations

The characterization of quantum discord (QD) has been well understood only for two-qubit states and is little known for mixed states beyond qubits. In this work, thermal quantum discord is studied for a qutrit system in different magnetic fields, where classical correlation and entanglement negativity are calculated for comparison. It is shown that the discord is more robust against temperature than the negativity. For a suitable region of magnetic field and its direction, the discord is non-zero while the negativity is zero. When the system is at a lower temperature, these three quantities, however, display a similar behavior for the varied field and direction, and their discontinuities come from crossovers between different ground states in the system. Moreover, the inequality between the quantum and classical correlations depends upon the system parameters as well as the temperature. In particular, both correlations are equal at a suitable field, direction, and temperature. Remarkably, such an equality remains for a strong field in the antiparallel direction, while both correlations in two-qubit systems are identical for any antiparallel field and temperature. These are useful for quantum information and understanding quantum correlations in qutrit mixed states.

scholarly journals Characterization of Combinatorially Independent Permutation Separability Criteria

2005 ◽  
Vol 12 (04) ◽  
pp. 331-345 ◽  
Author(s):  
Paweł Wocjan ◽  
Michał Horodecki
Keyword(s):  
Density Matrix ◽  
The State ◽  
Necessary Condition ◽  
Trace Norm ◽  
Mixed States ◽  
Graphical Notation ◽  
Operational Conditions ◽  
Separability Criteria ◽  
Partial Transpose

The so-called permutation separability criteria are simple operational conditions that are necessary for separability of mixed states of multipartite systems: (1) permute the indices of the density matrix and (2) check if the trace norm of at least one of the resulting operators is greater than one. If it is greater than one then the state is necessarily entangled. A shortcoming of the permutation separability criteria is that many permutations give rise to equivalent separability criteria. Therefore, we introduce a necessary condition for two permutations to yield independent criteria called combinatorial independence. This condition basically means that the map corresponding to one permutation cannot be obtained by concatenating the map corresponding to the second permutation with a norm-preserving map. We characterize completely combinatorially independent criteria, and determine simple permutations that represent all independent criteria. The representatives can be visualized by means of a simple graphical notation. They are composed of three basic operations: partial transpose, and two types of so-called reshufflings. In particular, for a four-partite system all criteria except one are composed of partial transpose and only one type of reshuffling; the exceptional one requires the second type of reshuffling. Furthermore, we show how to obtain efficiently a simple representative for every permutation. This method allows to check easily if two permutations are combinatorially equivalent or not.

scholarly journals Informationally restricted correlations: a general framework for classical and quantum systems

Quantum ◽  
2022 ◽  
Vol 6 ◽  
pp. 620
Author(s):  
Armin Tavakoli ◽  
Emmanuel Zambrini Cruzeiro ◽  
Erik Woodhead ◽  
Stefano Pironio
Keyword(s):  
General Framework ◽  
Quantum Communication ◽  
Random Number ◽  
Quantum Correlations ◽  
Quantum Systems ◽  
Mixed States ◽  
Random Number Generators ◽  
New Methods ◽  
General Kind ◽  
Bell Nonlocality

We introduce new methods and tools to study and characterise classical and quantum correlations emerging from prepare-and-measure experiments with informationally restricted communication. We consider the most general kind of informationally restricted correlations, namely the ones formed when the sender is allowed to prepare statistical mixtures of mixed states, showing that contrary to what happens in Bell nonlocality, mixed states can outperform pure ones. We then leverage these tools to derive device-independent witnesses of the information content of quantum communication, witnesses for different quantum information resources, and demonstrate that these methods can be used to develop a new avenue for semi-device independent random number generators.

scholarly journals Reconstruction of Differential Operators with Frozen Argument

Axioms ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 24
Author(s):  
Oles Dobosevych ◽  
Rostyslav Hryniv
Keyword(s):  
Perturbation Theory ◽  
Spectral Properties ◽  
General Framework ◽  
Differential Operators ◽  
Inverse Spectral Problem ◽  
Complete Characterization ◽  
Rank One Perturbation ◽  
Clear Explanation ◽  
Rank One

We study spectral properties of a wide class of differential operators with frozen arguments by putting them into a general framework of rank-one perturbation theory. In particular, we give a complete characterization of possible eigenvalues for these operators and solve the inverse spectral problem of reconstructing the perturbation from the resulting spectrum. This approach provides a unified treatment of several recent studies and gives a clear explanation and interpretation of the obtained results.

THE USE OF VIDEO IN TEACHING LISTENING SKILL

2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Arjulayana -
Keyword(s):  
Learning Style ◽  
Teaching Process ◽  
Listening Skill ◽  
Clear Explanation ◽  
Visual Aid ◽  
Qualitative Descriptive ◽  
The Subject ◽  
Listening Process ◽  
Descriptive Method ◽  
Clear Information

ABSTRACT The objective of this research is to give understanding and clear explanation about teaching students’ listening skill by English video. Commonly, teaching listening through tape recorder, but in this research teacher shows different way, video is collaboration between pictures and sound components, and it contains a recording of a movie or television program. Students can be able to know the activity or a topic being discussion through visual aid and knowing the pictures expression clearly, this way can help students to get clear information both pronunciations and expression. Grade VIII of SMPN 15 Tangerang with total number is 20 students and 10 English teachersas the subject of the research.  Qualitative descriptive method is applied in this research to explain teaching process through video clearly, however, literature and questionnaere with close answer form is given to get the data. The result of this research are: firstly, teaching listening skill through video can be used by the teacher to make a listening class is more enjoyable and understandable, because audio visual aid can cover students various learning style, finally at the end of teaching and listening process the objectives of study can be gained. Secondly; teaching listening through video is very useful way to encourage and foster students’ listening skill and their interest.      Keywords: Using Video, Listening skill, teaching listening

