Quasiparticle Research Articles

Effect of collective spin excitations on electronic transport in topological spin textures

Effect of collective spin excitations on electronic transport in topological spin textures

Ultralow-Frequency Tip-Enhanced Raman Scattering Discovers Nanoscale Radial Breathing Mode on Strained 2D Semiconductors.

Collective excitations including plasmons, magnons, and layer-breathing vibration modes emerge at an ultralow frequency (<1 THz) and are crucial for understanding van der Waals materials. Strain at the nanoscale can drastically change the property of van der Waals materials and create localized states like quantum emitters. However, it remains unclear how nanoscale strain changes collective excitations. Herein, ultralow-frequency tip-enhanced Raman spectroscopy (TERS) with sub-10nm resolution under ambient conditions is developed to explore the localized collective excitation on monolayer semiconductors with nanoscale strains. A new vibrational mode is discovered at around 12 cm-1 (0.36 THz) on monolayer MoSe2 nanobubbles and it is identified as the radial breathing mode (RBM) of the curved monolayer. The correlation is determined between the RBM frequency and the strain by simultaneously performing deterministic nanoindentation and TERS measurement on monolayer MoSe2. The generality of the RBM in nanoscale curved monolayer WSe2 and bilayer MoSe2 is demonstrated. Using the RBM frequency, the strain of the monolayer MoSe2 on the nanoscale can be mapped. Such an ultralow-frequency vibration from curved van der Waals materials provides a new approach to study nanoscale strains and points to more localized collective excitations to be discovered at the nanoscale.

Bound Bogoliubov quasiparticles in photon superfluids

Bogoliubov's description of Bose gases relies on the linear dynamics of noninteracting quasiparticles on top of a homogeneous condensate. Here, we theoretically explore the weakly nonlinear regime of a one-dimensional photon superfluid in which phononlike elementary excitations interact via their backreaction on the background flow. The generalized dispersion relation extracted from spatiotemporal intensity spectra reveals additional branches that correspond to Bogoliubov quasiparticles—phase-locked collective excitations originating from nonresonant harmonic generation and wave-mixing processes. These mechanisms are inherent to fluctuation dynamics and highlight nontrivial scattering channels other than resonant interactions that could be relevant in the emergence of dissipative and turbulent phenomena in superfluids. Published by the American Physical Society 2024

Validation of the Chinese Empathy Questionnaire for Pre-School Children

ABSTRACT Research Findings: Empathy plays an important role in children’s early social-emotional development. However, there are not many instruments available for measuring the different aspects/levels of empathy in preschool children. Moreover, few studies examined the validity of the existing measures for empathy in Chinese children. The present study tested the Chinese version of the Empathy Questionnaire (EmQue) upon a group of Chinese preschool children (N = 182) aged from 2 to 6 years. The Chinese EmQue is a parent-report translated from Dutch that assesses the behavioral manifestations of three distinct levels of empathy: emotion contagion, attention to others’ feelings, and prosocial behaviors among preschool children. Confirmatory factor analysis showed satisfactory goodness-of-fit indexes for a three-level structure with 19 loading items. The results of concurrent validity showed that the three levels of empathy were functioning differently in the early social-emotional development. Practice or Policy: We could conclude that the 19-item Chinese EmQue is a valid, reliable instrument for measuring empathy in 2- to 6-year-old children in the Chinese context.

Entropy production rate and correlations in a cavity magnomechanical system

We present the irreversibility generated by a stationary cavity magnomechanical system composed of a yttrium iron garnet (YIG) sphere with a diameter of a few hundred micrometers inside a microwave cavity. In this system, the magnons, i.e., collective spin excitations in the sphere, are coupled to the cavity photon mode via magnetic dipole interaction and to the phonon mode via magnetostrictive force (optomechanical-like). We employ the quantum phase-space formulation of the entropy change to evaluate the steady-state entropy production rate and associated quantum correlation in the system. We find that the behavior of the entropy flow between the cavity photon mode and the phonon mode is determined by the magnon-photon coupling and the cavity photon dissipation rate. Interestingly, the entropy production rate can increase/decrease depending on the strength of the magnon-photon coupling and the detuning parameters. We further show that the amount of correlations between the magnon and phonon modes is linked to the irreversibility generated in the system for small magnon-photon coupling. Our results demonstrate the possibility of exploring irreversibility in driven magnon-based hybrid quantum systems and open a promising route for quantum thermal applications. Published by the American Physical Society 2024

