Iterative source and channel decoding relying on correlation modelling for wireless video transmission

Since joint source-channel decoding (JSCD) is capable of exploiting the residual redundancy in the source signals for improving the attainable error resilience, it has attracted substantial attention. Motivated by the principle of exploiting the source redundancy at the receiver, in this treatise we study the application of iterative source channel decoding (ISCD) aided video communications, where the video signal is modelled by a first-order Markov process. Firstly, we derive reduced-complexity formulas for the first-order Markov modelling (FOMM) aided source decoding. Then we propose a bit-based iterative horizontal vertical scanline model (IHVSM) aided source decoding algorithm, where a horizontal and a vertical source decoder are employed for exchanging their extrinsic information using the iterative decoding philosophy. The iterative IHVSM aided decoder is then employed in a forward error correction (FEC) encoded uncompressed video transmission scenario, where the IHVSM and the FEC decoder exchange softbit-information for performing turbo-like ISCD for the sake of improving the reconstructed video quality. Finally, we benchmark the attainable system performance against a near-lossless H.264/AVC video communication system and the existing FOMM based softbit source decoding scheme, where The financial support of the RC-UK under the auspices of the India-UK Advanced Technology Centre (IU-ATC) and that of the EU under the CONCERTO project as well as that of the European Research Council’s Advanced Fellow Grant is gratefully acknowledged. The softbit decoding is performed by a one-dimensional Markov model aided decoder. Our simulation results show that Eb=N0 improvements in excess of 2.8 dB are attainable by the proposed technique in uncompressed video applications

Pinning quantum phase transition of photons in a hollow-core fiber

We show that a pinning quantum phase transition for photons could be observed in a hollow-core one-dimensional fiber loaded with a cold atomic gas. Utilizing the strong light confinement in the fiber, a range of different strongly correlated polaritonic and photonic states, corresponding to both strong and weak interactions can be created and probed. The key ingredient is the creation of a tunable effective lattice potential acting on the interacting polaritonic gas which is possible by slightly modulating the atomic density. We analyze the relevant phase diagram corresponding to the realizable Bose-Hubbard (weak) and sine-Gordon (strong) interacting regimes and conclude by describing the measurement process. The latter consists of mapping the stationary excitations to propagating light pulses whose correlations can be efficiently probed once they exit the fiber using available optical technologiesComment: 4 pages, 4 figures. Comments welcome

Azimuthal correlation between the (p⃗l,p⃗Xb)(\vec{p}_l,\vec{p}_{X_b}) and (p⃗l,P⃗t)(\vec{p}_l,\vec{P}_t) planes in the semileptonic rest frame decay of a polarized top quark: An O(αs)O(\alpha_s) effect

The azimuthal correlation between the planes formed by the vectors $(\vec{p}_\ell,\vec{p}_{X_b})$ and $(\vec{p}_\ell,\vec{P}_t)$ in the semileptonic rest frame decay of a polarized top quark $t(\uparrow) \to X_b + l^+ + \nu_\ell$ belongs to a class of polarization observables involving the top quark which vanish at the Born term level in the standard model. We determine the next--to--leading order QCD corrections to the afore-mentioned azimuthal correlation and compare the result to the corresponding contribution of a non--standard--model right--chiral quark current.Comment: latex, 12 pages with 2 figures in the text, typos removed,comment and references added, replaced with published versio

Simulating spin-charge separation with light

In this work we show that stationary light-matter excitations generated inside a hollow one-dimensional waveguide filled with atoms, can be made to generate a photonic two-component Lieb Liniger model. We explain how to prepare and drive the atomic system to a strongly interacting regime where spin-charge separation could be possible. We then proceed by explaining how to measure the corresponding effective spin and charge densities and velocities through standard optical methods based in measuring dynamically the emitted photon intensities or by analyzing the photon spectrum. The relevant interactions exhibit the necessary tunability both to generate and efficiently observe spin charge separation with current technology.Comment: 4 pages. Comments welcom

Design of a five-axis ultra-precision micro-milling machine—UltraMill. Part 2: Integrated dynamic modelling, design optimisation and analysis

Using computer models to predict the dynamic performance of ultra-precision machine tools can help manufacturers to substantially reduce the lead time and cost of developing new machines. However, the use of electronic drives on such machines is becoming widespread, the machine dynamic performance depending not only on the mechanical structure and components but also on the control system and electronic drives. Bench-top ultra-precision machine tools are highly desirable for the micro-manufacturing of high-accuracy micro-mechanical components. However, the development is still at the nascent stage and hence lacks standardised guidelines. Part 2 of this two-part paper proposes an integrated approach, which permits analysis and optimisation of the entire machine dynamic performance at the early design stage. Based on the proposed approach, the modelling and simulation process of a novel five-axis bench-top ultra-precision micro-milling machine tool—UltraMill—is presented. The modelling and simulation cover the dynamics of the machine structure, the moving components, the control system and the machining process and are used to predict the entire machine performance of two typical configurations

Bayesian Dose Finding for Combined Drugs with Discrete and Continuous Doses

published_or_final_versio

Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots

The development of scalable sources of non-classical light is fundamental to unlocking thetechnological potential of quantum photonics. Semiconductor quantum dots are emerging asnear-optimal sources of indistinguishable single photons. However, their performance assources of entangled-photon pairs are still modest compared to parametric down converters.Photons emitted from conventional Stranski–Krastanov InGaAs quantum dots have shownnon-optimal levels of entanglement and indistinguishability. For quantum networks, bothcriteria must be met simultaneously. Here, we show that this is possible with a system thathas received limited attention so far: GaAs quantum dots. They can emit triggered polar-ization-entangled photons with high purity (g(2)(0) = 0.002±0.002), high indistinguish-ability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity(0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dotentanglement sources in future quantum technologie