GENUINE CORRELATIONS IN FINITE-SIZE SPIN SYSTEMS

Genuine multipartite correlations in finite-size XY chains are studied as a function of the applied external magnetic field. We find that, for low temperatures, multipartite correlations are sensitive to the parity change in the Hamiltonian ground state, given that they exhibit a minimum every time that the ground state becomes degenerate. This implies that they can be used to detect the factorizing point, that is, the value of the external field such that, in the thermodynamical limit, the ground state becomes the tensor product of single-spin states.

Effective Exchange Rates and the Classical Gold Standard Adjustment

Using a new international dataset of trade-weighed exchange rates, this paper highlights a neglected adjustment mechanism in the classical gold standard literature. Since gold-pegged countries traded extensively with economies operating more flexible monetary regimes and where parity change was a common adjustment device to systemic shocks, we show that such parity adjustments induced worldwide swings in nominal effective exchange rates. These translated into real exchange rate variations to which trade balances responded with an average elasticity of unity and in the direction of restoring external disequilibria. We conclude that some nominal exchange rate flexibility thus present in the pre-1914 system was instrumental to international payments adjustment.