两体高维系统Negativity的研究

首先从理论上对Negativity的两种定义进行比较,然后推导出二参量两体高维量子系统Negativity的表达式.

两体高维量子系统的Negativity

量子纠缠及其度量在量子通讯中起着至关重要的作用.文章采用一种量子纠缠的计算方法—Negativity,推导得到了二参量两体高维量子系统Negativity的一般解析表达式.此方法的优点是计算方便,物理意义明确.

Detection of cognitive impairment in patients with obstructive sleep apnea hypopnea syndrome using mismatch negativity

In this experiment, 97 patients with obstructive sleep apnea hypopnea syndrome were divided into three groups （mild, moderate, severe） according to minimum oxygen saturation, and 35 healthy subjects were examined as controls. Cognitive function was determined using the mismatch negativity paradigm and the Montreal Cognitive Assessment. The results revealed that as the disease worsened, the mismatch negativity latency was gradually extended, and the amplitude gradually declined in patients with obstructive sleep apnea hypopnea syndrome. Importantly, mismatch negativity latency in severe patients with a persistent time of minimum oxygen saturation 〈 60 seconds was significantly shorter than that with a persistent time of minimum oxygen saturation 〉 60 seconds. Correlation analysis revealed a negative correlation between minimum oxygen saturation latency and Montreal Cognitive Assessment scores. These findings indicate that intermittent night-time hypoxemia affects mismatch negativity waveforms and Montrea Cognitive Assessment scores. As indicators for detecting the cognitive functional status of obstructive sleep apnea hypopnea syndrome patients, the sensitivity of mismatch negativity is 82.93%, the specificity is 73.33%, the accuracy rate is 81.52%, the positive predictive value is 85.00%, the negative predictive value is 70.21%, the positive likelihood ratio is 3, and the negative likelihood ratio is 0.23. These results indicate that mismatch negativity can be used as an effective tool for diagnosis of cognitive dysfunction in obstructive sleep apnea hypopnea syndrome patients.

Geometrical quantum discord and negativity of two separable and mixed qubits

We studied quantum correlation and quantum entanglement of a quantum system in which a coherent state light field interacts with two qubits that are initially prepared in a separable and mixed state.The influence of mean photon number of the coherent field and distribution probability of the atom on the geometrical quantum discord and the negativity are discussed.Our results show that the mean photon number of light field and distribution function of the atom can regulate and control the quantum correlation and quantum entanglement.

Superiority Effect in Detecting Phylogenetic Threats Under Unattentional Condition: A Visual Mismatch Negativity Study

Rapid and accurate perception of threat information is a critical ability and a prerequisite to survive natural selection for humans.To investigate whether threatening stimuli,especially phylogenetic and ontogenetic threats,are processed automatically,we analyzed the visual mismatch negativity(vMMN,an event-related potential component reflecting automatic processing)elicited by the threats with a cross-modal oddball paradigm,where participants were required to focus on the auditory stimuli and ignore the visual stimuli in each block.In this study,neutral(non-threatening)images served as standard stimuli(80%),and phylogenetic(10%)and ontogenetic(10%)threat stimuli served as deviant stimuli when testing a large sample(N=96)of healthy volunteers.Threat-related visual mismatch negativity(threat-vMMN)was obtained by subtracting the event-related potential(ERP)elicited by standard stimuli from that elicited by deviant stimuli.The results indicated that the vMMN can be elicited by threat information.More importantly,the phylogenetic threat information elicited larger threat-vMMN than ontogenetic threat information.These findings suggest that perception of threat information was automatic,providing an evidential basis for the attentional advantages of survival processing.That is,automatic perception of phylogenetic threats has a particular evolutionary origin.

Effect of escitalopram on cognitive function in depressionA mismatch negativity potentials study

We detected the event-related potential mismatch negativity （MMN） of 30 depression patients and compared to 30 age,gender,and education-matched healthy controls.Results showed that amplitudes of frequency and duration MMN were lower in depression patients compared with control patients,indicating abnormality in auditory processing （i.e.,cognitive impairment）.Following escitalopram treatment for 8 weeks,the amplitudes of frequency and duration MMN were significantly increased and Hamilton Rating Scale for Depression scores were significantly decreased in depression patients.These data suggest that escitalopram can improve cognitive function of patients with depression.Further,MMN may be a useful tool for evaluating cognitive function and treatment effects.

