Is the σ\sigma meson dynamically generated?

We study the problem whether the $\sigma$ meson is generated `dynamically'. A pedagogical analysis on the toy O(N) linear sigma model is performed and we find that the large $N_c$ limit and the $m_\sigma\to \infty$ limit does not commute. The sigma meson may not necessarily be described as a dynamically generated resonance. On the contrary, the sigma meson may be more appropriately described by considering it as an explicit degree of freedom in the effective lagrangian.Comment: Contribution to ``Quark Confinement and Hadron Spectrum VII'', 2--7 Sept. 2006, Ponta Delgada, Acores, Portuga

Quantum Information Approach to Bose-Einstein Condensate in a Tilted Double-Well System

We study the ground state properties of bosons in a tilted double-well system. We use fidelity susceptibility to identify the possible ground state transitions under different tilt values. For a very small tilt (for example $10^{-10}$), two transitions are found. For a moderate tilt (for example $10^{-3}$), only one transition is found. For a large tilt (for example $10^{-1}$), no transition is found. We explain this by analyzing the spectrum of the ground state. The quantum discord and total correlation of the ground state under different tilts are also calculated to indicate those transitions. In the transition region, both quantities have peaks decaying exponentially with particle number $N$. This means for a finite-size system the transition region cannot be explained by the mean-field theory, but in the large-$N$ limit it can be.Comment: 5 pages, 5 figures, slightly different from the published versio

Analysis of synaptic weight distribution in an Izhikevich network

Izhikevich network is a relatively new neuronal network, which consists of cortical spiking model neurons with axonal conduction delays and spike-timingdependent plasticity (STDP) with hard bound adaptation. In this work, we use uniform and Gaussian distributions respectively to initialize the weights of all excitatory neurons. After the network undergoes a few minutes of STDP adaptation, we can see that the weights of all synapses in the network, for both initial weight distributions, form a bimodal distribution, and numerically the established distribution presents dynamic stability

Wolf Warrior Spreads Superior: The narrative and effectiveness of Chinese public diplomacy behaviours on Twitter

Since 2013, when President Xi Jinping pioneered the concept of "telling China's stories well," the number of senior Chinese diplomats and state-affiliated media accounts on Twitter has increased. Different from the vague and evasive diplomatic parlance, some diplomats defend the policies of China in a relatively aggressive way, even sometimes resulting in online disputes with foreign politicians. They are labeled as "wolf-warrior diplomats," a term coined from the record-breaking Chinese nationalist action movie series Wolf Warrior. This paper investigates the effectiveness of China's "wolf warrior diplomacy" on audience engagement on Twitter and significant factors impacting communication effectiveness. Through the utilization of advanced offensive and humor detection algorithms, counterintuitively, this study finds that the wolf-warrior tweets improve Twitter audience engagement, though prior research pointed out that these tweets may bring out adverse feelings in some audiences. Moreover, it also unveils that providing more information and posting humorously on Chinese diplomatic Tweets can enhance their reach and dissemination