Highly entangled photons from hybrid piezoelectric-semiconductor quantum dot devices

Entanglement resources are key ingredients of future quantum technologies. If they could be efficiently integrated into a semiconductor platform a new generation of devices could be envisioned, whose quantum-mechanical functionalities are controlled via the mature semiconductor technology. Epitaxial quantum dots (QDs) embedded in diodes would embody such ideal quantum devices, but QD structural asymmetries lower dramatically the degree of entanglement of the sources and hamper severely their real exploitation in the foreseen applications. In this work, we overcome this hurdle using strain-tunable optoelectronic devices, where any QD can be tuned for the emission of highly polarization-entangled photons. The electrically-controlled sources violate Bell inequalities without the need of spectral or temporal filtering and they feature the highest degree of entanglement ever reported for QDs, with concurrence as high as 0.75(2). These quantum-devices are at present the most promising candidates for the direct implementation of QD-based entanglement-resources in quantum information science and technology

A global analysis of dark matter signals from 27 dwarf spheroidal galaxies using 11 years of Fermi-LAT observations

We search for a dark matter signal in 11 years of Fermi-LAT gamma-ray data from 27 Milky Way dwarf spheroidal galaxies with spectroscopically measured J-factors. Our analysis includes uncertainties in J-factors and background normalisations and compares results from a Bayesian and a frequentist perspective. We revisit the dwarf spheroidal galaxy Reticulum II, confirming that the purported gamma-ray excess seen in Pass 7 data is much weaker in Pass 8, independently of the statistical approach adopted. We introduce for the first time posterior predictive distributions to quantify the probability of a dark matter detection from another dwarf galaxy given a tentative excess. A global analysis including all 27 dwarfs shows no indication for a signal in nine annihilation channels. We present stringent new Bayesian and frequentist upper limits on the dark matter cross section as a function of dark matter mass. The best-fit dark matter parameters associated with the Galactic Centre excess are excluded by at least 95% confidence level/posterior probability in the frequentist/Bayesian framework in all cases. However, from a Bayesian model comparison perspective, dark matter annihilation within the dwarfs is not strongly disfavoured compared to a background-only model. These results constitute the highest exposure analysis on the most complete sample of dwarfs to date. Posterior samples and likelihood maps from this study are publicly available

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

Patricide and overkill: a review of the literature and case report of a murder with Capgras delusion

Despite being an infrequent crime, parental homicide has been associated with schizophrenia spectrum disorders in adult perpetrators and a history of child abuse and family violence in adolescent perpetrators. Among severe psychiatric disorders there is initial evidence that delusional misidentification might also play a role in parricide. Parricides are often committed with undue violence and may result in overkill. The authors present the case of an adult male affected by schizoaffective disorder and Capgras syndrome who committed patricide. Forensic pathologists classify such cases as overkill by multiple fatal means comprising stabbing, blunt trauma and choking. Accurate crime scene investigations coupled with psychiatric examinations of perpetrator allow reconstruction of the murder stages. This overkill case is discussed in the context of a broad review of the literature

SWEET - User manual (version 2.0)

SWEET (Shallow Water Equations Evolving in Time) is a code for the solution of the 2D de Saint Venant equations, written in their conservative form. The code adopts a Finite Differences scheme to advance in time, with a fractional step procedure. The space discretization is realized through Finite Elements, with a linear representation of the water elevation and a quadratic representation of the unit- width discharge. In this document, the physical model and the numerical schemes used for solving the resulting equations are extensively described. The accuracy of the scheme is verified in different test cases. The sequential algorithm has been ported in the parallel computing framework by using the domain decomposition approach. The Schwarz algorithm has been added to the scheme for preconditioning the iterative solution of the elliptic equation modeling the dynamics of the elevation of the water level. The performance of the parallel code are evaluated on a large size computational test case. The structure of the code is explained by a description of the role of each sub- routine and by a flowchart of the program. The input and output files are described in detail, as they constitute the user interface of the code. Both input and output files have a simple structure, and any effort has been made to simplify the procedure of the input setup for the parallel code, and to manage the output results. The PVM message passing library has been used to perform the communications in the parallel version of SWEET. A short introduction to PVM is added at the end of the present report. The SWEET package is the results of a joint work between CRS4 and Enel - Polo Idraulico e Strutturale. The authors of this document kindly acknowledge the valuable contributions of Vincenzo Pennati, from Enel - Polo Idraulico e Strutturale, and of Luca Formaggia, Alfio Quarteroni and Alan Scheinine, from CRS4. This manual is an extension and revision of the SWEET User Manual Version 1.0, 1996. The author of the former document, as well as of the largest part of the SWEET code, is Davide Ambrosi, currently at Politecnico di Torino. To him, not only our sincere thank is due, but mainly the recognizance that SWEET is and will remain a work of his

