Phase diagram of a 2D Ising model within a nonextensive approach

In this work we report Monte Carlo simulations of a 2D Ising model, in which the statistics of the Metropolis algorithm is replaced by the nonextensive one. We compute the magnetization and show that phase transitions are present for $q\neq 1$. A $q -$ phase diagram (critical temperature vs. the entropic parameter $q$) is built and exhibits some interesting features, such as phases which are governed by the value of the entropic index $q$. It is shown that such phases favors some energy levels of magnetization states. It is also showed that the contribution of the Tsallis cutoff is essential to the existence of phase transitions

Understanding the Greenspan standard

Greenspan, Alan ; Monetary policy ; Business cycles ; Economic conditions

Understanding the Greenspan Standard

Alan Greenspan was sworn in as Chairman of the Board of Governors of the Federal Reserve System almost exactly 18 years ago. At the time, the Reagan administration was being rocked by the Iran-contra scandal. The Berlin Wall was standing tall while, in the Soviet Union, Mikhail Gorbachev had just presented proposals for perestroika. The stock market had not crashed since 1929 and, probably by coincidence, Prozac had just been released on the market. The New York Mets, having won the 1986 World Series, were the reigning champions of major league baseball. A lot can change in 18 years.