On extending the concept of double negativity to acoustic waves

The realization of double negative electromagnetic wave media, sometimes called left-handed materials (LHMs) or metamaterials, have drawn considerable attention in the past few years. We will examine the possibility of extending the concept to acoustic waves. We will see that acoustic metamaterials require both the effective density and bulk modulus to be simultaneously negative in the sense of an effective medium. If we can find a double negative (negative density and bulk modulus) acoustic medium, it will be an acoustic analogue of Veselago’s medium in electromagnetism, and share many novel consequences such as negative refractive index and backward wave characteristics. We will give one example of such a medium.

Monogamous nature of symmetric N-qubit states of the W class: Concurrence and negativity tangle

Using Majorana representation of symmetric N-qubit pure states, we have examined the monogamous nature of the family of states with two-distinct spinors, the W class of states. We have evaluated the N-concurrence tangle and showed that all the states in this family have vanishing concurrence tangle. The negativity tangle for the W class of states is shown to be non-zero, illustrating the fact that the concurrence tangle is always lesser than or equal to the negativity tangle in a pure N-qubit state.

Qubit-qutrit海森堡混合自旋链系统QMA熵不确定度的量子调控

在qubit-qutrit海森堡混合自旋链模型中研究了量子存储支撑(Quantum memory assisted,QMA)熵不确定度的量子调控.详细分析了混合自旋链模型中的Dzyaloshinskii-Moriya(DM)相互作用、耦合强度和非均匀磁场对QMA熵不确定度的影响,对比分析了混合自旋链模型中系统参数对QMA熵不确定度和被测系统与存储系统的量子纠缠的调控作用.结果表明,通过调控非均匀磁场强度和混合自旋链系统的参数,可以提高被测系统与存储系统的量子纠缠,降低系统QMA熵不确定度及其下限.

Quantum correlations and entanglement in coupled optomechanical resonators with photon hopping via Gaussian interferometric power analysis

Quantum correlations that surpass entanglement are of great importance in the realms of quantum information processing and quantum computation.Essentially,for quantum systems prepared in pure states,it is difficult to differentiate between quantum entanglement and quantum correlation.Nonetheless,this indistinguishability is no longer holds for mixed states.To contribute to a better understanding of this differentiation,we have explored a simple model for both generating and measuring these quantum correlations.Our study concerns two macroscopic mechanical resonators placed in separate Fabry–Pérot cavities,coupled through the photon hopping process.this system offers a comprehensively way to investigate and quantify quantum correlations beyond entanglement between these mechanical modes.The key ingredient in analyzing quantum correlation in this system is the global covariance matrix.It forms the basis for computing two essential metrics:the logarithmic negativity(E_(N)^(m))and the Gaussian interferometric power(P_(G)^(m)).These metrics provide the tools to measure the degree of quantum entanglement and quantum correlations,respectively.Our study reveals that the Gaussian interferometric power(P_(G)^(m))proves to be a more suitable metric for characterizing quantum correlations among the mechanical modes in an optomechanical quantum system,particularly in scenarios featuring resilient photon hopping.

EAST装置中新型吸附剂泵(NEG)抽速标定研究

粒子排出是控制燃料粒子再循环、提升等离子体性能的关键因素之一。因此研究了新型吸附剂泵(NEG)在粒子排出技术中的潜在应用。NEG泵基于ZAO新型合金材料制成,对氢及其同位素抽速大、容量高,安装、运行、维护简单,兼容等离子体环境,适用于偏滤器区域的超高热流和复杂的空间结构。在EAST托卡马克装置安装4套HV800模组,开展了定期的抽速标定、再生研究以评估其周期性能变化。EAST真空室壁表面积较大,金属壁放气、杂质气体影响NEG泵抽速计算。通过计算EAST整体漏放率与氢及其同位素放气率,利用计算机模拟抽气过程,提出了一种用于修正NEG泵抽速的方法。研究结果表明在偏滤器区域工作压力下,对氘平均抽速可达1200 L/s。

Spatial Properties of Mismatch Negativity in Patients with Disorders of Consciousness

In recent decades, event-related potentials have been used for the clinical electrophysiological assessment of patients with disorders of consciousness （DOCs）. In this paper, an oddball paradigm with two types of frequencydeviant stimulus （standard stimuli were pure tones of 1000 Hz; small deviant stimuli were pure tones of 1050 Hz; large deviant stimuli were pure tones of 1200 Hz） was applied to elicit mismatch negativity （MMN） in 30 patients with DOCs diagnosed using the JFK Coma Recovery Scale- Revised （CRS-R）. The results showed that the peak amplitudes of MMN elicited by both large and small deviant stimuli were significantly different from baseline. In terms of the spatial properties of MMN, a significant interaction effect between conditions （small and large deviant stimuli） and electrode nodes was centered at the frontocentral area. Furthermore, correlation coefficients were calculated between MMN amplitudes and CRS-R scores for each electrode among all participants to generate topographic maps. Meanwhile, a significant negative correlation between the MMN amplitudes elicited by large deviant stimuli and the CRS-R scores was also found at the frontocentral area. In consequence, our results combine the above spatial properties of MMN in patients with DOCs, and provide a more precise location （frontocentral area） at which to evaluate the correlation between clinical electrophysiological assessment and the level of consciousness.

