Okun’s law, asymmetries and jobless recoveries in the United States: A Markov-switching approach

This paper offers a new perspective on Markov regime-switching approaches to asymmetries in Okun’s law by modeling the existing approaches as special cases. Prevailing models assume either asymmetry between unemployment and output across regimes or asymmetry within a single regime. Our specification combines both approaches. Our empirical results give an insight into the apparent ‘jobless recovery’ experiences that began in the United States in 1991 and 2001

Business confidence and cyclical turning points: A Markov-Switching approach

Markov regime-switching analysis is used to consider the relationship between business confidence and the probability of turning points in cyclical GDP. We find, in an application to New Zealand, that confidence is related to both the deepness and duration of the business cycle and is asymmetric regarding the probability of the economy remaining in a given regime. Overall, the New Zealand business confidence series is a useful indicator of cyclical turning points

Trialling body-worn video cameras for City of London Police: officer perceptions and justice outcomes

Repor

‘Forget it, Jake. It’s Chinatown’: The policing of Chinese organised crime in the UK

This article outlines the impact and changing nature of Chinese organised crime in the United Kingdom (UK). It reviews the conventional policing approaches to the problem in the UK and in China, and argues they are limited in their scope and could be substantially improved. It suggests this is possible by employing police specialists here and in-country. The evidence for the paper has been collected from interviews with the relevant law enforcement and government personnel in the UK and in China in 2010 and again in 2014–15

Control system design using optimization techniques Final report

Optimization techniques for control of fuel valve systems for air breathing jet engines and 40-60 inlet control problem

Resummation of Nonalternating Divergent Perturbative Expansions

A method for the resummation of nonalternating divergent perturbation series is described. The procedure constitutes a generalization of the Borel-Pad\'{e} method. Of crucial importance is a special integration contour in the complex plane. Nonperturbative imaginary contributions can be inferred from the purely real perturbative coefficients. A connection is drawn from the quantum field theoretic problem of resummation to divergent perturbative expansions in other areas of physics.Comment: 5 pages, LaTeX, 2 tables, 1 figure; discussion of the Carleman criterion added; version to appear in Phys. Rev.

Color Gradients Detected in the HD 15115 Circumstellar Disk

We report HST/NICMOS coronagraphic images of the HD 15115 circumstellar disk at 1.1\micron. We find a similar morphology to that seen in the visible and at H band--an edge-on disk that is asymmetric in surface brightness. Several aspects of the 1.1\micron data are different, highlighting the need for multi-wavelength images of each circumstellar disk. We find a flattening to the western surface brightness profile at 1.1\micron interior to 2\arcsec (90 AU) and a warp in the western half of the disk. We measure the surface brightness profiles of the two disk lobes and create a measure of the dust scattering efficiency between 0.55-1.65\micron at 1\arcsec, 2\arcsec, and 3\arcsec. At 2\arcsec the western lobe has a neutral spectrum up to 1.1\micron and a strong absorption or blue spectrum $>$1.1\micron, while a blue trend is seen in the eastern lobe. At 1\arcsec the disk has a red F110W-H color in both lobes.Comment: 4 pages, 4 figures, emulateapj; accepted to ApJ

Relative multiplexing for minimizing switching in linear-optical quantum computing

Many existing schemes for linear-optical quantum computing (LOQC) depend on multiplexing (MUX), which uses dynamic routing to enable near-deterministic gates and sources to be constructed using heralded, probabilistic primitives. MUXing accounts for the overwhelming majority of active switching demands in current LOQC architectures. In this manuscript, we introduce relative multiplexing (RMUX), a general-purpose optimization which can dramatically reduce the active switching requirements for MUX in LOQC, and thereby reduce hardware complexity and energy consumption, as well as relaxing demands on performance for various photonic components. We discuss the application of RMUX to the generation of entangled states from probabilistic single-photon sources, and argue that an order of magnitude improvement in the rate of generation of Bell states can be achieved. In addition, we apply RMUX to the proposal for percolation of a 3D cluster state in [PRL 115, 020502 (2015)], and we find that RMUX allows a 2.4x increase in loss tolerance for this architecture.Comment: Published version, New Journal of Physics, Volume 19, June 201

Witnessing eigenstates for quantum simulation of Hamiltonian spectra

The efficient calculation of Hamiltonian spectra, a problem often intractable on classical machines, can find application in many fields, from physics to chemistry. Here, we introduce the concept of an "eigenstate witness" and through it provide a new quantum approach which combines variational methods and phase estimation to approximate eigenvalues for both ground and excited states. This protocol is experimentally verified on a programmable silicon quantum photonic chip, a mass-manufacturable platform, which embeds entangled state generation, arbitrary controlled-unitary operations, and projective measurements. Both ground and excited states are experimentally found with fidelities >99%, and their eigenvalues are estimated with 32-bits of precision. We also investigate and discuss the scalability of the approach and study its performance through numerical simulations of more complex Hamiltonians. This result shows promising progress towards quantum chemistry on quantum computers.Comment: 9 pages, 4 figures, plus Supplementary Material [New version with minor typos corrected.