Monetary Neutrality

Prize Lecture to the memory of Alfred Nobel, December 7, 1995.Money neutrality;

Trade and the Diffusion of the Industrial Revolution

A model is proposed to describe the evolution of real GDPs in the world economy that is intended to apply to all open economies. The five parameters of the model are calibrated using the Sachs-Warner definition of openness and time-series and cross-section data on incomes and other variables from the 19th and 20th centuries. The model predicts convergence of income levels and growth rates and has strong but reasonable implications for transition dynamics.

Financial Innovation and the Control of Monetary Aggregates: Some Evidence from Canada

This paper presents an empirical test of the proposition that control of a monetary aggregate will generate a rise in its velocity.The test is carried out utilizing the Canadian experience of controlling Ml growth from 1975:3 to 1982:3. Section One of the paper presents evidence of the instability of the Canadian demand from Ml money since 1975:3. Section Two develops a specific form of the proposition which emphasizes the role of asset substitution between classes of chartered bank deposits. A relative asset demand equation is derived from a wealth maximization model subject to a technological transactions constraint and this equation is estimated from 1961 through 1982.The results lend support to the proposition that central bank control of Ml generated a rise in Ml velocity.

Effciency and Equality in a Simple Model of Unemployment Insurance

This paper describes the efficient allocation of consumption and work effort in an economy in which workers face idiosyncratic employment risk and considerations of moral hazard prevent full insurance. We impose a lower bound on the expected discounted utility that can be assigned to any agent from any date onward, and show, with this feature added, that the efficient unemployment insurance scheme induces an invariant cross sectional distribution of individual entitlements to utility. The paper thus provides a simple prototype model suited to the study of the normative question: what is the tradeoff between equality and efficiency in resource allocation?

Targeted Recovery as an Effective Strategy against Epidemic Spreading

We propose a targeted intervention protocol where recovery is restricted to individuals that have the least number of infected neighbours. Our recovery strategy is highly efficient on any kind of network, since epidemic outbreaks are minimal when compared to the baseline scenario of spontaneous recovery. In the case of spatially embedded networks, we find that an epidemic stays strongly spatially confined with a characteristic length scale undergoing a random walk. We demonstrate numerically and analytically that this dynamics leads to an epidemic spot with a flat surface structure and a radius that grows linearly with the spreading rate.Comment: 6 pages, 5 figure

Money and Interest in a Cash-in-Advance Economy

In this paper we analyze an aggregative general equilibrimi model in which the use of money is motivated by a cash-in-advance constraint, applied to purchases of a subset of consumption goods. The system is subject to both real and monetary shocks, which are economy-wide and observed by all. We develop methods for verifying the existence of, characterizing, and explicitly calculating equilibria. A main result of the analysis is that current money growth affects the current real allocation only insofar as it affects expectations about future money growth, i.e., only through its value as a signal.

One-dimensional p-wave superconductor toy-model for Majorana fermions in multiband semiconductor nanowires

Majorana fermions are particles identical to their antiparticles proposed theoretically in 1937 by Ettore Majorana as real solutions of the Dirac equation. Alexei Kitaev suggested that Majorana particles should emerge in condensed matter systems as zero mode excitations in one-dimensional p-wave superconductors, with possible applications in quantum computation due to their non-abelian statistics. The search for Majorana zero modes in condensed matter systems led to one of the first realistic models based in a semiconductor nanowire with high spin-orbit coupling, induced superconducting s-wave pairing and Zeeman splitting. Soon, it was realized that size-quantization effects should generate subbands in these systems that could even allow the emergence of more than one Majorana mode at each edge, resulting in a zero bias peak on the differential conductance with a different shape from the predicted by simplified theoretical models. In this work, we provide a connection between a finite-size nanowire with two occupied subbands and a 2-band Kitaev chain and discuss the advantage of an one-dimensional model to understand the phenomenology of the system, including the presence of a hidden chiral symmetry and its similarity with a spinfull Kitaev chain under a magnetic field.Comment: 4 pages, 2 figures. IEEE Transactions on Applied Superconductivity accepted versio