Kondo Resonance of a Microwave Photon

We emulate renormalization group models, such as the Spin-Boson Hamiltonian or the anisotropic Kondo model, from a quantum optics perspective by considering a superconducting device. The infra-red confinement involves photon excitations of two tunable transmission lines entangled to an artificial spin-1/2 particle or double-island charge qubit. Focusing on the propagation of microwave light, in the underdamped regime of the Spin-Boson model, we identify a many-body resonance where a photon is absorbed at the renormalized qubit frequency and reemitted forward in an elastic manner. We also show that asymptotic freedom of microwave light is reached by increasing the input signal amplitude at low temperatures which allows the disappearance of the transmission peak.Comment: Final Version: Main text and Supplementary Materia

On the Role of Local Content Requirement in Defusing the Threat of Quid-Pro-Quo FDI

We analyze local content requirement (LCR) and tariff in a two-country model of vertical market-structure with endogenous foreign direct investment (FDI). The foreign firm chooses whether to export or to undertake FDI. The host country anticipates the potential for FDI and selects tariff with or without LCR rate accordingly. Without LCR, the FDI imposes a threat on the host country and the threat exerts a tariff-liberalizing pressure. This FDI is often coined as quid-pro-quo FDI in the literature. In contrast, we show that with LCR the host government can defuse the threat of quid-pro-quo FDItariff, local content requirement, export, quid-pro-quo foreign direct investment

A Note on Free Trade Agreement and Wage Bargaining Structure

Mezzeti and Dinopoulos (1991) show that a free trade agreement (trade liberalization) decreases wage rate. However, Naylor (1998) shows that trade liberalization increases wage rate. Both papers consider tariff as exogenously given. In this paper we show that these conflicting results can be nested into a model of international duopoly with a more general wage bargaining structure. Tariff is endogenously determined in our model. In addition, we also derive crucial implications of the wage bargaining structure on the sustainability of trade liberalizationwage bargaining structure, optimal tariff regime, free trade agreement

Organizational Structure and Product Market Competition

We analyze an interaction between a firm’s choice of organizational structure and competition in the product-market. Two organizational structures are considered, namely a centralized-organization, whereby formal authority is retained by a principal, and a decentralized-organization, whereby formal authority is delegated to an agent. We show that the choice of organizational structure hinges on a trade-off between operating-profit and managerial effort. The principal may prefer to choose an organizational structure that generates lower operating-profit to motivate the agent to work hard. The choice of organizational structure may also determine whether the rival is active in the market or forced to exit the market.Formal and Real Authority, Delegation Structure, Product Market Competition

Collaborative consumption for small and medium-sized fashion enterprises in South Korea

Sustainability in the fashion industry is challenging due to numerous problems, which entail both complex production and consumption processes in a global context. Over the past decade, clothing consumption patterns have changed considerably, influenced by the disposable fast fashion phenomenon. In recent decades, the need to incorporate sustainability in business practices in the fashion industry has become increasingly clear. The concept of a “circular economy” (CE) has been promoted to highlight the need to find an alternative approach for recovering or regenerating resources for the maximum value of a garment’s life (WRAP 2016) . This concept has attracted increasing attention because of the need to reduce waste and optimize resource productivity while achieving a competitive advantage and reducing the negative environmental effects of clothing production and consumption (WRAP 2016)

2δ2\delta-Kicked Quantum Rotors: Localization and `Critical' Statistics

The quantum dynamics of atoms subjected to pairs of closely-spaced $\delta$-kicks from optical potentials are shown to be quite different from the well-known paradigm of quantum chaos, the singly-$\delta$-kicked system. We find the unitary matrix has a new oscillating band structure corresponding to a cellular structure of phase-space and observe a spectral signature of a localization-delocalization transition from one cell to several. We find that the eigenstates have localization lengths which scale with a fractional power $L \sim \hbar^{-.75}$ and obtain a regime of near-linear spectral variances which approximate the `critical statistics' relation $\Sigma_2(L) \simeq \chi L \approx {1/2}(1-\nu) L$, where $\nu \approx 0.75$ is related to the fractal classical phase-space structure. The origin of the $\nu \approx 0.75$ exponent is analyzed.Comment: 4 pages, 3 fig

