The Awakening Chinese Economy: Macro and Terms of Trade Impacts on 10 Major Asia-Pacific Countries

This paper analyzes the impact that terms of trade (TOT) are likely to have on the growth of the People’s Republic of China’s (PRC) neighboring countries. Two scenarios employing a dynamic computable general equilibrium framework are considered: (i) a convergence scenario, where historical trends are projected; and (ii) a baseline scenario, where technological progress in the PRC is placed in line with that of the United States (US). The results show that the PRC’s technological convergence leads to increased world prices for mining products, and lower world prices for manufactures, especially those exported extensively by the PRC. On the whole, however, the effects on the growth and TOT of the PRC’s neighboring countries are relatively small. The modelling framework used in this study explicitly captures the various offsetting effects that dampen the impact on TOT and contribute to the small impact on growth. In addition, the additional capital required to finance the PRC’s growth comes predominantly from domestic savings, placing little pressure on the global supply of capital. Thus, an awakening PRC is unlikely to make a dramatic entrance despite the country’s overall positive impact on the region – although there is nothing to fear, there is also only little to gain.computable general equilibrium; multicountry models; People’s Republic of China; terms of trade

Topological Mott Insulator at Quarter Filling in the Interacting Haldane Model

While the recent advances in topology have led to a classification scheme for electronic bands described by the standard theory of metals, a similar scheme has not emerged for strongly correlated systems such as Mott insulators in which a partially filled band carries no current. By including interactions in the topologically non-trivial Haldane model, we show that a quarter-filled state emerges with a non-zero Chern number provided the interactions are sufficiently large. We establish this result first analytically by solving exactly a model in which interactions are local in momentum space. The exact same results obtain also for the Hubbard interaction, lending credence to the claim that both interactions lie in the same universality class. From the simulations with determinantal quantum Monte Carlo, we find that the spin structure at quarter filling is ferromagnetic for the topologically non-trivial case. Possible experimental realizations in cold-atom and solid state systems are discussed

Failure of Topological Invariants in Strongly Correlated Matter

We show exactly that standard `invariants' advocated to define topology for non-interacting systems deviate strongly from the Hall conductance whenever the excitation spectrum contains zeros of the single-particle Green function, $G$, as in general strongly correlated systems. Namely, we show that if the chemical potential sits atop the valence band, the `invariant' changes without even accessing the conduction band but by simply traversing the band of zeros that might lie between the two bands. Since such a process does not change the many-body ground state, the Hall conductance remains fixed. This disconnect with the Hall conductance arises from the replacement of the Hamiltonian, h(\bb k), with $G^{-1}$ in the current operator, thereby laying plain why perturbative arguments fail

1/4 is the new 1/2: Interaction-induced Unification of Quantum Anomalous and Spin Hall Effects

We introduce interactions into two general models for quantum spin Hall physics. Although the traditional picture is that such physics appears when the two lower spinful bands are occupied, that is, half-filling, we show using determinantal quantum Monte Carlo as well as from an exactly solvable model that in the presence of strong interactions, the quarter-filled state instead exhibits the quantum spin Hall effect at high temperature. A topological Mott insulator is the underlying cause. The peak in the spin susceptibility is consistent with a possible ferromagnetic state at $T=0$. The onset of such magnetism would convert the quantum spin Hall to a quantum anomalous Hall effect. We argue that it is the consistency with the Lieb-Schultz-Mattis theorem\cite{lsm1,lsm2} for interacting systems with an odd number of charges per unit cell that underlies the emergence of the quantum anomalous Hall effect as a low-temperature symmetry-broken phase of the quantum spin Hall effect. While such a symmetry-broken phase typically is accompanied by a gap, we find that the interaction strength must exceed a critical value for the gap to form using quantum Monte Carlo dynamical cluster approximation simulations. Hence, we predict that topology can obtain in a gapless phase but only in the presence of interactions in dispersive bands. These results are applied to recent experiments on moir\'e systems and shown to be consistent with valley-coherent quantum anomalous Hall physics.Comment: Figure 4e,f added as well as a referenc

Unpredictably Trump? Predicting Clicktivist-like Actions on Trump's Facebook Posts During the 2016 U.S. Primary Election

This study aims to identify the factors that might cause a Facebook post to be 'liked' by Facebook users. We analyze all the Facebook posts made by Donald Trump's campaign during the U.S. 2016 primary election. Several possible variables were considered, such as the types of Facebook posts, the use of pronouns and emotions, the inclusion of slogans and hashtags, references made to opponents, as well as candidate mentions on national television. The results of the Ordinary Least Squared (OLS) regression show that the use of highly charged (positive and negative) emotions and personalized posts (first-person singular pronouns) increase likes on the candidate's Facebook page. Visual posts (videos and photos) and the use of past tenses do not have a significant effect on post likes. Television mentions decrease the number of likes. The study offers empirical findings contributing to the growing literature on digitally networked participation and support the development of the emerging notion of the new 'hybrid media' system for political communication. It also raises questions as to the relevance of platforms such as Facebook to the democratic process since Facebook users are not necessarily engaging with the content in an organic, democratic way; but instead might be guided to specific content by the Facebook timeline algorithm

How coordinated link sharing behavior and partisans’ narrative framing fan the spread of COVID-19 misinformation and conspiracy theories

This study examines the presence and role of Coordinated Link Sharing Behavior (CLSB) on Facebook around the “America’s Frontline Doctors” press conference, and the promotion of several unproven conspiracy theories including the false assertion that hydroxychloroquine is a “cure” for COVID-19 by Dr. Stella Immanuel, one of the doctors who took part in the press conference. We collected 7,737 public Facebook posts mentioning Stella Immanuel using CrowdTangle and then applied the specialized program CooRnet to detect CLSB among Facebook public pages, groups and verified profiles. Finally, we used a mixed-method approach consisting of both network and content analysis to examine the nature and scope of the detected CLSB. Our analysis shows how Facebook accounts engaged in CLSB to fuel the spread of misinformation. We identified a coalition of Facebook accounts that engaged in CLSB to promote COVID-19 related misinformation. This coalition included US-based pro-Trump, QAnon, and anti-vaccination accounts. In addition, we identified Facebook accounts that engaged in CLSB in other countries, such as Brazil and France, that primarily promoted hydroxychloroquine, and some accounts in African countries that criticized the government's pandemic response in their countries