Trade Costs, Conflicts, and Defense Spending

This paper develops a quantitative model of trade, military conflicts, and defense spending. Trade liberalization between two countries reduces probability of an armed conflict between them, causing both to cut defense spending. This in turn causes a domino effect on defense spending by other countries. As a result, both countries and the rest of the world are better off. We estimate the model using data on trade, conflicts, and military spending. We find that, after reduction of costs of trade between a pair of hostile countries, the welfare effect of worldwide defense spending cuts is comparable in magnitude to the direct welfare gains from trade

Constrained Hybrid Monte Carlo algorithms for gauge-Higgs models

We develop Hybrid Monte Carlo (HMC) algorithms for constrained Hamiltonian systems of gauge- Higgs models and introduce a new observable for the constraint effective Higgs potential. We use an extension of the so-called Rattle algorithm to general Hamiltonians for constrained systems, which we adapt to the 4D Abelian-Higgs model and the 5D SU(2) gauge theory on the torus and on the orbifold. The derivative of the potential is measured via the expectation value of the Lagrange multiplier for the constraint condition and allows a much more precise determination of the effective potential than conventional histogram methods. With the new method, we can access the potential over the full domain of the Higgs variable, while the histogram method is restricted to a short region around the expectation value of the Higgs field in unconstrained simulations, and the statistical precision does not deteriorate when the volume is increased. We further verify our results by comparing to the one-loop Higgs potential of the 4D Abelian-Higgs model in unitary gauge and find good agreement. To our knowledge, this is the first time this problem has been addressed for theories with gauge fields. The algorithm can also be used in four dimensions to study finite temperature and density transitions via effective Polyakov loop actions.Comment: added comparison to one-loop potential in section 3.3, improved text; version accepted for publication in Computer Physics Communication

Entwicklungen der Weltwirtschaft im Kontext der Finanzmarktkrise

GERMAN: Die im August 2007 ausgebrochene Finanzkrise erfüllt alle Kriterien einer systemischen Bankenkrise. Zahlungsschwierigkeiten häufen sich, die Kapitalisierung von Banken sinkt und Aktienkurse fallen, während die realen Zinssätze steigen. Ausschlaggebend für diese Entwicklungen ist der Vertrauensverlust zwischen den Banken nach den großen Abschreibungsverlusten, die aus dem Platzen der US-Sub-Prime-Blase resultieren. Staatliche Unterstützungsmaßnahmen in den USA und im Euro-Raum konnten bislang die am Interbankenmarkt entstandene Liquiditätskrise nicht beenden. Aufgrund des hohen Leverage vieler Banken erforderten die Abschreibungsverluste eine Verkürzung der Bankbilanzen. Dieser Deleverage-Prozess zog den Verkauf von Vermögenswerten und eine restriktivere Kreditvergabe mit sich. Die internationale Vernetzung der Banken und Finanzmärkte führte dazu, dass seit September 2008 auch viele Schwellenländer und mittel- und osteuropäischen Länder (MOEL) die Finanzmarktkrise zu spüren bekamen, nachdem ausländische Investoren Kapital aus diesen Märkten abzogen. Dadurch kämpfen mittlerweile mehrere Länder mit der Finanzierung ihres Leistungsbilanzdefizits, Liquiditäts- und Währungskrisen. Die wichtigsten Kanäle für die internationale Krisenausbreitung sind dabei die internationalen Kapitalflüsse und global agierende Banken. Langfristig werden Länder mit großer Exportabhängigkeit von den USA oder dem Euro-Raum auch unter der konjunkturbedingt schwachen Nachfrage leiden. Der aufgrund der schlechten Konjunkturaussichten seit Mitte 2008 sinkende Ölpreis wird den Abbau der bestehenden externen Ungleichgewichte beschleunigen. Dazu beitragen könnte auch eine relative Verschiebung der Bedeutung von Export und Inlandsnachfrage in den Wachstumsprozessen der USA und China, während die jüngsten Wechselkursentwicklungen einem Equilibrierungsprozess entgegen laufen. Das große Wachstumsdifferential zwischen den Industrieländern und den großen Schwellenländern dürfte bis 2009 bestehen bleiben oder sich sogar ausweiten. 2009 werden die großen Schwellenländer China, Indien, Brasilien sowie Russland den überwiegenden Teil zum Wachstum der Weltwirtschaft beitragen, während der Beitrag der USA, der EU und Japans rezessionsbedingt negativ sein wird. ---- ENGLISH: Developments in the world economy in the context of the financial crisis The financial crisis that erupted in August 2007 has developed into a dramatic systemic banking crisis: the number of defaults in the banking and corporate sector increased, asset prices declined depressing the capitalisation of banks, while real interest rates increased. A major force driving this development is the loss of confidence among banks following the huge write-downs in the wake of securitization and the burst of the US-sub prime bubble. State interventions in the US and the Euro area were unable to resolve the liquidity crisis on the inter-bank market. Due to the high leverage of many banks, the incurred losses required a shortening of banks' balance sheets. The de-leveraging process implied the sale of assets and a more restrictive lending policy by banks. By September 2008 international linkages between banks and financial markets caused the financial market crisis to spread to many emerging markets and also the Central and Eastern European Countries (CEEC) as foreign investors withdrew capital from these markets. Since then many CEEC have struggled with the financing of their current account deficits, with liquidity and currency crises. Countries with strong export dependency on the US or the Euro-area started to suffer from weakened demand. Developments with regard the previously built-up large global external equilibria moved in different directions: The move into recession of many consuming countries since mid-2008 caused oil prices (and other commodity prices) to recede. This contributes towards a reduction in existing external imbalances. The sharp fall in domestic demand in the US economy is another contributing factor, whereas the latest exchange rate development (appreciating dollar) acts as a counterbalancing force in this equilibrating process. Growth differentials between industrialised countries and some of the major emerging markets mean that in 2009 in spite of the general global slow-down, it will only be the major emerging markets such as China and India which will contribute positively to the growth of the world economy, whereas the US, the EU and Japan will all make negative contributions.transitional economies, comparative study, economic growth, fiscal and monetary policy, macroeconomic forecast, macroeconomic analysis