Spectroscopy of the Potential Profile in a Ballistic Quantum Constriction

We present a theory for the nonlinear current-voltage characteristics of a ballistic quantum constriction. Nonlinear features first develop because of above-barrier reflection from the potential profile, created by impurities in the vicinity of the constriction. The nonlinearity appears on a small voltage scale and makes it possible to determine distances between impurities as well as the magnitude of the impurity potentials.Comment: 3 pages, 4 figures (availiable upon request), REVTEX, Applied Physics Report 93-5

Imaginary moneys as international units of account

The choice of unit of account in longer term unhedged contracts involving parties from multiple countries influences the size and distribution of currency risk. Contracts currently predominantly use the same unit as means of payment and as unit of account. The relative performance of such single currency units of account are contrasted with basket units of account (“imaginary monies” (Einaudi, 1953)) without associated payments function.