The Image of the Accountant in a German Context

2004 ◽  
Vol 4 (1) ◽  
pp. 62-89 ◽  
Author(s):  
Andreas Hoffjan
Keyword(s):  
Content Analysis ◽  
Empirical Study ◽  
Cost Reduction ◽  
Maximum Degree ◽  
Work Ethic ◽  
Personal Characteristics ◽  
Management Accountant ◽  
The Subject ◽  
Professional Context

This study introduces content analysis as a method of examining the accountant's role. The empirical study is based on 73 advertisements, which are directed primarily at employees who are affected by the management accountant's work. The findings of the study indicate that the subject of accountancy is used particularly in connection with promises of “cost reduction.” Consequently, the majority of advertisements use the accountant stereotype of “savings personified.” In a professional context, the work ethic of the management accountant is given particular emphasis in the advertisements. He/she identifies him/herself with his/her task to the maximum degree, is regarded as loyal to his/her company and, for the most part, is well organized in his/her work. However, the characterization of the management accountant as a well disciplined company-person conflicts with the negative portrayal of his/her professional qualities. In advertisements, the management accountant is portrayed as a rather inflexible, passive, and uncreative specialist who, as a result of these qualities, often demotivates others. The personal characteristics of the management accountant are shown in a negative light. This gives him/her the unappealing image of a humorless, envious, dissociated, and ascetic corporate-person.

scholarly journals A Universal Model for the Log-Normal Distribution of Elasticity in Polymeric Gels and Its Relevance to Mechanical Signature of Biological Tissues

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Arnaud Millet
Keyword(s):  
Elastic Modulus ◽  
Normal Distribution ◽  
Biological Tissues ◽  
Force Microscopy ◽  
Polymeric Gels ◽  
Atomic Force ◽  
Clear Explanation ◽  
Log Normal ◽  
Log Normal Distribution

The mechanosensitivity of cells has recently been identified as a process that could greatly influence a cell’s fate. To understand the interaction between cells and their surrounding extracellular matrix, the characterization of the mechanical properties of natural polymeric gels is needed. Atomic force microscopy (AFM) is one of the leading tools used to characterize mechanically biological tissues. It appears that the elasticity (elastic modulus) values obtained by AFM presents a log-normal distribution. Despite its ubiquity, the log-normal distribution concerning the elastic modulus of biological tissues does not have a clear explanation. In this paper, we propose a physical mechanism based on the weak universality of critical exponents in the percolation process leading to gelation. Following this, we discuss the relevance of this model for mechanical signatures of biological tissues.

The treatment of mixed states and the risk of switching to depression

2005 ◽  
Vol 20 (2) ◽  
pp. 96-100 ◽  
Author(s):  
Eduard Vieta
Keyword(s):  
Clinical Trials ◽  
Depressive Symptoms ◽  
Mixed State ◽  
Atypical Antipsychotics ◽  
Randomized Clinical Trials ◽  
Mixed States ◽  
Conventional Antipsychotics

AbstractThere are few controlled studies evaluating the treatment of bipolar mixed states. Evidence suggests that mixed states may be more responsive to some anticonvulsants than to lithium. Olanzapine alone or in combination with divalproate or lithium has been adequately evaluated in randomized clinical trials involving mixed-state patients, whereas risperidone and quetiapine have not. There is also some evidence demonstrating the efficacy of ziprasidone and aripiprazole. The risk of switching to depression is high in mixed states. Conventional antipsychotics, such as haloperidol, may be less efficacious at protecting against a switch to depression than atypical antipsychotics, divalproate or lithium. When choosing drugs for the treatment of mania, and especially for the treatment of mixed states, their efficacy against manic and depressive symptoms, and their safety in terms of the risk of switching to depression should be taken into account.

scholarly journals Axiomatization and Measurement of Quasi-Hyperbolic Discounting *

2014 ◽  
Vol 129 (3) ◽  
pp. 1449-1499 ◽  
Author(s):  
José Luis Montiel Olea ◽  
Tomasz Strzalecki
Keyword(s):  
Hyperbolic Discounting ◽  
Partial Identification ◽  
Axiomatic Characterization ◽  
Discount Factors ◽  
Elasticity Of Intertemporal Substitution ◽  
Trade Offs ◽  
Subject Pool ◽  
Identification Approach ◽  
The Subject

Abstract This article provides an axiomatic characterization of quasi-hyperbolic discounting and a more general class of semi-hyperbolic preferences. We impose consistency restrictions directly on the intertemporal trade-offs by relying on what we call “annuity compensations.” Our axiomatization leads naturally to an experimental design that disentangles discounting from the elasticity of intertemporal substitution. In a pilot experiment we use the partial identification approach to estimate bounds for the distributions of discount factors in the subject pool. Consistent with previous studies, we find evidence for both present and future bias.

Characterization of stable processes by identically distributed stochastic integrals

1980 ◽  
Vol 12 (3) ◽  
pp. 689-709 ◽  
Author(s):  
M. Riedel
Keyword(s):  
Stochastic Process ◽  
Stable Process ◽  
Convergence In Probability ◽  
Stochastic Integrals ◽  
Stable Processes ◽  
Process With Independent Increments ◽  
Independent Increments ◽  
The Subject

Let X(t) be a homogeneous and continuous stochastic process with independent increments. The subject of this paper is to characterize the stable process by two identically distributed stochastic integrals formed by means of X(t) (in the sense of convergence in probability). The proof of the main results is based on a modern extension of the Phragmén-Lindelöf theory.

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