Quantum discord and its dynamics for multipartite systems

Quantum discord, one of the famous quantum correlations, has been recently generalized to multipartite systems by Radhakrishnan et al. Here we give analytical solutions of the quantum discord for a family of N-qubit quantum states. For the bipartite system, we derive a zero quantum discord which will remain unchanged under the phase damping channel. For multiparitite systems, it is found that the quantum discord can be classified into three categories and the quantum discord for odd-partite systems can exhibit freezing under the phase damping channel, while the freezing does not exist in the even-partite systems.

Phylotranscriptomic discordance is best explained by incomplete lineage sorting within Allium subgenus Cyathophora and thus hemiplasy accounts for interspecific trait transition

The transition of traits between genetically related lineages is a fascinating topic that provides clues to understanding the drivers of speciation and diversification.Much can be learned about this process from phylogeny-based trait evolution.However,such inference is often plagued by genome-wide gene-tree discordance(GTD),mostly due to incomplete lineage sorting(ILS)and/or introgressive hybridization,especially when the genes underlying the traits appear discordant.Here,by collecting transcriptomes,whole chloroplast genomes(cpDNA),and population genetic datasets,we used the coalescent model to turn GTD into a source of information for ILS and employed hemiplasy to explain specific cases of apparent“phylogenetic discordance”between different morphological traits and probable species phylogeny in the Allium subg.Cyathophora.Both concatenation and coalescence methods consistently showed the same phylogenetic topology for species tree inference based on single-copy genes(SCGs),as supported by the KS distribution.However,GTD was high across the genomes of subg.Cyathophora:~27%e38.9%of the SCG trees were in conflict with the species tree.Plasmid and nuclear incongruence was also present.Our coalescent simulations indicated that such GTD was mainly a product of ILS.Our hemiplasy risk factor calculations supported that random fixation of ancient polymorphisms in different populations during successive speciation events along the subg.Cyathophora phylogeny may have caused the character transition,as well as the anomalous cpDNA tree.Our study exemplifies how phylogenetic noise can be transformed into evolutionary information for understanding character state transitions along species phylogenies.

Retrospective analysis of discordant results between histology and other clinical diagnostic tests on helicobacter pylori infection

BACKGROUND A reliable test is essential for diagnosing Helicobacter pylori(H.pylori)infection,and crucial for managing H.pylori-related diseases.Serving as an excellent method for detecting H.pylori infection,histologic examination is a test that clinicians heavily rely on,especially when complemented with immunohistochemistry(IHC).Additionally,other diagnostic tests for H.pylori,such as the rapid urease test(CLO test)and stool antigen test(SA),are also highly sensitive and specific.Typically,the results of histology and other tests align with each other.However,on rare occasions,discrepancy between histopathology and other H.pylori diagnostic tests occurs.AIM To investigate the discordance between histology and other H.pylori tests,the underlying causes,and the impact on clinical management.METHODS Pathology reports of gastric biopsies were retrieved spanning August 2013 and July 2018.Reports were included in the study only if there were other H.pylori tests within seven days of the biopsy.These additional tests include CLO test,SA,and H.pylori culture.Concordance between histopathology and other tests was determined based on the consistency of results.In instances where histology results were negative while other tests were positive,the slides were retrieved for re-assessment,and the clinical chart was reviewed.RESULTS Of 1396 pathology reports were identified,each accompanied by one additional H.pylori test.The concordance rates in detecting H.pylori infection between biopsy and other tests did not exhibit significant differences based on the number of biopsy fragments.117 discrepant cases were identified.Only 20 cases(9 with CLO test and 11 with SA)had negative biopsy but positive results in other tests.Four cases initially stained with Warthin-Starry turned out to be positive for H.pylori with subsequent IHC staining.Among the remaining 16 true discrepant cases,10 patients were on proton pump inhibitors before the biopsy and/or other tests.Most patients underwent treatment,except for two who were untreated,and two patients who were lost to follow-up.CONCLUSION There are rare discrepant cases with negative biopsy but positive in SA or CLO test.Various factors may contribute to this inconsistency.Most patients in such cases had undergone treatment.