Collective excitation of quantum droplet with different ranges of the interaction of Pöschl-Teller potential

In this article, we studied quantum droplet with the Pöschl-Teller (PT) interaction potential between the Bose atoms. The Gross–Pitaevskii (GP) equation governs the system. The range and strength of the PT interaction can be adjusted. First, we studied the quantum droplet’s density variation for various PT interaction parameters by the imaginary-time split-step Crank-Nicolson (CN) method. We then used the Bogoliubov theory to examine the collective excitation spectra. We observed that sharp roton forms and phonon modes are missing during long-range interactions. There is a gap at the zero momentum zone due to the long-range PT interaction, which increases with the range and strength of the interaction.

Spectroscopy of N = 50 isotones with the valence-space density matrix renormalization group

The recently proposed combination of the valence-space in-medium similarity renormalization group (VS-IMSRG) with the density matrix renormalization group (DMRG) offers a scalable and flexible many-body approach for strongly correlated open-shell nuclei. We use the VS-DMRG to investigate the low-lying spectroscopy of N=50 isotones, which are characteristic for their transition between single-particle and collective excitations. We also study electromagnetic transitions and show the advantage of the VS-DMRG to capture the underlying physics more efficiently, with significantly improved convergence compared to state-of-the-art shell-model truncations. Combined with an analysis of quantum information measures, this further establishes the VS-DMRG as a valuable method for ab initio calculations of nuclei.

Group emotions and their role in EU foreign policy: a social relational model on how emotions travel between EU member states

ABSTRACT EU foreign policy is highly dependent on EU member states, but we still lack a coherent conceptual framework that does justice to the interdependences and co-constitutive relations between EU countries. Building on relational theory and social psychology, we develop a social relational model about group emotions in the Council that conceptualises under what conditions emotions play a role in EU foreign policy decision-making. We formulate scope conditions detailing when the performance of emotions might allow member states to accumulate relational power (e.g. process power), which can in turn allow for the emergence of group emotions and even drive policy changes. Most notably, we shed light on group dynamics within the Council, determining if and how group emotions inform the EU´s policy response to norm contestation. Our framework helps understand why processes of emotional appraisal, contagion, and emergence might sometimes help propel the EU into action, whereas other times they seem to have little or no effect.

Social Media, Sentiments and Political Discourse ? An Exploratory Study of the 2021 Canadian Federal Election

Social media are widely used for online political discourse. Opinions shared on social media have different sentiments associated with them. Given the very high adoption rates of Twitter (now X) among adults, those who share their opinions on Twitter (X) not only represent a sizable segment of the society, but also influence (through emotion contagion) an even larger segment who are passive (non-contributing) users of the platform. Further, the discourse that is initiated on Twitter (X) typically spreads to other more traditional media. As a result, Twitter (X) is influential, which makes it useful to understand the factors related to the sentiments expressed in tweets. Such understanding can help policymakers to take actions that align with public needs and priorities. This research focuses on identifying the drivers (keywords) of sentiments associated with political discourse on Twitter (X). We also explore virality, i.e., how much a message (the tweet) spreads, and the relationship between sentiments and virality. Finally, we explore whether the clustering of tweets among sentiment and virality groups can improve the potential of social media content for predicting election results. Sentiment Analysis of 764,000 tweets related to the 2021 Canadian Federal election was followed by text clustering to identify sentiment-driving topics. We found some keywords predominantly present within a positive or negative sentiment that are suggestive of entities or ideas to invest in or mitigate by political decision makers. We were also able to find partial evidence for “negativity bias” by detecting a negative relationship between sentiment (positivity) and virality (number of retweets). Finally, we demonstrated that high positivity on the political discourse does not reflect election outcomes and examining Twitter (X) content in more neutral groups can improve predictive power. Our findings have implications for political decision makers and social media analytics researchers.

Physiological state matching in a pair bonded poison frog.

