Technology and productivity in historical perspective : introduction

This collection of articles is the result of a workshop organised to consider technology and productivity in historical perspective, drawing in particular on the evolutionary approach. The workshop was organised by the N.W. Posthumus Institute for Economic and Social History, the Netherlands Institute for Advanced Study in the Humanities and Social Sciences (NIAS) and the Groningen Growth and Development Centre. Economic historians with backgrounds in both evolutionary and neoclassical traditions came together in the pleasant surroundings of the NIAS at Wassenaar in May 1999, to re-examine technology and productivity experience in Europe since the Industrial Revolution. An important focus was provided by recent theoretical developments, which have seen the incorporation of many evolutionary ideas into mainstream economics. Until quite recently, there seemed to be little common ground between approaches to technology and growth based on Solow's (1956) neoclassical growth model and Nelson and Winter's (1982) evolutionary, neo-Schumpeterian model. Now, however, the evolutionary approach has entered the mainstream through the work of writers such as Grossman and Helpman (1991) and Aghion and Howitt (1998) on endogenous innovation, and David (1985) and Arthur (1994) on path dependence. This is a particularly welcome development from the perspective of the European Historical Economics Society, the sponsors of the European Review of Economic History, holding out the promise of a genuinely ‘historical economics’

Quantum methods for clock synchronization: Beating the standard quantum limit without entanglement

We introduce methods for clock synchronization that make use of the adiabatic exchange of nondegenerate two-level quantum systems: ticking qubits. Schemes involving the exchange of N independent qubits with frequency $\omega$ give a synchronization accuracy that scales as $(\omega\sqrt{N})^{-1}$, i.e., as the standard quantum limit. We introduce a protocol that makes use of N coherent exchanges of a single qubit at frequency $\omega$, leading to an accuracy that scales as $(\omega N)^{-1}\log N$. This protocol beats the standard quantum limit without the use of entanglement, and we argue that this scaling is the fundamental limit for clock synchronization allowed by quantum mechanics. We analyse the performance of these protocols when used with a lossy channel.Comment: 9 pages, 1 figure, published versio

Bayesian Estimation of the Discrepancy with Misspecified Parametric Models

We study a Bayesian model where we have made specific requests about the parameter values to be estimated. The aim is to find the parameter of a parametric family which minimizes a distance to the data generating density and then to estimate the discrepancy using nonparametric methods. We illustrate how coherent updating can proceed given that the standard Bayesian posterior from an unidentifiable model is inappropriate. Our updating is performed using Markov Chain Monte Carlo methods and in particular a novel method for dealing with intractable normalizing constants is required. Illustrations using synthetic data are provided.European Research Council (ERC) through StG "N-BNP" 306406Regione PiemonteMathematic

RK(∗)R_{K^{(*)}} with leptoquarks and the origin of Yukawa couplings

We construct a model where the Yukawa couplings of the Standard Model (SM) fermions arise from the breaking of a $Z_2$ symmetry and through mixing with a fourth family of vector-like fermions. By adding a scalar leptoquark, which is an electroweak triplet and odd under the $Z_2$ symmetry, we obtain an explanation for $R_{K^{(*)}}$ that is linked to the origin of the Yukawa couplings. The coupling of SM fermions to the leptoquark is mediated by the fourth family fermions, and is predicted to be related to CKM entries and mass ratios of SM fermions.Comment: 17 pages, 2 figures. Version accepted for publication in JHE

The Impact of the Sarbanes-Oxley Act (SOX) on the Cost of Equity Capital of S&P Firms

This study examines the impact of SOX on the cost of equity capital for small and large S&P firms. The provisions of SOX aim to improve internal control systems and reduce information asymmetry by improving corporate governance systems and increasing transparency. Using a fixed-effects regression model, our findings suggest that the cost of equity capital has decreased post-SOX for the overall sample of firms, but more specifically for the small firms, which are usually associated with poor internal control systems and high information asymmetry. Collectively, our results provide evidence that SOX has had a positive impact on firms

An S4×SU(5)S_4 \times SU(5) SUSY GUT of flavour in 6d

We propose a 6d model with a SUSY $SU(5)$ gauge symmetry. After compactification, it explains the origin of the $S_4$ Family Symmetry with CSD3 vacuum alignment, as well as $SU(5)$ breaking with doublet-triplet splitting. The model naturally accounts for all quark and lepton (including neutrino) masses and mixings, incorporating the highly predictive Littlest Seesaw structure. It spontaneously breaks CP symmetry, resulting in successful CP violation in the quark and lepton sectors, while solving the Strong CP problem. It also explains the Baryon Asymmetry of the Universe (BAU) through leptogenesis, with the leptogenesis phase directly linked to the Dirac and Majorana phases.Comment: 23 pages, 6 figures. v3: Version published in JHE