Egg recognition and nestling discrimination in the Crested Myna(Acridotheres cristatellus):Size matters

Most studies exploring abilities of hosts to detect brood parasitism are based on detecting colour and/or pattern differences among parasitic and host eggs or nestlings,while only few were focused on size differences.True recognition and recognition by discordancy are used to explain cognitive mechanisms of host egg recognition;however,only a few studies have found that hosts use recognition by discordancy.This study investigated:1)whether egg and nestling recognitions in the Crested Myna(Acridotheres cristatellus) are based on size cues;2)whether the egg cognitive mechanism is recognition by discordancy based on size cues;and 3) whether the longer the experiment time,the higher the egg recognition rate.Our results showed that the Crested Myna uses egg or nestling size as a recognition cue while the egg and nestling colour and patterning are not associated with egg or nestling rejection,thus the cognitive mechanism of egg recognition in the Crested Myna is recognition by discordancy based on egg size cues.Furthermore,there is a rejection delay in time of egg rejection behaviour of the Crested Myna.Therefore,we suggest that the periodicity of egg rejection experiments could be appropriately extended,especially for species with relatively low egg recognition ability.

Geometric discord of tripartite quantum systems

We study the quantification of geometric discord for tripartite quantum systems.Firstly,we obtain the analytic formula of geometric discord for tripartite pure states.It is already known that the geometric discord of pure states reduces to the geometric entanglement in bipartite systems,the results presented here show that this property is no longer true in tripartite systems.Furthermore,we provide an operational meaning for tripartite geometric discord by linking it to quantum state discrimination,that is,we prove that the geometric discord of tripartite states is equal to the minimum error probability to discriminate a set of quantum states with von Neumann measurement.Lastly,we calculate the geometric discord of three-qubit Bell diagonal states and then investigate the dynamic behavior of tripartite geometric discord under local decoherence.It is interesting that the frozen phenomenon exists for geometric discord in this scenario.

A wide hybrid zone mediated by precipitation contributed to confused geographical structure of Scutiger boulengeri

Confused geographical structure of a population and mitonuclear discordance are shaped by a combination of rapid changes in population demographics and shifts in ecology.In this study,we generated a time-calibrated phylogeny of Scutiger boulengeri,an endemic Xizang alpine toad occurring in mountain streams on the Qinghai-Xizang(Tibet)Plateau(QTP).Based on three mitochondrial DNA(mt DNA)genes,eight clades were assigned to three deeply divergent lineages.Analysis of nuclear DNA(nu DNA)genes revealed three distinct clusters without geographic structure,indicating significantly high rates of gene flow.Coalescent theory framework analysis(approximate Bayesian computation model DIYABC and Migrate-N)suggested that divergence of the main intraspecific clusters was the result of hybridization after secondary contact in the Holocene around 0.59 million years ago(Ma).The ratio of mt DNA FST(fixation index)to nu DNA FST was 2.3,thus failing to show male-biased dispersal.Geographic cline analysis showed that a wide hybrid zone was initially established in southwestern China,without significant reproductive isolation but with strong introgression in S.boulengeri,suggesting high hybrid fitness.Furthermore,mt DNA genes exhibited isolation by distance(IBD)while nu DNA genes exhibited significant isolation by environment(IBE).Results suggested that mitonuclear discordance may have initially been caused by geographic isolation,followed by precipitation-mediated hybridization,producing a wide hybrid zone and geographic structure confusion of nu DNA genes in S.boulengeri.This study indicated that complicated historical processes may have led to specific genetic patterns,with a specific climate factor facilitating gene flow in the system.

Discrepancy among microsatellite instability detection methodologies in non-colorectal cancer:Report of 3 cases

BACKGROUND Microsatellite instability(MSI)is a predictive biomarker for cancer immunotherapy.The tumor-agnostic nature of MSI makes it a denominator for immunotherapy in several solid tumors.It can be assessed using next-generation sequencing(NGS),fluorescent multiplex PCR,and immunohistochemistry(IHC).CASE SUMMARY Here,we report 3 cases with discordant MSI results detected using different methods.A cholangiocellular carcinoma case revealed proficient mismatch repair(MMR)by IHC but high MSI(MSI-H)by liquid NGS.A cervical cancer case revealed deficient MMR by IHC,microsatellite stable by PCR,and MSI-H by NGS.Lastly,an endometrial cancer case revealed proficient MMR by IHC but MSI-H by NGS.CONCLUSION IHC for MMR status is the first choice due to several advantages.However,in cases of indeterminate IHC results,molecular testing by MSI-PCR is preferred.Recently,NGS-based MSI assays are being widely used to detect MSI-H tumors.All three methods have high accuracy;however,the inconsistencies between them may lead to misdiagnosis.

