186,046 research outputs found
The rationale for a safe asset and fiscal capacity for the Eurozone. LEQS Paper No. 144/2019 May 2019
The only way to share common liabilities in the Eurozone is to achieve full fiscal and
political union, i.e. unity of liability and control. In the pursuit of that goal, there is a
need to smooth the transition, avoid unnecessary strains to macroeconomic and
financial stability and lighten the burden of stabilisation policies from national
sovereigns and the European Central Bank, while preserving market discipline and
avoiding moral hazard. Both fiscal and monetary policy face constraints linked to the
high legacy debt in some countries and the zero-lower-bound, respectively, and thus
introducing Eurozone ‘safe assets’ and fiscal capacity at the centre would strengthen
the transmission of monetary and fiscal policies. The paper introduces a standard
Mundell-Fleming framework adapted to the features of a closed monetary union, with
a two-country setting comprising a ‘core’ and a ‘periphery’ country, to evaluate the
response of policy and the economy in case of symmetric and asymmetric demand
and supply shocks in the current situation and following the introduction of safe bonds
and fiscal capacity. Under the specified assumptions, it concludes that a safe asset
and fiscal capacity, better if in combination, would remove the doom loop between
banks and sovereigns, reduce the loss in output for both economies and improve the
stabilisation properties of fiscal policy for both countries, and thus is welfare
enhancing
Some comments on a recently derived approximated solution of the Einstein equations for a spinning body with negligible mass
Recently, an approximated solution of the Einstein equations for a rotating
body whose mass effects are negligible with respect to the rotational ones has
been derived by Tartaglia. At first sight, it seems to be interesting because
both external and internal metric tensors have been consistently found,
together an appropriate source tensor; moreover, it may suggest possible
experimental checks since the conditions of validity of the considered metric
are well satisfied at Earth laboratory scales. However, it should be pointed
out that reasonable doubts exist if it is physically meaningful because it is
not clear if the source tensor related to the adopted metric can be realized by
any real extended body. Here we derive the geodesic equations of the metric and
analyze the allowed motions in order to disclose possible unphysical features
which may help in shedding further light on the real nature of such
approximated solution of the Einstein equations.Comment: Latex2e, 17 pages, no tables, 5 figures, minor typos corrected. To
appear in general Relativity and Gravitatio
Orbital effects of Lorentz-violating Standard Model Extension gravitomagnetism around a static body: a sensitivity analysis
We analytically work out the long-term rates of change of the six osculating
Keplerian orbital elements of a test particle acted upon by the
Lorentz-violating gravitomagnetic acceleration due to a static body, as
predicted by the Standard Model Extension (SME). We neither restrict to any
specific spatial orientation for the symmetry-violating vector s nor make a
priori simplifying assumptions concerning the orbital configuration of the
perturbed test particle. Thus, our results are quite general, and can be
applied for sensitivity analyses to a variety of specific astronomical and
astrophysical scenarios. We find that, apart from the semimajor axis a, all the
other orbital elements undergo non-vanishing secular variations. By comparing
our results to the latest determinations of the supplementary advances of the
perihelia of some planets of the solar system we preliminarily obtain s_x =
(0.9 +/- 1.5) 10^-8, s_y = (-4 +/- 6) 10^-9, s_z = (0.3 +/- 1) 10^-9. Bounds
from the terrestrial LAGEOS and LAGEOS II satellites are of the order of s\sim
10^-3-10^-4.Comment: LaTex2e, 9 pages, no figures, 3 tables, 25 references. Typos fixe
Space-time decay of Navier-Stokes flows invariant under rotations
We show that the solutions to the non-stationary Navier-Stokes equations in
, which are left invariant under the action of discrete subgroups
of the orthogonal group decay much faster as or than in the generic case and we compute, for each subgroup, the
precise decay rates in space-time of the velocity field
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