Coherent Time Evolution and Boundary Conditions of Two-Photon Quantum Walks

Multi-photon quantum walks in integrated optics are an attractive controlled quantum system, that can mimic less readily accessible quantum systems and exhibit behavior that cannot in general be accurately replicated by classical light without an exponential overhead in resources. The ability to observe time evolution of such systems is important for characterising multi-particle quantum dynamics---notably this includes the effects of boundary conditions for walks in spaces of finite size. Here we demonstrate the coherent evolution of quantum walks of two indistinguishable photons using planar arrays of 21 evanescently coupled waveguides fabricated in silicon oxynitride technology. We compare three time evolutions, that follow closely a model assuming unitary evolution, corresponding to three different lengths of the array---in each case we observe quantum interference features that violate classical predictions. The longest array includes reflecting boundary conditions.Comment: 7 pages,7 figure

Quantum walks of correlated photon pairs in two-dimensional waveguide arrays

We demonstrate quantum walks of correlated photons in a 2D network of directly laser written waveguides coupled in a 'swiss cross' arrangement. The correlated detection events show high-visibility quantum interference and unique composite behaviour: strong correlation and independence of the quantum walkers, between and within the planes of the cross. Violations of a classically defined inequality, for photons injected in the same plane and in orthogonal planes, reveal non-classical behaviour in a non-planar structure.Comment: 5 pages, 5 figure

The nonrelativistic limit of the Majorana equation and its simulation in trapped ions

We analyze the Majorana equation in the limit where the particle is at rest. We show that several counterintuitive features, absent in the rest limit of the Dirac equation, do appear. Among them, Dirac-like positive energy solutions that turn into negative energy ones by free evolution, or nonstandard oscillations and interference between real and imaginary spinor components for complex solutions. We also study the ultrarelativistic limit, showing that the Majorana and Dirac equations mutually converge. Furthermore, we propose a physical implementation in trapped ions.Comment: 7 pages, 1 figure. Proceedings of 18th Central European Workshop on Quantum Optics (CEWQO 2011), Madrid, Spai

High-quality polarization entanglement state preparation and manipulation in standard telecommunication channels

We report a novel and simple approach for generating near-perfect quality polarization entanglement in a fully guided-wave fashion. Both deterministic pair separation into two adjacent telecommunication channels and the paired photons' temporal walk-off compensation are achieved using standard fiber components. Two-photon interference experiments are performed, both for quantitatively demonstrating the relevance of our approach, and for manipulating the produced state between bosonic and fermionic symmetries. The compactness, versatility, and reliability of this configuration makes it a potential candidate for quantum communication applications.Comment: 6 figure

Quantum walks of correlated particles

Quantum walks of correlated particles offer the possibility to study large-scale quantum interference, simulate biological, chemical and physical systems, and a route to universal quantum computation. Here we demonstrate quantum walks of two identical photons in an array of 21 continuously evanescently-coupled waveguides in a SiOxNy chip. We observe quantum correlations, violating a classical limit by 76 standard deviations, and find that they depend critically on the input state of the quantum walk. These results open the way to a powerful approach to quantum walks using correlated particles to encode information in an exponentially larger state space

Matter-wave interferometers using TAAP rings

We present two novel matter-wave Sagnac interferometers based on ring-shaped time-averaged adiabatic potentials (TAAP). For both the atoms are put into a superposition of two different spin states and manipulated independently using elliptically polarized rf-fields. In the first interferometer the atoms are accelerated by spin-state-dependent forces and then travel around the ring in a matter-wave guide. In the second one the atoms are fully trapped during the entire interferometric sequence and are moved around the ring in two spin-state-dependent `buckets'. Corrections to the ideal Sagnac phase are investigated for both cases. We experimentally demonstrate the key atom-optical elements of the interferometer such as the independent manipulation of two different spin states in the ring-shaped potentials under identical experimental conditions

Microwave spectroscopy of radio-frequency-dressed 87Rb

We study the hyper fine spectrum of atoms of 87Rb dressed by a radio-frequency field and present experimental results in three different situations: freely falling atoms, atoms trapped in an optical dipole trap, and atoms in an adiabatic radio-frequency dressed shell trap. In all cases, we observe several resonant sidebands spaced (in frequency) at intervals equal to the dressing frequency, corresponding to transitions enabled by the dressing field. We theoretically explain the main features of the microwave spectrum using a semiclassical model in the low-field limit and the rotating-wave approximation for alkali-metal-like species, in general, and 87Rb atoms, in particular. As a proof of concept, we demonstrate how the spectral signal of a dressed atomic ensemble enables an accurate determination of the dressing configuration and the probing microwave field

The effect of pre-exercise ingestion of corinthian currant on endurance performance and blood redox status

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. The present study investigated the effect of Corinthian currant pre-exercise supplementation on metabolism, performance and blood redox status during, and after prolonged exercise. Eleven healthy participants (21-45y) performed a 90-min constant-intensity (60–70% VO2max) submaximal-trial, plus a time-trial (TT) to exhaustion (95% VO2max) after consuming an isocaloric (1.5g CHO/kg BM) amount of randomly assigned Corinthian currant or glucose-drink, or water (control). Blood was drawn at baseline, pre-exercise, 30min, 60min, 90min of submaximal-trial, post-TT, and 1h post-TT. Post-ingestion blood glucose (GLU) under Corinthian currant was higher compared with water, and similar compared with glucose-drink throughout the study. Respiratory quotient under Corinthian currant was similar with glucose-drink and higher than water throughout the submaximal trial. Accordingly, higher CHO and lower fat oxidation were observed under Corinthian currant compared with water. The TT performance was similar between Corinthian currant, glucose-drink and water. Redox status were similar under all three conditions. Reduced glutathione (GSH) declined while total antioxidant capacity (TAC) and uric acid increased during exercise. GSH and TAC returned to baseline, while uric acid remained increased the following 1h. Corinthian currant, although did not alter exercise-mediated redox status changes and performance, was equally effective to a glucose-drink in maintaining GLU levels during prolonged cycling.Published versio

Hybrid neuromuscular training promotes musculoskeletal adaptations in inactive overweight and obese women: A training-detraining randomized controlled trial

This is the author accepted manuscript. The final version is available from Taylor and Francis via the DOI in this recordThis study investigated the effects of a 10-month high-intensity interval-type neuromuscular training program on musculoskeletal fitness in overweight and obese women. Forty-nine inactive females (36.4±4.4 yrs) were randomly assigned to either a control (N=21), a training (N=14, 10 months) or a training-detraining group (N=14, 5 months training followed by 5 months detraining). Training used progressive loaded fundamental movement patterns with prescribed work-to-rest intervals (1:2, 1:1, 2:1) in a circuit fashion (2-3 rounds). Muscular strength and endurance, flexibility, passive range of motion (PRoM), static balance, functional movement screen (FMS) and bone mass density (BMD) and content (BMC) were measured at pre-, mid-, and post-intervention. Ten months of training induced greater changes than the controls in (i) BMD (+1.9%, p<0.001) and BMC (+1.5%, p=0.023) ii) muscular strength (25%-53%, p=0.001-0.005); iii) muscular endurance (103%-195%, p<0.001); and iv) mobility (flexibility: 40%, p<0.001; PRoM [24%-53%, p=0.001-0.05;]; balance: 175%, p=0.058; FMS: +58%, p<0.001). The response rate to training was exceptionally high (86-100%). Five months of detraining reduced but not abolished training-induced adaptations. These results suggest that a hybrid-type exercise approach integrating endurance-based bodyweight drills with resistance-based alternative modes into a real-world gym setting may promote musculoskeletal fitness in overweight or obese women