More than a century ago, Charles Darwin hypothesized that theempathy-like phenotype is a phylogenetically widespread phenomenon. This idea remains contentious, due to the challenges of empirically examining emotions, and few investigations among non-mammalian vertebrates. We provide support for Darwin's hypothesis by discovering partial evidence for the most ancestral form of empathy, emotional contagion (i.e. matching another individual's emotional state), in the pair bonding mimetic poison frog, Ranitomeya imitator. We found that male corticosterone, a physiological biomarker of stress, positively correlates with female partners in experimental and semi-natural conditions. This does not appear to coincide with behavioural state-matching. However, it is specific to female partners relative to familiar female non-partners, and is independent of effects that commonly confound studies on emotional contagion. Furthermore, this physiological state-matching is irrespective of partnership longevity or lifetime reproductive output. These results physiologically indicate socially selective emotional contagion in a monogamous amphibian, and paradigms that elicit coinciding neural and behavioural indicators and morphogenic co-variation are needed for further corroboration. Further studies on ancestral forms of empathy in non-mammalian vertebrates are warranted.

Study of Spin-Polarization Effects of Collective Excitations in Double-Layer GrapheneStructures

Study of Spin-Polarization Effects of Collective Excitations in Double-Layer GrapheneStructures

British small talk as an ecolinguistic phenomenon

The article analyzes modern small talk as a way of establishing contacts, which is typical for British linguistic culture, as it manifests the speaker’s wish to achieve emotional and intellectual understanding and create a friendly atmosphere at the initial phase of the conversation, especially when it is necessary to avoid long and inconvenient silence. Speech clichés, etiquette formulas for establishing and maintaining communicative contact, as well as specific topics for discussions are determined by the socio-ethical norms of the British cultural community. Interlocutors are guided by the goals of regulating social contacts, serving the purpose of strengthening contacts. The limits of phaticity in the contact-establishing phase of social conversation and the transition to informativeness in the process of conversation depend on a type of discourse, a type of situation, and communicative goals of the speakers. Under the conditions of the situation threatening the speakers’ lives, or a change from an ecological unison model of communication to a non-ecological dissonant one, the speakers’ rejection from phaticism in the phase of establishing contact in favor of informativeness has been observed. British communicative culture ensures the balance of the ecosystem due to the use of a significant number of linguistic elements ensuring the implementation of harmonious communication: polite forms of encouragement instead of the use of the Imperative Mood which sounds too categorical for British culture, disjunctive questions that combine both the features of interrogative and affirmative statements, superlative forms of adjectives. Small talk components, such as the ability to listen, minimal transmission of negative emotions, limited or zero use of negatively colored vocabulary, the creation of a safe and convenient atmosphere of communication, observance of the personal boundaries of the interlocutor, the interest in what the interlocutors say, as well as sincerity correspond to the main principles of ecological communication.

A dataset of SEM images of atmospheric particles in Qingdao

In this paper, we selected seven representative sampling points in Qingdao to collect atmospheric particulate samples in different periods, and then obtained the SEM (Scanning Electron Microscope) images of particulate matters through scanning electron microscopy. By observing and analyzing the morphological characteristics of the images, we identified and selected 334 SEM images of particles with distinct morphological characteristics. Based on the obtained SEM images of atmospheric particles, the particles are divided into seven categories according to their morphological characteristics: chain particles, flocculent particles, fibrous particles, spherical particles, quasi spherical particles, irregular mineral particles, and regular mineral particles. These obtained SEM images are further enhanced using corresponding image processing methods such as horizontal inversion, color balance, brightness transformation, fuzzy processing, etc. New image samples are generated and added to the dataset, presenting a dataset of SEM images for seven types of atmospheric particles, totaling 2,672 SEM images in total. The dataset can be used for identifying, classifying, segmenting research on atmospheric particles using machine learning and other related methods. Moreover, it can provide fundamental data for other related research on atmospheric particles.

How Narcissism and Susceptibility to Emotional Contagion Affect Belief in Fake News on Social Media from a Dual Information Processing Perspective: A Hybrid SEM and ANN Approach

Objectives: To answer who believes in fake news and provide strategies to combat it, we examined how narcissism and susceptibility to emotional contagion influences belief in fake news on social media through heuristic and systematic processing; we also evaluated the moderating effect of media literacy. In addition, we ranked the relative importance of these factors to belief in fake news. Methods: We used a hybrid structural equation modeling (SEM) and artificial neural networks (ANN) approach to analyze data collected from 347 respondents in an online survey. Results: The SEM results showed that narcissism and susceptibility to emotional contagion positively influenced heuristic and systematic processing, thus positively influencing belief in fake news. Media literacy moderated the relationship between systematic processing and belief in fake news. Conclusion: The ANN results indicated that narcissism is a more critical factor for belief in fake news. ANN predicted belief in fake news with an accuracy of 99.9%.

