The Dynamics of Growth and Distribution in a Spatially Heterogeneous World

This paper tries to reconcile growth and geographical economics by dealing directly with capital accumulation through time and space and by seeing growth convergence and spatial agglomeration as jointly generated by dynamic processes displaying pattern formation. It presents a centralized economy in which a Bergson-Samuelson- Millian central planner finds a flow of optimal distributions of consumption, subject to a spatial-temporal capital accumulation budget constraint. The main conclusions are: first, if the behavioral parameters are symmetric, but there is an asymmetric distribution of the capital stock, then the long run asymptotic distribution will be spatially homogeneous; second, if there is homogeneous distribution of the capital stock, but there is an asymmetric shock in any parameter, then the economy will converge towards a spatially heterogeneous asymptotic state; third, spatially heterogeneous asymptotic states will only emerge exogenously, not endogenously; fourth, the spatial propagation mechanism can give birth, when the production function is close to linear, to a Turing instability, which implies that for some parameter values, a conditionally stable spacetime distribution should display spatial pattern formation.Optimal growth and distribution; Spatial growth; Optimal control of partial differential equations; Traveling waves; Fourier transforms; Turing instability.

Fiscal Discipline and Stability under Currency Board Systems

In economic discussions, currency board systems are frequently described as arrangements with self-binding character to the monetary authorities by their strict rules and establishments by law. Hard pegs and especially currency boards are often seen as remedies to overcome economic and financial turmoils and to return to low inflation. A sustainable debt level closely linked to a disciplined fiscal policy is, however, a premise for medium-term success. We show in a two-period model that the choice of a currency board can increase fiscal discipline compared to a standard peg regime. We derive, furthermore, the conditions for a currency boards to gain a stability advantage compared to a common peg system.currency board, fixed exchange rate, commitment, inflation bias, fiscal discipline, public debt, time-inconsistency problem

"Locational Disadvantage and Losses from Trade: Three Regions in Economic Geography"

We show that how spatial evolution is different between the two representative models of economic geography: Krugman (1991 JPE) and Ottaviano et al. (2002 IER). We analyze the impacts of falling transport costs on the spatial distribution of economic activities and welfare for three regions located on a line. In the former model, the central region always has locational advantage and manufacturing workers gain from trade. In the latter model, however, the opposite is true when markets are opened up to trade. This is because the price competition is so keen in the central region that manufacturing sector moves to the peripheral regions, which aggravates the social welfare. We then show that when goods are close substitutes and share of manufacturing is of an intermediate level, the manufacturing activities completely disappears from the central region leading to a full agglomeration in one peripheral region.

On the solitons of the Chern-Simons-Higgs model

Several issues concerning the self-dual solutions of the Chern-Simons-Higgs model are addressed. The topology of the configuration space of the model is analysed when the space manifold is either the plane or an infinite cylinder. We study the local structure of the moduli space of self-dual solitons in the second case by means of an index computation. It is shown how to manage the non-integer contribution to the heat-kernel supertrace due to the non-compactness of the base space. A physical picture of the local coordinates parametrizing the non-topological soliton moduli space arises .Comment: 27 pages, 3 figures, to appear in The European Physical Journal

Implications of ERM2 for Poland’s Monetary Policy

This study proposes an extension to the inflation targeting framework for Poland that takes into consideration the exchange rate stability constraints imposed by the obligatory participation in the ERM2 on the path to the euro. The modified policy framework is based on targeting the differential between the domestic and the implicit euro area inflation forecasts. The exchange rate stability objective enters the central bank reaction function and is treated as an indicator variable. Adjustments of interest rates respond to changes in the relative inflation forecast, while foreign exchange market intervention is applied for the purpose of stabilizing the exchange rate. The dynamic market equilibrium exchange rate is ascertained by employing the Johanssen cointegration tests and the threshold generalized autoregressive heteroscedasticity model with the in-mean extension and generalized error distribution (TGARCH-M-GED).http://deepblue.lib.umich.edu/bitstream/2027.42/40188/3/wp802.pd

Quantum phases and topological properties of interacting fermions in one-dimensional superlattices

The realization of artificial gauge fields in ultracold atomic gases has opened up a path towards experimental studies of topological insulators and, as an ultimate goal, topological quantum matter in many-body systems. As an alternative to the direct implementation of two-dimensional lattice Hamiltonians that host the quantum Hall effect and its variants, topological charge-pumping experiments provide an additional avenue towards studying many-body systems. Here, we consider an interacting two-component gas of fermions realizing a family of one-dimensional superlattice Hamiltonians with onsite interactions and a unit cell of three sites, whose groundstates would be visited in an appropriately defined charge pump. First, we investigate the grandcanonical quantum phase diagram of individual Hamiltonians, focusing on insulating phases. For a certain commensurate filling, there is a sequence of phase transitions from a band insulator to other insulating phases (related to the physics of ionic Hubbard models) for some members of the manifold of Hamiltonians. Second, we compute the Chern numbers for the whole manifold in a many-body formulation and show that, related to the aforementioned quantum phase transitions, a topological transition results in a change of the value and sign of the Chern number. We provide both an intuitive and conceptual explanation and argue that these properties could be observed in quantum-gas experiments