Optimal Persistent Currents for Interacting Bosons on a Ring with a Gauge Field

We study persistent currents for interacting one-dimensional bosons on a tight ring trap, subjected to a rotating barrier potential, which induces an artificial U(1) gauge field. We show that, at intermediate interactions, the persistent current response is maximal, due to a subtle interplay of effects due to the barrier, the interaction and quantum fluctuations. These results are relevant for ongoing experiments with ultracold atomic gases on mesoscopic rings.Comment: 5 pages + supplemental material, 6 figure

El mecanismo de transmisión de la política monetaria en un entorno de dolarización financiera: El caso del Perú entre 1996 y 2006

El presente estudio analiza los cambios en el mecanismo de transmisión de la política monetaria en el Perú. Una conclusión resaltante que surge a partir de esta investigación es que tanto el canal directo de la tasa de interés como el canal de expectativas han adquirido mayor importancia en los últimos años, especialmente desde que se adoptó el esquema de Metas Explícitas de Inflación. La investigación explora asimismo las implicancias de la dolarización financiera para la práctica de la política monetaria, realizando dos ejercicios con este propósito. En primer lugar, se comparan distintos niveles de flexibilidad del tipo de cambio, observándose que a medida que éste es más flexible, el traspaso del tipo de cambio a precios se hace más rápido pero a la vez se debilita. En segundo lugar, ya que la dolarización financiera generalmente supone depreciaciones contractivas, se estudian las implicancias tanto de las depreciaciones expansivas como de las contractivas. La conclusión es que la efectividad de la política monetaria puede mejorarse aun más si la economía está menos dolarizada.

The monetary policy transmission mechanism under financial dollarization: the case of Peru 1996-2006

This paper analyzes the changes in the monetary policy transmission mechanism in Peru. A strong conclusion that emerges from this research is that both, the direct interest rate channel and the expectations channel have become more important in the recent years, especially after the Inflation Targeting adoption. The research further explores the implications of financial dollarization for the practice of monetary policy by performing two exercises. First, it compares different degrees of exchange rate flexibility and finds out that the more flexible the exchange rate is, the quicker but weaker the exchange rate pass-through becomes. Second, since financial dollarization may trigger contractionary depreciations, the document studies implications for monetary policy. The conclusion is that the effectiveness of monetary policy can be further improved if the economy becomes less dollarized.Transmission Channels, Financial dollarization, Monetary Policy, Emerging Markets.

The XYZ chain with Dzyaloshinsky-Moriya interactions: from spin-orbit-coupled lattice bosons to interacting Kitaev chains

Using the density-matrix renormalization-group algorithm (DMRG) and a finite-size scaling analysis, we study the properties of the one-dimensional completely-anisotropic spin-1/2 XYZ model with Dzyaloshinsky-Moriya (DM) interactions. The model shows a rich phase diagram: depending on the value of the coupling constants, the system can display different kinds of ferromagnetic order and Luttinger-liquid behavior. Transitions from ferromagnetic to Luttinger-liquid phases are first order. We thoroughly discuss the transition between different ferromagnetic phases, which, in the absence of DM interactions, belongs to the XX universality class. We provide evidence that the DM exchange term turns out to split this critical line into two separated Ising-like transitions and that in between a disordered phase may appear. Our study sheds light on the general problem of strongly-interacting spin-orbit-coupled bosonic gases trapped in an optical lattice and can be used to characterize the topological properties of superconducting nanowires in the presence of an imposed supercurrent and of interactions.Comment: 18 pages, 8 figure

Quantum Breathing of an Impurity in a One-dimensional Bath of Interacting Bosons

By means of time-dependent density-matrix renormalization-group (TDMRG) we are able to follow the real-time dynamics of a single impurity embedded in a one-dimensional bath of interacting bosons. We focus on the impurity breathing mode, which is found to be well-described by a single oscillation frequency and a damping rate. If the impurity is very weakly coupled to the bath, a Luttinger-liquid description is valid and the impurity suffers an Abraham-Lorentz radiation-reaction friction. For a large portion of the explored parameter space, the TDMRG results fall well beyond the Luttinger-liquid paradigm.Comment: 10 pages, 7 figures, main text and supplementary material merged in a single PRB style documen

Non Contra sed Supra. The Order of Laws in the Thought of Bonaventura of Bagnoregio

The article aims to formulate a first hypothesis relating to the relationships between the different types of law present in the thought of Bonaventura da Bagnoregio; the reconstruction will take place starting from the bottom, starting from the lex politica, to go back, only in the conclusions, to the lex aeterna, in its double function of foundation and order. The article does not aim to be exhaustive, rather it presents itself as the first step of an investigation that requires other and much more significant levels of in-depth analysis.L’articolo si propone di formulare una prima ipotesi relativa ai rapporti fra i diversi tipi di legge presenti nel pensiero di Bonaventura da Bagnoregio; la ricostruzione avverrà a partire dal basso, prendendo le mosse dalla lex politica, per risalire, solo nelle conclusioni, alla lex aeterna, nella sua doppia funzione di fondamento e ordine. L’articolo non si propone alcun obiettivo di esaustività, si presenta piuttosto come il primo passo di un’indagine che ha bisogno di altri e ben più significativi livelli di approfondimento.   The article aims to formulate a first hypothesis relating to the relationships between the different types of law present in the thought of Bonaventura da Bagnoregio; the reconstruction will take place starting from the bottom, starting from the lex politica, to go back, only in the conclusions, to the lex aeterna, in its double function of foundation and order. The article does not aim to be exhaustive, rather it presents itself as the first step of an investigation that requires other and much more significant levels of in-depth analysis