Towards a Theory of Emotional Autonomy

The author challenges the emotional contagion theory and proposes an alternative of emotional autonomy. He critiques how the contagion theory is faulty logic because it assumes different individuals may experience identical emotions, rather than each having their own phenomenological experience even though the outward signs may look similar. A way of ascertaining individual experiences of emotions is suggested, followed by an example of the experiences of pain, before the conclusion that we should adopt within the literature the assumptions of emotional autonomy.

Family-customer happiness and its impact on customer citizenship behavior: A study of parent–child consumption in robot restaurants

Academic research on ways to promote family consumers' happiness in technology-enabled service contexts is limited. Based on the value co-creation concept and emotional contagion theory, this study focuses on parent-child consumption and develops a theoretical model of the relationship between customer–robot interaction experience, family emotional bonding, customer happiness, and citizenship behavior in robot restaurants. Further insights into the model were obtained by content analysis of 374 online customer reviews, and the model was tested by a questionnaire survey of 515 family customers. The results of structural model analysis show that customer-perceived child delight and customer engagement in robot services have direct and indirect effects on customer happiness through the enhancement of family emotional bonding. Customer happiness positively affects customer citizenship behavior and mediates the relationship between family emotional bonding and customer citizenship behavior. The study provides guidance for using robotics to promote the happiness of customers and prosperity of restaurants.

Diffusive decay of collective quantum excitations in electron gas

Diffusive decay of collective quantum excitations in electron gas

The Impact of Actor's Belief on Audience Emotional Resonance and Emotional Transmission

This study examines the impact of actors' Belief on Emotional Resonance and Emotional Transmission of the audience, revealing the key role of Belief in the performing arts. Belief is the actor's ability to regard fictional situations and characters as real in the performance process, which makes the performance strongly infectious and authentic. Through Belief, actors are able to realize a high degree of integration between their characters and themselves, thus impressing the audience and creating Emotional Resonance. This study analyzes the impact of Belief on performance effect, characterization and emotional expression, explores the interactive mechanism of Emotional Transmission and Resonance, enhances the understanding of performance psychology, and reveals the complex interactive relationship between the performing arts and audience psychology.

Shear wave propagation in a liquid crystal: An inelastic X-ray scattering study.

We investigated the spectrum of density fluctuations of a liquid crystal, CB7CB, in two different orientations by using high-resolution inelastic x-ray scattering. Our analysis, based on Bayesian principles, revealed that high-frequency collective excitations propagate through this mesoscale-ordered sample in a peculiar manner that lies somewhere between those observed in liquids and crystalline systems. Interestingly, when we probed longer length scales, a more pronounced solid-like response emerged. This was mainly characterized by anomalously sharp inelastic excitations and the onset of shear mode propagation. Comparison with previous x-ray diffraction results suggests a correlation between the observed behavior and the mesogen arrangement.

Revealing Novel Aspects of Light-Matter Coupling by Terahertz Two-Dimensional Coherent Spectroscopy: The Case of the Amplitude Mode in Superconductors.

Recently developed terahertz (THz) two-dimensional coherent spectroscopy (2DCS) is a powerful technique to obtain materials information in a fashion qualitatively different from other spectroscopies. Here, we utilized THz 2DCS to investigate the THz nonlinear response of conventional superconductor NbN. Using broadband THz pulses as light sources, we observed a third-order nonlinear signal whose spectral components are peaked at twice the superconducting gap energy 2Δ. With narrow-band THz pulses, a THz nonlinear signal was identified at the driving frequency Ω and exhibited a resonant enhancement at temperature when Ω=2Δ. General theoretical considerations show that such a resonance can arise only from a disorder-activated paramagnetic coupling between the light and the electronic current. This proves that the nonlinear THz response can access processes distinct from the diamagnetic Raman-like density fluctuations, which are believed to dominate the nonlinear response at optical frequencies in metals. Our numerical simulations reveal that, even for a small amount of disorder, the Ω=2Δ resonance is dominated by the superconducting amplitude mode over the entire investigated disorder range. This is in contrast to other resonances, whose amplitude-mode contribution depends on disorder. Our findings demonstrate the unique ability of THz 2DCS to explore collective excitations inaccessible in other spectroscopies.