An Even Sterner Review: Introducing Relative Prices into the Discounting Debate

The Stern Review has had a major influence on the policy discussion on climate change. One reason is that the report has raised the estimated cost of unmitigated climate damages by an order of magnitude compared to most earlier estimates, leading to a call for strong and urgent action on climate change. Not surprisingly, severe criticism has been levied against the report by authors who think that these results hinge mainly on the use of a discount rate that is too low. Here we discuss the Ramsey rule for the discount rates and its implications for the economics of climate change. While we find no strong objections to the discounting assumptions adopted in the Stern Review, our main point is that the conclusions reached in the review can be justified on other grounds than by using a low discount rate. We argue that nonmarket damages from climate change are probably underestimated and that future scarcities that will be induced by the changing composition of the economy and climate change should lead to rising relative prices for certain goods and services, raising the estimated damage of climate change and counteracting the effect of discounting. We build our analysis on earlier research (Hoel and Sterner 2007) that has shown that the Ramsey discounting formula is somewhat modified in a two-sector economy with differential growth rates. Most importantly, such a model is characterized by changing relative prices, something that has major implications for a correct valuation of future climate damages. We introduce these results into a slightly modified version of the DICE model (Nordhaus 1994) and find that taking relative prices into account can have as large an effect on economically warranted abatement levels as can a low discount rate.discounting, relative prices, Ramsey, climate damage

Quark resonances and high E_t jets

Possible spin-3/2 quark resonances would have a significant effect on high E_{\mbox{\rm t}} jet production through their contribution to the subprocess $q+{\bar q}\rightarrow g+g$. Such enhancements are compared to a, recently reported, anomaly in inclusive jet production at the CDF detector.Comment: 7 pages set in RevTex with four postscript figures appended- all uuencode

The Energy of n Identical Bosons in a Finite Volume at O(L^{-7})

The volume dependence of the ground-state energy of n identical bosons with short-range interactions in a periodic spatial volume with sides of length L is calculated at order L^{-7} in the large volume expansion. This result will enable a refined determination of the pi^+ pi^+ pi^+ interaction from lattice QCD calculations.Comment: 3 page

Optical phase cloaking of 700-nm light waves in the far field by a three-dimensional carpet cloak

Transformation optics is a design tool that connects geometry of space and propagation of light. Invisibility cloaking is a corresponding benchmark example. Recent experiments at optical frequencies have demonstrated cloaking for the light amplitude ("ray cloaking"). In this Letter, we demonstrate far-field cloaking of the light phase ("wave cloaking") by interferometric microscope-imaging experiments on the previously introduced three-dimensional carpet cloak at 700-nm wavelength and for arbitrary polarization of light

Nonequilibrium dynamical mean-field theory for bosonic lattice models

We develop the nonequilibrium extension of bosonic dynamical mean field theory (BDMFT) and a Nambu real-time strong-coupling perturbative impurity solver. In contrast to Gutzwiller mean-field theory and strong coupling perturbative approaches, nonequilibrium BDMFT captures not only dynamical transitions, but also damping and thermalization effects at finite temperature. We apply the formalism to quenches in the Bose-Hubbard model, starting both from the normal and Bose-condensed phases. Depending on the parameter regime, one observes qualitatively different dynamical properties, such as rapid thermalization, trapping in metastable superfluid or normal states, as well as long-lived or strongly damped amplitude oscillations. We summarize our results in non-equilibrium "phase diagrams" which map out the different dynamical regimes.Comment: 18 pages, 8 figure

Phonon band structures of three-dimensional pentamode metamaterials

Three-dimensional pentamode metamaterials are artificial solids that approximately behave like liquids, which have vanishing shear modulus. Pentamodes have recently become experimental reality. Here, we calculate their phonon band structures for various parameters. Consistent with static continuum mechanics, we find that compression and shear waves exhibit phase velocities that can realistically be different by more than one order of magnitude. Interestingly, we also find frequency intervals with more than two octaves bandwidth in which pure single-mode behavior is obtained. Herein, exclusively compression waves exist due to a complete three-dimensional band gap for shear waves and, hence, no coupling to shear modes is possible. Such single-mode behavior might, e.g., be interesting for transformation-elastodynamics architectures.Comment: 5 figure