Profile of Discordant Couples for Human Immunodeficiency Virus Infection Followed in Kinshasa: Case of Monkole Medical Center

Background: Programs targeting serodiscordant couples in Africa are not a priority in efforts to prevent Human Immunodeficiency Virus (HIV) infection, although a large proportion of these occur in stable relationships, of which serodiscordance accounts for about two-thirds with a high risk of seroconversion of the seronegative partner. Objective: The objective of this study was to describe the profile of HIV serodiscordant couples followed in Kinshasa, DRC. Methods: Descriptive cross-sectional study to describe the profile of different heterosexual HIV serodiscordant couples followed at the Monkole Medical Center in Kinshasa, DRC, from November 2021 to June 2022. The data were collected from the information sheets elaborated by the research team as well as from the information provided by the computerized files of the patients managed at the Infectious Diseases Unit of the Monkole Medical Center after the signature of the informed consent. An average of 8 cc of blood was taken from a peripheral vein in the patient’s forearm, and was stored in EDTA tubes at −20˚C, of which at least 6 mL were used for biochemical analyses, 2 spots of 200 μL for each partner were stored on filter paper at −20˚C and were used for DNA extraction. Nested PCR confirmed the serological diagnosis. Results: Out of a total of 482 heterosexual couples followed for HIV at the Monkole Medical Center, 28 (5.8%) were HIV serodiscordant, of which 14 (2.9%) couples agreed to participate in the present study. The mean age was 43.39 ± 10 years with extremes ranging from 24 to 62 years. The patients were mainly from the informal sector (53.6%) and weighed between 61 and 71 kg (46.4%). Sexual intercourse continued in all couples, without condom use (85.7%) for desire of procreation (82.1%);although the great majority of HIV-negative partners (85.7%) were not under ARV prophylaxis. Leukopenia was found in 42.9% of HIV-negative partners compared to 21% of HIV-positive partners;all partners had a predominantly lymphocytic white blood cell count. 21.4% of HIV-negative partners had high HDL, 14.3% of HIV-positive partners had low HDL, and 14.3% of HIV-negative partners had high LDL. Chi-square and Pearson correlation tests showed no relationship between the biochemical parameters performed and the couples’ serodiscordance for HIV. Conclusion: The frequency of HIV discordant couples in Kinshasa is significant. Serodiscordance is encountered in young intellectual and entrepreneurial couples with a desire to procreate. It is desirable to carry out further analyses for better management of these couples.

Egg rejection and egg recognition mechanisms in Oriental Reed Warblers

Background:Nest parasitism by cuckoos(Cuculus spp.)results in enormous reproductive failure and forces hosts to evolve antiparasitic strategies,i.e.,recognition of own eggs and rejection of cuckoo eggs.There are often sexual conflicts between male and female individuals in the expression of antiparasitic behavior due to the differences in reproductive inputs and division of labor.Methods:By adding a foreign egg made of blue soft clay to the host nest during early incubation period in the field,and by removing several host eggs and adding experimental eggs to control the proportion of two egg types in the nest,we examined egg rejection ability,egg recognition mechanism and sexual difference in egg rejection of the Oriental Reed Warbler(Acrocephalus orientalis),one of the major hosts of Common Cuckoos(Cuculus canorus).Results:Our results indicated that Oriental Reed Warblers can recognize and reject nearly 100%(73/75)of the nonmimetic eggs made of blue soft clay,and they could reject foreign eggs with 100%accuracy,regardless of the ratio of experimental eggs and its own eggs in the nest.Furthermore,all cases of egg rejections recorded by videos were only carried out by females.Conclusions:Oriental Reed Warblers have a high egg recognition ability and show a true recognition mechanism.Only female warblers perform egg rejection,suggesting that the sex for host egg incubation seems to play an important role in the evolution of egg recognition mechanisms.

