Gaussian boson sampling validation via detector binning

Gaussian boson sampling (GBS), a computational problem conjectured to be hard to simulate on a classical machine, has been at the forefront of recent years' experimental and theoretical efforts to demonstrate quantum advantage. The classical intractability of the sampling task makes validating these experiments a challenging and essential undertaking. In this paper, we propose binned-detector probability distributions as a suitable quantity to statistically validate GBS experiments employing photon-number-resolving detectors. We show how to compute such distributions by leveraging their connection with their respective characteristic function. The latter may be efficiently and analytically computed for squeezed input states as well as for relevant classical hypothesis like squashed states. Our scheme encompasses other validation methods based on marginal distributions and correlation functions. Additionally, it can accommodate various sources of noise, such as losses and partial distinguishability, a feature that have received limited attention within the GBS framework so far. We also illustrate how binned-detector probability distributions behave when Haar-averaged over all possible interferometric networks, extending known results for Fock boson sampling

Evidence of the influence of the cationic composition on the anionic affinity of layered double hydroxides

International audienceThe effect of the cationic composition on the anionic affinity is evaluated by studying the reconstruction of the layered double hydroxide structure from mixed oxides obtained by the heat treatment of the Mg4Al2-layered double hydroxides solid solution, in aqueous solutions containing carbonates, sulfates, and nitrates. After synthesis, all the samples present the same c parameter whatever the iron content. After a thermal treatment at moderate temperature, amorphous mixed oxides are obtained from all the samples. The influence of the cationic composition is clearly demonstrated on the anionic affinity as the Mg4Al2-amorphous mixed oxides reconstructs the layered double hydroxide structure with 90 % carbonates and 10 % sulfates whereas the Mg4Fe2-amorphous mixed oxides reconstruct the layered double hydroxide structure with 89 % carbonates, 7 % sulfates, and 4 % nitrates. The nitrate ratio increases as the iron content increases

Programmable multi-photon quantum interference in a single spatial mode

The interference of non-classical states of light enables quantum-enhanced applications reaching from metrology to computation. Most commonly, the polarisation or spatial location of single photons are used as addressable degrees-of-freedom for turning these applications into praxis. However, the scale-up for the processing of a large number of photons of such architectures is very resource demanding due to the rapidily increasing number of components, such as optical elements, photon sources and detectors. Here we demonstrate a resource-efficient architecture for multi-photon processing based on time-bin encoding in a single spatial mode. We employ an efficient quantum dot single-photon source, and a fast programmable time-bin interferometer, to observe the interference of up to 8 photons in 16 modes, all recorded only with one detector--thus considerably reducing the physical overhead previously needed for achieving equivalent tasks. Our results can form the basis for a future universal photonics quantum processor operating in a single spatial mode.Comment: 8 pages, 5 figure

Climate, Ticks and Disease

This book brings together expert opinions from scientists to consider the evidence for climate change and its impacts on ticks and tick-borne infections. It considers what is meant by 'climate change', how effective climate models are in relation to ecosystems, and provides predictions for changes in climate at global, regional and local scales relevant for ticks and tick-borne infections. It examines changes to tick distribution and the evidence that climate change is responsible. The effect of climate on the physiology and behaviour of ticks is stressed, including potentially critical impacts on the tick microbiome. Given that the notoriety of ticks derives from pathogens they transmit, the book considers whether changes in climate affect vector capacity. Ticks transmit a remarkable range of micro- and macro-parasites many of which are pathogens of humans and domesticated animals. The intimacy between a tick-borne agent and a tick vector means that any impacts of climate on a tick vector will impact tick-borne pathogens. Most obviously, such impacts will be apparent as changes in disease incidence and prevalence. The evidence that climate change is affecting diseases caused by tick-borne pathogens is considered, along with the potential to make robust predictions of future events. This book contains: Expert opinions and predictions. Global coverage of trends in ticks and disease. In-depth examination of climate change and tick distribution links.This book is suitable for researchers and students studying zoology, biological sciences, medical entomology, animal health, veterinary medicine, epidemiology, parasitology, and climate change impacts; and for those concerned with public health planning or livestock management where ticks and tick-borne pathogens pose a threat