Inversion of the exciton built-in dipole moment in In(Ga)As quantum dots via nonlinear piezoelectric effect

We show that anisotropic biaxial stress can be used to tune the built-in dipole moment of excitons confined in In(Ga)As quantum dots up to complete erasure of its magnitude and inversion of its sign. We demonstrate that this phenomenon is due to piezoelectricity. We present a model to calculate the applied stress, taking advantage of the so-called piezotronic effect, which produces significant changes in the current-voltage characteristics of the strained diode-membranes containing the quantum dots. Finally, self-consistent k.p calculations reveal that the experimental findings can be only accounted for by the nonlinear piezoelectric effect, whose importance in quantum dot physics has been theoretically recognized although it has proven difficult to single out experimentally.Comment: 6 pages, 4 figure

CXCR4 pos circulating progenitor cells coexpressing monocytic and endothelial markers correlating with fibrotic clinical features are present in the peripheral blood of patients affected by systemic sclerosis

There is still controversy regarding the role of circulating endothelial and progenitor cells (CECs/CEPs) in the pathogenesis of systemic sclerosis (SSc). Using a sequential Boolean gating strategy based on a 4-color flow cytometric protocol, an increased number of CD31(pos)/CD184(pos)(CXCR4)/CD34(pos)/CD45(pos) and CD31(pos)/CD117(pos) (c-kit-R) /CD34(pos)/ CD45(pos) hematopoietic circulating progenitor cells (HCPCs) was detected in SSc patients compared with healthy subjects. In SSc, no circulating mature and progenitor endothelial cells were observed, while an enhanced generation of erythroid progenitor cells was found to be correlated with the presence of CD117+ HCPCs. The presence of freshly detected CXCR4posHCPC was correlated either to the in vitro cultured spindle-shaped endothelial like cells (SELC) with an endo/myelomonocytic profile or to SDF-1 and VEGF serum level. These data are related to more fibrotic clinical features of the disease, thus supporting a possible role of these cells in fibrosis

Bayesian analysis of Friedmannless cosmologies

Assuming only a homogeneous and isotropic universe and using both the 'Gold' Supernova Type Ia sample of Riess et al. and the results from the Supernova Legacy Survey, we calculate the Bayesian evidence of a range of different parameterizations of the deceleration parameter. We consider both spatially flat and curved models. Our results show that although there is strong evidence in the data for an accelerating universe, there is little evidence that the deceleration parameter varies with redshift.Comment: 7 pages, 3 figure

First record of naturalization of Erechtites hieraciifolius (L.) Raf. ex DC. (Asteraceae) in Italy

The plant species Erechtites hieraciifolius (Asteraceae) is here reported for the first time in Italy as a naturalized neophyte in the Classical Karst. The species was observed in 2023 in post-fire forest areas burnt by wildfires in the summer 2022. The features of findings suggest for a naturalization of the species with putative invasive character. This novel occurrence highlights the need for additional research to better understand its colonization and expansion, suggesting the need of early eradication actions

Fast Estimator of Primordial Non-Gaussianity from Temperature and Polarization Anisotropies in the Cosmic Microwave Background

Measurements of primordial non-Gaussianity ($f_{NL}$) open a new window onto the physics of inflation. We describe a fast cubic (bispectrum) estimator of $f_{NL}$, using a combined analysis of temperature and polarization observations. The speed of our estimator allows us to use a sufficient number of Monte Carlo simulations to characterize its statistical properties in the presence of real world issues such as instrumental effects, partial sky coverage, and foreground contamination. We find that our estimator is optimal, where optimality is defined by saturation of the Cramer Rao bound, if noise is homogeneous. Our estimator is also computationally efficient, scaling as $O(N^{3/2})$ compared to the $O(N^{5/2})$ scaling of the brute force bispectrum calculation for sky maps with $N$ pixels. For Planck this translates into a speed-up by factors of millions, reducing the required computing time from thousands of years to just hours and thus making $f_{NL}$ estimation feasible for future surveys. Our estimator in its current form is optimal if noise is homogeneous. In future work our fast polarized bispectrum estimator should be extended to deal with inhomogeneous noise in an analogous way to how the existing fast temperature estimator was generalized.Comment: Submitted to Ap