Do you mind me paying less? Measuring Other-Regarding Preferences in the Market for Taxis

This is the final version. Available on open access from INFORMS via the DOI in this record.We present a natural field experiment designed to measure other–regarding preferences in the market for taxis. We employed testers of varying ethnicity to take a number of predetermined taxi journeys. In each case we endowed them with only 80% of the expected fare. Testers revealed the amount they could afford to pay to the driver mid–journey and asked for a portion of the journey for free. In a 2×2 between–subject design we vary the length of the journey and whether or not a business card is elicited. We find that (1) the majority of drivers give at least part of the journey for free, (2) giving is proportional to the length of the journey and (3) that 27% of drivers complete the journey. Evidence of out–group negativity against black testers is also reported. In order to link our empirical analysis to behavioural theory we estimate the parameters of a number of utility functions. The data and the structural analysis lend support to the quantitative predictions of experiments that measure other–regarding preferences, and shed further light on how discrimination can manifest itself within our preferences.University of Exete

Integrals of Motion for Critical Dense Polymers and Symplectic Fermions

We consider critical dense polymers ${\cal L}(1,2)$. We obtain for this model the eigenvalues of the local integrals of motion of the underlying Conformal Field Theory by means of Thermodynamic Bethe Ansatz. We give a detailed description of the relation between this model and Symplectic Fermions including the indecomposable structure of the transfer matrix. Integrals of motion are defined directly on the lattice in terms of the Temperley Lieb Algebra and their eigenvalues are obtained and expressed as an infinite sum of the eigenvalues of the continuum integrals of motion. An elegant decomposition of the transfer matrix in terms of a finite number of lattice integrals of motion is obtained thus providing a reason for their introduction.Comment: 53 pages, version accepted for publishing on JSTA

Three-leg correlations in the two component spanning tree on the upper half-plane

We present a detailed asymptotic analysis of correlation functions for the two component spanning tree on the two-dimensional lattice when one component contains three paths connecting vicinities of two fixed lattice sites at large distance $s$ apart. We extend the known result for correlations on the plane to the case of the upper half-plane with closed and open boundary conditions. We found asymptotics of correlations for distance $r$ from the boundary to one of the fixed lattice sites for the cases $r\gg s \gg 1$ and $s \gg r \gg 1$.Comment: 16 pages, 5 figure

On the structure of the scalar mesons f0(975)f_0(975) and a0(980)a_0(980)

We investigate the structure of the scalar mesons $f_0(975)$ and $a_0(980)$ within realistic meson-exchange models of the $\pi\pi$ and $\pi\eta$ interactions. Starting from a modified version of the J\"ulich model for $\pi\pi$ scattering we perform an analysis of the pole structure of the resulting scattering amplitude and find, in contrast to existing models, a somewhat large mass for the $f_0(975)$ ($m_{f_0}=1015$ MeV, $\Gamma_{f_0}=30$ MeV). It is shown that our model provides a description of $J/\psi\rightarrow\phi\pi\pi/\phi KK$ data comparable in quality with those of alternative models. Furthermore, the formalism developed for the $\pi\pi$ system is consistently extended to the $\pi\eta$ interaction leading to a description of the $a_0(980)$ as a dynamically generated threshold effect (which is therefore neither a conventional $q\overline{q}$ state nor a $K\overline{K}$ bound state). Exploring the corresponding pole position the $a_0(980)$ is found to be rather broad ($m_{a_0}=991$ MeV, $\Gamma_{a_0}=202$ MeV). The experimentally observed smaller width results from the influence of the nearby $K\overline{K}$ threshold on this pole.Comment: 25 pages, 15 Postscript figure

Solvable Critical Dense Polymers

A lattice model of critical dense polymers is solved exactly for finite strips. The model is the first member of the principal series of the recently introduced logarithmic minimal models. The key to the solution is a functional equation in the form of an inversion identity satisfied by the commuting double-row transfer matrices. This is established directly in the planar Temperley-Lieb algebra and holds independently of the space of link states on which the transfer matrices act. Different sectors are obtained by acting on link states with s-1 defects where s=1,2,3,... is an extended Kac label. The bulk and boundary free energies and finite-size corrections are obtained from the Euler-Maclaurin formula. The eigenvalues of the transfer matrix are classified by the physical combinatorics of the patterns of zeros in the complex spectral-parameter plane. This yields a selection rule for the physically relevant solutions to the inversion identity and explicit finitized characters for the associated quasi-rational representations. In particular, in the scaling limit, we confirm the central charge c=-2 and conformal weights Delta_s=((2-s)^2-1)/8 for s=1,2,3,.... We also discuss a diagrammatic implementation of fusion and show with examples how indecomposable representations arise. We examine the structure of these representations and present a conjecture for the general fusion rules within our framework.Comment: 35 pages, v2: comments and references adde

Hydrothermal activity lowers trophic diversity in Antarctic sedimented hydrothermal vents

Sedimented hydrothermal vents are those in which hydrothermal fluid vents through sediment and are among the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermally active and off-vent areas of the Bransfield Strait (1050–1647 m depth). Microbial composition, biomass and fatty acid signatures varied widely between and within vent and non-vent sites and provided evidence of diverse metabolic activity. Several species showed diverse feeding strategies and occupied different trophic positions in vent and non-vent areas and stable isotope values of consumers were generally not consistent with feeding structure morphology. Niche area and the diversity of microbial fatty acids reflected trends in species diversity and was lowest at the most hydrothermally active site. Faunal utilisation of chemosynthetic activity was relatively limited but was detected at both vent and non-vent sites as evidenced by carbon and sulphur isotopic signatures, suggesting that the hydrothermal activity can affect trophodynamics over a much wider area than previously thought

Refined conformal spectra in the dimer model

Working with Lieb's transfer matrix for the dimer model, we point out that the full set of dimer configurations may be partitioned into disjoint subsets (sectors) closed under the action of the transfer matrix. These sectors are labelled by an integer or half-integer quantum number we call the variation index. In the continuum scaling limit, each sector gives rise to a representation of the Virasoro algebra. We determine the corresponding conformal partition functions and their finitizations, and observe an intriguing link to the Ramond and Neveu-Schwarz sectors of the critical dense polymer model as described by a conformal field theory with central charge c=-2.Comment: 44 page

Discrimination in a deprived neighbourhood: an artefactual field experiment

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.We present a field experiment designed to examine the discriminatory motives of an understudied demographic: the poorest people in England. Subjects are first asked to divide £10 between two strangers, and then play a £10 dictator game with another stranger. We subtly vary the ethnicity of the receivers by providing subjects with surnames randomly drawn from the electoral register, including treatments that allow us to parse behaviour into either in–group favouritism or out–group negativity, an important behavioural distinction that is typically overlooked in the discrimination literature. Our results suggest that the observed discriminatory attitudes are the result of out-group negativity rather than in-group favouritism. We advance the literature on discrimination through the estimation of a structural model of group– contingent social preferences, which we exploit to perform counterfactual simulations. Our results provide insights into the behaviour of this unique demographic and provide a rationale for why they may support discriminatory policies in their voting behaviour