Precise measurements of the X-ray attenuation coefficient of crystalline silicon have been made in the energy range 25 to 50 keV. The results are compared with theoretical predictions and earlier measurements. A systematic discrepancy between theory and experiment is observed. The most likely cause of the disagreement is thought to be the uncertainty in the estimation of the thermal diffuse scattering cross section.

Generation of nonclassical light suitable for interaction with atoms corresponds to a crucial goal pursued across the broad quantum optics community. We present the generation of nonclassical photon pairs using the process of spontaneous four-wave mixing in warm atomic vapor with an unprecedentedly high degree of nonclassical photon correlations. We show how the unique combination of excitation of atoms in the proximity of the vapor cell viewport, single excitation laser beam, double-Λ energy level scheme, auxiliary optical pumping, and particular optical filtering setups, allow for the spectral bandwidth of generated nonclassical light fields of up to 560 ± 20 MHz and low two-photon noise. We provide a quantitative analysis of particular noise mechanisms which set technological and fundamental limits on the observable photon correlations. The overall technological simplicity of the presented scheme together with the availability of spectrally matched quantum memories implementable with warm atomic vapors promises the feasibility of realization of GHz bandwidth on-demand nonclassical light sources and efficient quantum communication nodes.

We present the experimental generation of light with directly observable close-to-ideal thermal statistical properties. The thermal light state is prepared using a spontaneous Raman emission in a warm atomic vapor. The photon number statistics are evaluated by both the measurement of secondorder correlation function and by the detailed analysis of the corresponding photon number distribution, which certifies the quality of the Bose-Einstein statistics generated by a natural physical mechanism. We further demonstrate the extension of the spectral bandwidth of the generated light to hundreds of MHz domain while keeping the ideal thermal statistics, which suggests a direct applicability of the presented source in a broad range of applications including optical metrology, tests of robustness of quantum communication protocols, or quantum thermodynamics.

We propose and experimentally demonstrate a device for generating light with arbitrary classical photon-number distribution. We use programmable acousto-optical modulation to control the intensity of light within the dynamic range of more than 30 dB and inter-level transitions faster than 500 ns. We propose a universal method that allows the high-fidelity generation of user-defined photon statistics. Extremely high precision <0.001 can be reached for lower photon numbers, and faithful tail behavior can be reached for very high photon numbers. We demonstrate arbitrary statistics generation for up to 500 photons. The proposed device can produce any classical light statistics with given parameters including Poissonian, super-Poissonian, thermal, and heavy-tailed distributions like log-normal. The presented method can be used to simulate communication channels, calibrate the response of photon-number-resolving detectors, or probe physical phenomena sensitive to photon statistics.

The distributed quantum information processing and hybridization of quantum platforms raises increasing demands on the quality of light-matter interaction and realization of efficient quantum interfaces. This becomes particularly challenging for needed states possessing fundamental quantum non-Gaussian (QNG) aspects. They correspond to paramount resources in most potent applications of quantum technologies. We demonstrate the generation of light with provably QNG features from a warm atomic ensemble in a single-mode regime. The light is generated in a spontaneous four-wave mixing process in the presence of decoherence effects caused by a large atomic thermal motion. Despite its high sensitivity to any excess noise, direct observability of heralded QNG light could be achieved due to a combination of a fast resonant excitation, large spectral bandwidth, and a low absorption loss of resonant photons guaranteed by the source geometry.