外磁场下两量子比特海森堡XXZ模型中量子关联和热纠缠的研究

通过在两量子位上分别施加独立可控的外磁场(B+b)和(B-b),以及改变耦合参数J_z、磁场强度B、磁场不均匀度b和系统的温度kT,探讨了两量子比特XXZ模型中量子关联的变化行为,并在相同参数下与热纠缠做了比较。结果表明:量子关联存在的参数范围比热纠缠更广;而且在一定的参数范围内,量子关联和热纠缠的变化展示出不同的行为。

量子Discord简介及其在特定系统中的计算

量子Discord作为一种比量子纠缠更准确地刻画系统量子关联的物理量,在量子信息理论中备受关注.本文首先简略介绍量子Discord的基本概念,然后以横场Ising系统为例,讨论了量子Discord的一种计算方法.最后根据横场Ising系统的量子Discord得到了表征其特征的三维图像,并讨论了系统中两格点间的关联特性.

压缩真空态中原子与场的量子纠缠和量子discord

在压缩真空库中,研究了原子与场的相互作用下二比特体系的量子discord和量子纠缠的动力学行为.重点分析了原子的初始态系数和压缩真空库的压缩系数对量子纠缠和量子discord的影响.通过数值分析我们得到,随着原子的初始态系数和压缩真空库的压缩系数值的增加,量子纠缠和量子discord都会减小,但量子纠缠比量子discord减小的更快一些.最后研究了在原子的初始态系数和压缩真空库的压缩系数的值相同的情况下,量子discord比量子纠缠存在的时间更长些.

Influence of bed elevation discordance on flow patterns and head losses in an open-channel confluence

Confluences play a major role in the dynamics of networks of natural and man-made open channels, and field measurements on river confluences reveal that discordance in bed elevation is common.Studies of schematized confluences with a step at the interface between the tributary and the main channel bed reveal that bed elevation discordance is an important additional control for the confluence hydrodynamics.This study aimed to improve understanding of the influence of bed elevation discordance on the flow patterns and head losses in a right-angled confluence of an open channel with rectangular cross-sections.A large eddy simulation (LES)-based numerical model was set up and validated with experiments by others.Four configurations with different bed discordance ratios were investigated.The results confirm that, with increasing bed elevation discordance, the tributary streamlines at the confluence interface deviate less from the geometrical confluence angle, the extent of the recirculation zone (RZ) gets smaller, the ratio of the water depth upstream to that downstream of the confluence decreases, and the water level depression reduces.The bed elevation discordance also leads to the development of a large-scale structure in the lee of the step.Despite the appearance of the large-scale structure, the reduced extent of the RZ and associated changes in flow deflection/contraction reduce total head losses experienced by the main channel with an increase of the bed discordance ratio.It turns out that bed elevation discordance converts the lateral momentum from the tributary to streamwise momentum in the main channel more efficiently.

Controlling quantum discord dynamics in cavity QED systems by applying a classical driving field with phase decoherence

We investigate a two=level atom interacting with a quantized cavity field and a classical driving field in the presence of phase decoherence and find that a stationary quantum discord can arise in the interaction of the atom and cavity field as the time turns to infinity. We also find that the stationary quantum discord can be increased by applying a classical driving field. Furthermore, we explore the quantum discord dynamics of two identical non=interacting two-level atoms independently interacting with a quantized cavity field and a classical driving field in the presence of phase decoherence. Results show that the quantum discord between two atoms is more robust than entanglement under phase decoherence and the classical driving field can help to improve the amount of quantum discord of the two atoms.

Discord在光子晶体中的演化特性研究

研究了两个原子分别放置在两光子晶体热库中的量子关联。在这个系统中,描述了discord和concurrence处在不同初态下随着失谐量δ变化关系,并比较它们的区别和联系,发现当同时结合discord和concurrence描述时,可以得出非纠缠量子关联的变化趋势。最后对所得现象进行了分析。

Quantum correlation dynamics in a two-qubit Heisenberg XY Z model with decoherence

