Envy Freeness in Experimental Fair Division Problems

In the recent experimental literature several social preference models have been suggested that address observed behavior not reducible to the pursuit of self-interest. Inequality aversion is one such model where preferences are distributional. Frequently, envy is suggested as the underlying rationale for inequality aversion. Envy is a central criterion in the theoretical literature on fair division, whose definition (Foley 1967) differs from the more casual use of the word in the experimental literature. We present and discuss results from free-form bargaining experiments on fair division problems where the role of envy in Foley’s sense can be analyzed and compared to social preferences. We find that envy freeness does matter as a secondary criterion.Fairness, Envy Freeness, Social Preferences, Bargaining

Inequality Aversion and Efficiency with Ordinal and Cardinal Social Preferences – An Experimental Study

In this paper, we report on a series of free-form bargaining experiments inwhich two players have to distribute four indivisible goods among themselves. In one treatment, players are informed about the monetary payoffs associated with each bundle of goods; in a second treatment only the ordinal ranking of the bundles is given. We find that in both cases, inequality aversion plays a prominent role. In the ordinal treatment, individuals apparently use the ranks in the respective preference orderings over bundles of goods as a substitute for the unknown monetary value. Allocations that distribute the value (money or ranks, respectively) most equally serve as natural “reference points” forthe bargaining processes. Frequently, such “equal split” allocations are chosen by our subjects even though they are Pareto dominated; but also if they are rejected for that reason they matter in a specific way: whether a Pareto optimal allocation is chosen or not depends on whether or not it is a Pareto improvement relative to the equal split. Interestingly, we find much less Pareto-damaging behavior due to inequality aversion in the ordinal treatment

Distributing Indivisible Goods Fairly: Evidence from a Questionnaire Study

We report the results of a questionnaire study on the fair distribution ofindivisible goods. We collected data from three different subject pools, first- and secondyear students majoring in economics, law students, and advanced economics students with some background knowledge of fairness theories. The purpose of this study is to assess the empirical relevance of various fairness criteria such as inequality aversion, the utilitarian principle of maximizing the sum of individual payoffs, the Rawlsian “maximin” principle of maximizing the payoff of the worst-off individual, and the criterion of envy-freeness (in the sense of Foley, 1967)

Envy Freeness in Experimental Fair Division Problems

Envy is sometimes suggested as an underlying motive in the assessment ofdifferent economic allocations. In the theoretical literature on fair division, following Foley (1967), the term “envy” refers to an intrapersonal comparison of different consumption bundles. By contrast, in its everyday use “envy” involves interpersonal comparisons of well-being. We present and discuss results from free-form bargaining experiments on fair division problems in which inter- and intrapersonal criteria can be distinguished. We find that interpersonal comparisons play the dominant role. The effect of the intrapersonal criterion of envy-freeness is limited to situations in which other fairness criteria are not applicable

Trapping and observing single atoms in the dark

A single atom strongly coupled to a cavity mode is stored by three-dimensional confinement in blue-detuned cavity modes of different longitudinal and transverse order. The vanishing light intensity at the trap center reduces the light shift of all atomic energy levels. This is exploited to detect a single atom by means of a dispersive measurement with 95% confidence in 0.010 ms, limited by the photon-detection efficiency. As the atom switches resonant cavity transmission into cavity reflection, the atom can be detected while scattering about one photon

Momentum diffusion for coupled atom-cavity oscillators

It is shown that the momentum diffusion of free-space laser cooling has a natural correspondence in optical cavities when the internal state of the atom is treated as a harmonic oscillator. We derive a general expression for the momentum diffusion which is valid for most configurations of interest: The atom or the cavity or both can be probed by lasers, with or without the presence of traps inducing local atomic frequency shifts. It is shown that, albeit the (possibly strong) coupling between atom and cavity, it is sufficient for deriving the momentum diffusion to consider that the atom couples to a mean cavity field, which gives a first contribution, and that the cavity mode couples to a mean atomic dipole, giving a second contribution. Both contributions have an intuitive form and present a clear symmetry. The total diffusion is the sum of these two contributions plus the diffusion originating from the fluctuations of the forces due to the coupling to the vacuum modes other than the cavity mode (the so called spontaneous emission term). Examples are given that help to evaluate the heating rates induced by an optical cavity for experiments operating at low atomic saturation. We also point out intriguing situations where the atom is heated although it cannot scatter light.Comment: More information adde

Light force fluctuations in a strongly coupled atom-cavity system

Between mirrors, the density of electromagnetic modes differs from the one in free space. This changes the radiation properties of an atom as well as the light forces acting on an atom. It has profound consequences in the strong-coupling regime of cavity quantum electrodynamics. For a single atom trapped inside the cavity, we investigate the atom-cavity system by scanning the frequency of a probe laser for various atom-cavity detunings. The avoided crossing between atom and cavity resonance is visible in the transmission of the cavity. It is also visible in the loss rate of the atom from the intracavity dipole trap. On the normal-mode resonances, the dominant contribution to the loss rate originates from dipole-force fluctuations which are dramatically enhanced in the cavity. This conclusion is supported by Monte-Carlo simulations

s-wave resonances for the 18F(p, a)15O reaction in novae

The 18F(p,$\alpha$) reaction determines the rate of destruction of 18F in novae. It represents the key nuclear physics uncertainty in modelling the calculated flux of annihilation radiation emitted following the radioactive decay of 18F. The major uncertainties relate to states representing s-wave resonances in the compound system, 19Ne. We report a first study of the 19F(3He, t)19Ne reaction at intermediate energies and forward angles. This reaction has a simple, model-independent, mechanism that we use here to identify states near the proton threshold energy in 19Ne corresponding to $\Delta L=0$ transitions. In particular, we observe a $\Delta L=0$ state at 6.13 MeV which could significantly affect the 18F(p,$\alpha$) astrophysical S-factor at nova burning temperatures