Attentional negativity bias moderated by positive mood arousal

Automatically allocation of more attention to negative stimuli is called emotional negativity bias.An event-related potentials(ERPs) experiment investigated whether or not this bias was altered by positive mood arousal.The results suggested that the attention bias towards negative stimuli was attenuated when positive information was accessible.

Neurophysiological predictors of aphasia recovery in patients with large left-hemispheric infarction: a mismatch negativity study

Background:Although the rehabilitation of aphasia has been extensively studied,the prediction of language outcome still has not received sufficient attention.The aim of this study was to predict the language outcome using mismatch negativity(MMN)in patients with large left-hemispheric infarction.Methods:MMN was elicited by an oddball paradigm in which a standard tone(1000 Hz)and deviant tone(1500 Hz)were presented at 90%and 10%of the number of tones,respectively.The mean amplitudes and laterality indexes(LIs)of MMN were measured over the prefrontal,frontal,central,parietal,temporal,and perisylvian electrodes and both hemispheres during the first 7 days(session 1)and 10 to 20 days(session 2)post-onset.Mixed three-way analysis of variance(ANOVA)was used to investigate differences in these factors between two aphasia groups(the good recovery group and poor recovery group).The predictive value of the most significant LI was also compared with the score of National Institutes of Health Stroke Scale score and low-density volume on computed tomography.Results:A total of 18 patients were enrolled in this study.Mixed three-way ANOVA showed no interaction effect of session×region of interest(ROI)×group(F[3.59,57.38]=1.301,P=0.282)and no interaction effect of ROI×group(F[1.81,29.01]=0.71,P=0.487)and session×group(F[1.00,16.00]=0.084,P=0.776)for MMN amplitude.No interaction effect of session×ROI×group(F[1.79,28.58]=0.62,P=0.530),but an interaction effect of session×group(F[1.00,16.00]=5.21,P=0.036)was found for LIs.In the poor recovery group,the LIs of MMN over all the ROIs,except the parietal area,became more negative at session 2 than those at session 1(P<0.05),but this effect was not observed in the good recovery group.Additionally,significant differences were observed in the LIs at session 2 between the two groups(P<0.05).The LI over the perisylvian area at session 2 had the highest predictive value with an area under the curve of 0.963(95%confidence interval:0.884–1.000).An LI score>-0.36 over the perisylvian area suggested good recovery,but a score<-0.36 suggested poor recovery.The LI cut-off value of-0.36 had the highest sensitivity(90.0%)and specificity(87.5%)for predicting a good language outcome at 3 months post-stroke.Conclusion:LIs of MMN amplitudes at approximately 2 weeks post left-hemisphere stroke serve as more sensitive predictors of language outcome,among which the LI over the perisylvian area exhibits the best predictive value.

差压法测定NEG吸氢性能

通过对定压法进行改进提出了差压法,用于测试非蒸散型吸气剂(NEG)的吸氢性能。该方法在进气室和吸气室之间安装固定流导元件,利用调节微调阀提供可控的进气流量,通过测量吸气室、进气室和参考室的压力计算NEG的吸气性能参数。利用两种NEG比较了差压法和改进的定压法所测吸气性能。结果表明:差压法测得的吸气容量比改进的定压法测得的吸气容量低0.07268 Pa·L;腔室壁面吸附能力使改进定压法的试验结果高于理论结果,而差压法的试验结果不受影响;对改进的定压法进行优化后,其计算结果与差压法的接近。差压法可以获得更准确、更有效的吸气剂性能参数,在差压法中,参考部分和试验部分同时进行测试,可缩短测试时间,减少控制进气带来的误差。

Design of double negativity elastic metamaterial

A metamaterial model that possesses simultaneously negative effective mass density and negative effective Young’s modulus is proposed in this study.Dispersion curves and dynamic responses of the model are investigated.In the double negative frequency region,it is demonstrated that the phase velocity is negative.In addition,it was found that the band gap region of the metamaterial can be predicted accurately by taking parts of single-unit cell to analyze the steady-state response.The design is also fabricated by a 3D printer.