Quantum correlation dynamics in an anisotropic Heisenberg XYZ model under decoherence is investigated by making use of concurrence C and quantum discord （QD）. Firstly, we show that both the concurrence and QD exhibit oscillation with time whereas a remarkable difference between them is presented： there is an ＂entanglement intermittently sudden death＂ phenomenon in the concurrence but not in the QD, which is valid for all the initial states of this system. Also, the interval time of entanglement sudden death is found to be strongly dependent on the initial states, the inhomogeneous magnetic field b and the anisotropic parameter △. Then, it implies that the steady concurrence and QD can be obtained in the long-time limit, which means that the environmental decoherence cannot entirely destroy the quantum correlation, the variation of the uniform magnetic field B and the anisotropic parameter can change the magnitude of the steady concurrence and QD evidently whereas the parameter b cannot. In addition, based on the analysis of the steady concurrence and QD with t →∞, we give the reason why the magnitude of the steady concurrence and QD is so complicated with the change of the parameters B and .4, whereas the parameter b is independent of the steady concurrence and QD.

Research on the Freezing Phenomenon of Quantum Correlation by Machine Learning

Quantum correlation shows a fascinating nature of quantum mechanics and plays an important role in some physics topics,especially in the field of quantum information.Quantum correlations of the composite system can be quantified by resorting to geometric or entropy methods,and all these quantification methods exhibit the peculiar freezing phenomenon.The challenge is to find the characteristics of the quantum states that generate the freezing phenomenon,rather than only study the conditions which generate this phenomenon under a certain quantum system.In essence,this is a classification problem.Machine learning has become an effective method for researchers to study classification and feature generation.In this work,we prove that the machine learning can solve the problem of X form quantum states,which is a problem of physical significance.Subsequently,we apply the density-based spatial clustering of applications with noise(DBSCAN)algorithm and the decision tree to divide quantum states into two different groups.Our goal is to classify the quantum correlations of quantum states into two classes:one is the quantum correlation with freezing phenomenon for both Rènyi discord(α=2)and the geometric discord(Bures distance),the other is the quantum correlation of non-freezing phenomenon.The results demonstrate that the machine learning method has reasonable performance in quantum correlation research.

Thermal quantum discord in Heisenberg models with Dzyaloshinski-Moriya interaction

We study the quantum discord of the bipartite Heisenberg model with the Dzyaloshinski-Moriya （DM） interaction in thermal equilibrium state and discuss the effect of the DM interaction on the quantum discord. The quantum entanglement of the system is also discussed and compared with quantum discord. Our results show that the quantum discord may reveal more properties of the system than quantum entanglement and the DM interaction may play an important role in the Heisenberg model.

HER2 discordance between paired primary gastric cancer and metastasis:a meta-analysis

Background： A number of studies have examined human epidermal growth factor receptor 2 （HER2） status in primary gastric cancer （GC） and associated metastasis, some showed their great concordance in FIER2 expression, but others demonstrated notable discordance. There is still little consensus on HER2 discordance, therefore, a systematic review and meta-analysis was conducted to assess the status on HER2 discordance between primary GC and its paired metastasis. Methods： PubMed, EMBASE, ASCO and The Cochrane Library were searched for studies that explored the concordance between primary tumor and metastasis in patients with GC up to 10 March, 2014. Data of discordance of HER2 between primary GC and corresponding metastasis were extracted from the publications and random-effects models were used to estimate pooled discordance proportions. Results： Eighteen articles including 1,867 patients were included for the meta-analysis in accordance with the selection criteria. Pooled discordance proportions were 7% [95% confidence interval （CI）： 5-10%] for HER2 status. Pooled proportions of tumors shifting from positive to negative and from negative to positive were 17% （95% CI： 7-29%） and 4% （95% CI： 2-6%） respectively. No publication bias was found in the meta-analysis. Conclusions： The discordance of HER2 status is not rare in primary and metastatic GC through our metaanalysis. Prospective studies are needed to testify the clinical significance of the discordance of HER2 status.

两体非马尔科夫环境下的quantum discord研究

研究了两个相互独立的原子在非马尔科夫环境下的动力学。发现在一些初态下随着参数δ(原子频率与边带频率的失谐量)减小到一定程度后quantum diSicord会衰减到一个稳定值,并且这个稳定值会随着参数δ的减小而增大。这说明在一段时间内耗散能够被有效的抑制。在部分初态下,Concurrence消失而quarttum discord依然保持在一定数值,说明此时quarttum discord所描述的是非纠缠的部分,此外quantum discord中的非纠缠部分时间演化受到所选取的初态的影响。