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Number of Pages: 2Integrative BiologyGeological Science

The Impact of Unionization on Establishment Closure: A Regression Discontinuity Analysis of Representation Elections

Using data on more than 27,000 establishments (1983-1999) in the United States, this paper produces estimates of the causal effect of unionization of employer closure by exploiting the fact that most employers become 'unionized' as a partial consequence of a secret ballot election among the workers. If employers where unions barely won the election (e.g. by one vote) are ex ante comparable in all other ways to employers where unions barely lost (by one vote), differences in their subsequent outcomes should represent the true impact of union recognition. The regression discontinuity analysis finds little or no union effect on short- and long-run employer survival rates over 1- to 18-year horizons. We thus conclude that evidence of large effects of unions would more likely be found 1) along the within-employer (intensive margin) of employment and/or 2) in analyses of union threat effects.

Economic Impacts of Unionization on Private Sector Employers: 1984-2001

Economic impacts of unionization on employers are difficult to estimate in the absence of large, representative data on establishments with union status information. Estimates are also confounded by selection bias, because unions could organize at highly profitable enterprises that are more likely to grow and pay higher wages. Using multiple establishment-level data sets that represent establishments that faced organizing drives in the U.S. during 1984-1999, this paper uses a regression discontinuity design to estimate the impact of unionization on business survival, employment, output, productivity, and wages. Essentially, outcomes for employers where unions barely won the election (e.g. by one vote) are compared to those where the unions barely lost. The analysis finds small impacts on all outcomes that we examine; estimates for wages are close to zero. The evidence suggests that at least in recent decades the legal mandate that requires the employer to bargain with a certified union has had little economic impact on employers, because unions have been somewhat unsuccessful at securing significant wage gains.

Fluctuation Spectra and Force Generation in Non-equilibrium Systems

Many biological systems are appropriately viewed as passive inclusions immersed in an active bath: from proteins on active membranes to microscopic swimmers confined by boundaries. The non-equilibrium forces exerted by the active bath on the inclusions or boundaries often regulate function, and such forces may also be exploited in artificial active materials. Nonetheless, the general phenomenology of these active forces remains elusive. We show that the fluctuation spectrum of the active medium, the partitioning of energy as a function of wavenumber, controls the phenomenology of force generation. We find that for a narrow, unimodal spectrum, the force exerted by a non-equilibrium system on two embedded walls depends on the width and the position of the peak in the fluctuation spectrum, and oscillates between repulsion and attraction as a function of wall separation. We examine two apparently disparate examples: the Maritime Casimir effect and recent simulations of active Brownian particles. A key implication of our work is that important non-equilibrium interactions are encoded within the fluctuation spectrum. In this sense the noise becomes the signal

Quantum Algorithms for Fermionic Quantum Field Theories

Extending previous work on scalar field theories, we develop a quantum algorithm to compute relativistic scattering amplitudes in fermionic field theories, exemplified by the massive Gross-Neveu model, a theory in two spacetime dimensions with quartic interactions. The algorithm introduces new techniques to meet the additional challenges posed by the characteristics of fermionic fields, and its run time is polynomial in the desired precision and the energy. Thus, it constitutes further progress towards an efficient quantum algorithm for simulating the Standard Model of particle physics.Comment: 29 page

Quantum Algorithms for Quantum Field Theories

Quantum field theory reconciles quantum mechanics and special relativity, and plays a central role in many areas of physics. We develop a quantum algorithm to compute relativistic scattering probabilities in a massive quantum field theory with quartic self-interactions (phi-fourth theory) in spacetime of four and fewer dimensions. Its run time is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. In the strong-coupling and high-precision regimes, our quantum algorithm achieves exponential speedup over the fastest known classical algorithm.Comment: v2: appendix added (15 pages + 25-page appendix

Quantum Computation of Scattering in Scalar Quantum Field Theories

Quantum field theory provides the framework for the most fundamental physical theories to be confirmed experimentally, and has enabled predictions of unprecedented precision. However, calculations of physical observables often require great computational complexity and can generally be performed only when the interaction strength is weak. A full understanding of the foundations and rich consequences of quantum field theory remains an outstanding challenge. We develop a quantum algorithm to compute relativistic scattering amplitudes in massive phi-fourth theory in spacetime of four and fewer dimensions. The algorithm runs in a time that is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. Thus, it offers exponential speedup over existing classical methods at high precision or strong coupling

Event by Event fluctuation in K/pi ratio at RHIC

We present the preliminary results from our analysis of event by event fluctuation in K/pi ratio in Au+Au collision at \sqrt s_{NN} = 200 GeV and at 62.4 GeV using STAR detector at RHIC. Two different methods have been used to extract the strength of dynamical fluctuation and the centrality dependence of that. The results from the study of energy and centrality dependence of the dynamical fluctuation are presented. From the excitation function it is seen that at two RHIC energies the measure of dynamical fluctuation is constant with values very close to that at 12.3 GeV at SPS. The dynamical fluctuation is found to be positive and decreasing with increasing centrality at RHIC. The results are compared with HIJING model calculation with jets. Results from HIJING are found to be very close to data from central collisions whereas it over predicts the data for peripheral events.Comment: 4 pages, 3 figures, for ICPAQGP - 2005 (Recalculated the errors shown in Fig 2 and Table 1