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

Welfare Implications of Regionalism in the GATT

This paper investigates the welfare implications of an existence of a free trade agreement (FTA) and a customs union (CU) within the GATT. Two types of GATT regimes are considered in a completely symmetric world: a pure GATT regime without any type of the regional trade agreements (RTAs), and a modified GATT regime with one of them. The main results are for a range of sufficiently high discount rate, first that free trade and global welfare efficiency can be supported under the pure GATT regime but not under the modified regimes, and second that a country's ranking of the both regimes depends on (1) whether it belongs to an RTA or not and (2) which one of the RTAs it belongs to. The insight of these results are that the regionalism in the GATT may restrict free trade and thus fails to achieve the highest global welfare.Most Favored Nation Clause, Free Trade Agreements, Customs Unions

Welfare Implications of Regionalism in the GATT: The Presence of Foreign Ownership

This paper examines the welfare implications of an existence of free trade agreements (FTAs) and customs unions (CUs) in the GATT system, in the presence of cross-foreign ownership among countries. In particular, two GATT regimes are analyzed: a pure GATT regime without any regional free trade agreements, and modified GATT regime with either an FTA or a CU. This paper argues that, when foreign ownership exists significantly between the countries, no countries in the GATT have an incentive to form a regional trade agreement before they participate in multilateral tariff negotiations.Most Favored Nation Clause, Free Trade Agreements, Customs Unions, Foreign Ownership