Cross-Border M&A Inflows and the Quality of Institutions: A Cross-Country Panel Data Analysis

This paper provides an empirical explanation to the observed disparity in cross-border M&A inflows to developing and developed countries over the last two decades. We show two main results. First, the disparity can be attributed to the difference in the quality of institutions between the two groups of countries. Second, the gain from reforming institutions in developing countries is smaller than that in developed countries. These findings suggest that, with the current speed of institutional reforms in developing countries, the disparity is likely to persist.cross-border M&A inflows, quality of institutions, developing and developed countries, pooled-data and panel data analysis, correlated random effects

Near zero modes in condensate phases of the Dirac theory on the honeycomb lattice

We investigate a number of fermionic condensate phases on the honeycomb lattice, to determine whether topological defects (vortices and edges) in these phases can support bound states with zero energy. We argue that topological zero modes bound to vortices and at edges are not only connected, but should in fact be \emph{identified}. Recently, it has been shown that the simplest s-wave superconducting state for the Dirac fermion approximation of the honeycomb lattice at precisely half filling, supports zero modes inside the cores of vortices (P. Ghaemi and F. Wilczek, 2007). We find that within the continuum Dirac theory the zero modes are not unique neither to this phase, nor to half filling. In addition, we find the \emph{exact} wavefunctions for vortex bound zero modes, as well as the complete edge state spectrum of the phases we discuss. The zero modes in all the phases we examine have even-numbered degeneracy, and as such pairs of any Majorana modes are simply equivalent to one ordinary fermion. As a result, contrary to bound state zero modes in $p_x+i p_y$ superconductors, vortices here do \emph{not} exhibit non-Abelian exchange statistics. The zero modes in the pure Dirac theory are seemingly topologically protected by the effective low energy symmetry of the theory, yet on the original honeycomb lattice model these zero modes are split, by explicit breaking of the effective low energy symmetry.Comment: Final version including numerics, accepted for publication in PR

A Supersymmetric U(1)' Model with Multiple Dark Matters

We consider a scenario where a supersymmetric model has multiple dark matter particles. Adding a U(1)' gauge symmetry is a well-motivated extension of the Minimal Supersymmetric Standard Model (MSSM). It can cure the problems of the MSSM such as the mu-problem or the proton decay problem with high-dimensional lepton number and baryon number violating operators which R-parity allows. An extra parity (U-parity) may arise as a residual discrete symmetry after U(1)' gauge symmetry is spontaneously broken. The Lightest U-parity Particle (LUP) is stable under the new parity becoming a new dark matter candidate. Up to three massive particles can be stable in the presence of the R-parity and the U-parity. We numerically illustrate that multiple stable particles in our model can satisfy both constraints from the relic density and the direct detection, thus providing a specific scenario where a supersymmetric model has well-motivated multiple dark matters consistent with experimental constraints. The scenario provides new possibilities in the present and upcoming dark matter searches in the direct detection and collider experiments.Comment: 25 pages, 5 figure

Chaotic quantum ratchets and filters with cold atoms in optical lattices: properties of Floquet states

Recently, cesium atoms in optical lattices subjected to cycles of unequally-spaced pulses have been found to show interesting behavior: they represent the first experimental demonstration of a Hamiltonian ratchet mechanism, and they show strong variability of the Dynamical Localization lengths as a function of initial momentum. The behavior differs qualitatively from corresponding atomic systems pulsed with equal periods, which are a textbook implementation of a well-studied quantum chaos paradigm, the quantum delta-kicked particle (delta-QKP). We investigate here the properties of the corresponding eigenstates (Floquet states) in the parameter regime of the new experiments and compare them with those of the eigenstates of the delta-QKP at similar kicking strengths. We show that, with the properties of the Floquet states, we can shed light on the form of the observed ratchet current as well as variations in the Dynamical Localization length.Comment: 9 pages, 9 figure