Back and Forth: Reverse Phase Transitions in Numerical Relativity Simulations

Multi-messenger observations of binary neutron star mergers provide a uniqueopportunity to constrain the dense-matter equation of state. Although it isknown from quantum chromodynamics that hadronic matter will undergo a phasetransition to exotic forms of matter, e.g., quark matter, the onset density ofsuch a phase transition cannot be computed from first principles. Hence, itremains an open question if such phase transitions occur inside isolatedneutron stars or during binary neutron star mergers, or if they appear at evenhigher densities that are not realized in the Cosmos. In this article, weperform numerical-relativity simulations of neutron-star mergers andinvestigate scenarios in which the onset density of such a phase transition isexceeded in at least one inspiralling binary component. Our simulations revealthat shortly before the merger it is possible that such stars undergo a"reverse phase transition", i.e., densities decrease and the quark core insidethe star disappears leaving a purely hadronic star at merger. After the merger,when densities increase once more, the phase transition occurs again and leads,in the cases considered in this work, to a rapid formation of a black hole. Wecompute the gravitational-wave signal and the mass ejection for our simulationsof such scenarios and find clear signatures that are related to the postmergerphase transition, e.g., smaller ejecta masses due to the softening of theequation of state through the quark core formation. Unfortunately, we do notfind measurable imprints of the reverse phase transition.<br

Visualization of wave function of quantum dot at fermi-edge singularity regime

We consider electron tunneling spectroscopy through an InAs quantum dot in a magnetic field applied perpendicular to the tunneling direction. We examine in details the anisotropic behavior of the amplitude and shape of the resonant peaks of I-V curves and concluded that (i) magnetotunneling spectroscopy at FES regime allows establishing position of resonant level in QD with high accuracy. (ii) The distinguishable shape of FES peak allows extracting the amplitude with much better accuracy. (iii) FES exponent dependence on magnetic field gives additional information about potential distribution outside QD.Foundation for Science and Technology (FCT

Cyclotron enhancement of tunneling

A state of an electron in a quantum wire or a thin film becomes metastable, when a static electric field is applied perpendicular to the wire direction or the film surface. The state decays via tunneling through the created potential barrier. An additionally applied magnetic field, perpendicular to the electric field, can increase the tunneling decay rate for many orders of magnitude. This happens, when the state in the wire or the film has a velocity perpendicular to the magnetic field. According to the cyclotron effect, the velocity rotates under the barrier and becomes more aligned with the direction of tunneling. This mechanism can be called cyclotron enhancement of tunneling

Distillation End Point Estimation in Diesel Fuel Production

Soft sensors for the on-line estimation of kerosene 95 % distillation end point (D95) in crude distillation unit (CDU) are developed. Experimental data are acquired from the refinery distributed control system (DCS) and include on-line available continuously measured variables and laboratory data which are consistently sampled four times a day. Additional laboratory data of kerosene D95 for the model identification are generated by Multivariate Adaptive Regression Splines (MARSplines). Soft sensors are developed using different linear and nonlinear identification methods. Among the variety of dynamic models, the best results are achieved with Box Jenkins (BJ), Output Error (OE) and Hammerstein–Wiener (HW) model. Developed models were evaluated based on the Final Prediction Error (FPE), Root Mean Square Error (RMSE), mean Absolute Error (AE) and FIT coefficients. The best results for diagnostic purposes show BJ model. For continuous estimation of D95, OE and HW models can be used