Topological-Fermi-Liquid to Quantum-Hall-Liquid Transitions: pp-Band and dd-Band Fermions in a Magnetic Field

We find that in a multi-orbital system with intraorbital and interorbital hopping integrals, the Hall conductance exhibits various topological quantum phase transitions (QPTs) induced by on-site orbital polarization: integer quantum Hall (IQH) plateau transitions, and topological Fermi liquid to IQH transitions. Such topological QPTs are demonstrated in two systems: a $p$-band spinless fermionic system realizable with ultracold atoms in optical lattice, and a $d$-band spinful fermionic system closely related to giant orbital Hall effects in transition metals and their compounds.Comment: 4 pages, 4 figure

Inflation dynamics: a cross-country investigation

We document that "persistent and lagged" inflation (with respect to output) is a world-wide phenomenon in that these short-run inflation dynamics are highly synchronized across countries. In particular, the average cross-country correlation of inflation is significantly and systematically stronger than that of output, while the cross-country correlation of money growth is essentially zero. We investigate whether standard monetary models driven by monetary shocks are consistent with the empirical facts. We find that neither the new Keynesian sticky-price model nor the sticky-information model can fully explain the data. An independent contribution of the paper is to provide a simple solution technique for solving general equilibrium models with sticky information. ; Earlier title: Inflation and money: a puzzleMoney ; Inflation (Finance)

Another look at sticky prices and output persistence

Price rigidity is the key mechanism for propagating business cycles in traditional Keynesian theory. Yet the New Keynesian literature has failed to show that sticky prices by themselves can effectively propagate business cycles in general equilibrium. We show that price rigidity in fact can (by itself) give rise to a strong propagation mechanism of the business cycle in standard New Keynesian models, provided that investment is also subject to a cash-in-advance constraint. In particular, we show that reasonable price stickiness can generate highly persistent, hump-shaped movements in output, investment and employment in response to either monetary or non-monetary shocks, even if investment is only partially cash-in-advance constrained. Hence, whether or not price rigidity is responsible for output persistence (and the business cycle in general) may not be a theoretical question, but an empirical one.Prices ; Business cycles