Mismatch negativity of ERP in cross-modal attention

Event-related potentials were measured in 12 healthy youth subjects aged 19-22 using the paradigm 'cross-modal and delayed response' which is able to improve unattended purity and to avoid the effect of task target on the deviant components of ERP. The experiment included two conditions: (i) Attend visual modality, ignore auditory modality; (ii) attend auditory modality, ignore visual modality. The stimuli under the two conditions were the same. The difference wave was obtained by subtracting ERPs of the standard stimuli from that of the deviant stim-uli. The present results showed that mismatch negativity (MMN), N2b and P3 components can be produced in the auditory and visual modalities under attention condition. However, only MMN was observed in the two modalities un-der inattention condition. Auditory and visual MMN have some features in common: their largest MMN wave peaks were distributed respectively over their primary sensory projection areas of the scalp under attention condition, but over fronto-central scalp under inattention condition. There was no significant difference between the amplitudes of visual and auditory MMN. Their amplitudes and the scalp distribution were unaffected by attention, thus suggesting that MMN amplitude is an important index reflecting automatic processing in the brain. However, the latency of the audi-tory and visual MMN were affected by attention, showing that MMN not only reflects automatic processing but also probably relates to control processing.

Monogamy Relations for Squared Entanglement Negativity

This paper contains two main contents.In the first part,we provide two counterexamples of monogamy inequalities for the squared entanglement negativity:one three-qutrit pure state which violates of the He–Vidal monogamy conjecture,and one four-qubit pure state which disproves the squared-negativity-based Regula–Martino–Lee–Adessoclass strong monogamy conjecture.In the second part,we investigate the sharing of the entanglement negativity in a composite cavity-reservoir system using the corresponding multipartite entanglement scores,and then we find that there is no simple dominating relation between multipartite entanglement scores and the entanglement negativity in composite cavity-reservoir systems.As a by-product,we further validate that the entanglement of two cavity photons is a decreasing function of the evolution time,and the entanglement will suddenly disappear interacting with independent reservoirs.

Amino-functionalized UiO-66-doped mixed matrix membranes with high permeation performance and fouling resistance

For the reduction of bovine serum proteins from wastewater,a novel mixed matrix membrane was prepared by functionalizing the substrate material polyaryletherketone(PAEK),followed by carboxyl groups(C-SPAEKS),and then adding amino-functionalized UiO-66-NH_(2)(Am-UiO-66-NH_(2)).Aminofunctionalization of UiO-66 was accomplished by melamine,followed by an amidation reaction to immobilize Am-UiO-66-NH_(2),which was immobilized on the surface of the membrane as well as in the pore channels,which enhanced the hydrophilicity of the membrane surface while increasing the negative potential of the membrane surface.This nanoparticle-loaded ultrafiltration membrane has good permeation performance,with a pure water flux of up to 482.3 L·m^(-2)·h^(-1) for C-SPAEKS/AmUiO-66-NH_(2) and a retention rate of up to 98.7%for bovine serum albumin(BSA)-contaminated solutions.Meanwhile,after several hydrophilic modifications,the flux recovery of BSA contaminants by this series of membranes increased from 56.2%to 80.55%of pure membranes.The results of ultra-filtration flux time tests performed at room temperature showed that the series of ultrafiltration membranes remained relatively stable over a test time of 300 min.Thus,the newly developed mixed matrix membrane showed potential for high efficiency and stability in wastewater treatment containing bovine serum proteins.

Negativity of Quantumness and Non-Markovianity in a Qubit Coupled to a Thermal Ising Spin Bath System

We propose a scheme to characterize the non-Markovian dynamics and quantify the non-Markovianity via the non-classicality measured by the negativity of quantumness. By considering a qubit in contact with a critical Ising spin bath and introducing an ancilla, we show that revivals of negativity of quantumness indicate the non-Markovian dynamics.Furthermore, a normalized measure of non-Markovianity based on the negativity of quantumness is introduced and the influences of bath criticality, bath temperature and bath size on the non-Markovianity are discussed. It is shown that,at the critical point, the decay of non-Markovianity versus the size of spin bath is the fastest and the non-Markovianity is exactly zero only in the thermodynamic limit. Besides, non-trivial behaviours of negativity of quantumness such as sudden change, double sudden changes and keeping constant are found for different relations between parameters of the initial state. Finally, how the non-classicality of the system is affected by a series of bang-bang pulses is also examined.