A quantum volume hologram

We propose a new scheme for parallel spatially multimode quantum memory for light. The scheme is based on counter-propagating quantum signal wave and strong classical reference wave, like in a classical volume hologram, and therefore can be called a quantum volume hologram. The medium for the hologram consists of a spatially extended ensemble of atoms placed in a magnetic field. The write-in and read-out of this quantum hologram is as simple as that of its classical counterpart and consists of a single pass illumination. In addition we show that the present scheme for a quantum hologram is less sensitive to diffraction and therefore is capable of achieving higher density of storage of spatial modes as compared to previous proposals. A quantum hologram capable of storing entangled images can become an important ingredient in quantum information processing and quantum imaging.Comment: 8 pages, 2 figure

Power law correlations in galaxy distribution and finite volume effects from the Sloan Digital Sky Survey Data Release Four

We discuss the estimation of galaxy correlation properties in several volume limited samples, in different sky regions, obtained from the Fourth Data Release of the Sloan Digital Sky Survey. The small scale properties are characterized through the determination of the nearest neighbor probability distribution. By using a very conservative statistical analysis, in the range of scales [0.5,~30] Mpc/h we detect power-law correlations in the conditional density in redshift space, with an exponent \gamma=1.0 \pm 0.1. This behavior is stable in all different samples we considered thus it does not depend on galaxy luminosity. In the range of scales [~30,~100] Mpc/h we find evidences for systematic unaveraged fluctuations and we discuss in detail the problems induced by finite volume effects on the determination of the conditional density. We conclude that in such range of scales there is an evidence for a smaller power-law index of the conditional density. However we cannot distinguish between two possibilities: (i) that a crossover to homogeneity (corresponding to \gamma=0 in the conditional density) occurs before 100 Mpc/h, (ii) that correlations extend to scales of order 100 Mpc/h (with a smaller exponent 0 < \gamma <1). We emphasize that galaxy distributions in these samples present large fluctuations at the largest scales probed, corresponding to the presence of large scale structures extending up to the boundaries of the present survey. Finally we discuss several differences between the behavior of the conditional density in mock galaxy catalogs built from cosmological N-body simulations and real data. We discuss some theoretical implications of such a fact considering also the super-homogeneous features of primordial density fields.Comment: 13 pages, 19 figures, to be publsihed in Astronomy and Astrophysic

New Social World: The Great Power of the Network

At the early beginning of the 21st century, it was impossible to imagine how fast the Internet would develop. It was also not obvious that the worldwide network would actually become available in all parts of the planet, and the network itself would become the basis for the birth and development of new global products - social networks, communications, and services. According to the International Telecommunication Union, the Internet and new digital products along twenty years have almost completely absorbed the population of developed countries (87%) and are growing rapidly in developing countries (47%)[1]. The affordable cost of communication for the majority of the population together with free communication services create the basis for the emergence of not only new products but also a constant increase in the number of digital services, which quite recently could only be obtained offline. Together with large digital government services, commercial networks, communicators, and services are creating a new social structure capable of independent machine learning and development. The work aims to show that much faster than it was supposed new digital products will intertwine with each other, forming a new social platform, which is called a New Social World. The analysis of sociological works on this topic together with an analysis of practical research on the Internet and new digital products confirms this assumption. Despite strict user agreements, global online monitoring, constant online control and full access to the data of each user, more and more people become users of social networks and services, and most social network users become loyal users of other new products and services, easily switching on digital consumption and consumption of real products and services provided online. The new social reality, generated by the powerful interweaving of the world's digital products and services will forever change the sociocultural and media world. An urgent and constant study of this phenomenon is necessary since the ways of its further development are unpredictable both in relation to the existence of traditional, social, national identification and with the existence of traditional state institutions and states.   Cite this paper: Komissarov, Sergey N.; Vasilyev, Nikolay A. (2021). "New Social World: The Great Power of the Network" Journal of Social Sciences: Transformations &amp; Transitions (JOSSTT) 1(02):08. DOI: https://doi.org/10.52459/josstt1281221

New spectral functions of the near-ground albedo derived from aircraft diffraction spectrometer observations

The airborne spectral observations of the upward and downward irradiances are revisited to investigate the dependence of the near-ground albedo as a function of wavelength in the entire solar spectrum for different surfaces (sand, water, snow) and under different conditions (clear or cloudy sky). The radiative upward and downward fluxes were determined by a diffraction spectrometer flown on a research aircraft that was performing multiple flight paths near the ground. The results obtained show that the near-ground albedo does not generally increase with increasing wavelengths for all kinds of surfaces as is widely believed today. Particularly, in the case of water surfaces it was found that the albedo in the ultraviolet region is more or less independent of the wavelength on a long-term basis. Interestingly, in the visible and near-infrared spectra the water albedo obeys an almost constant power-law relationship with wavelength. In the case of sand surfaces it was found that the sand albedo is a quadratic function of wavelength, which becomes more accurate if the ultraviolet wavelengths are neglected. Finally, it was found that the spectral dependence of snow albedo behaves similarly to that of water, i.e. both decrease from the ultraviolet to the near-infrared wavelengths by 20–50%, despite the fact that their values differ by one order of magnitude (water albedo being lower). In addition, the snow albedo vs. ultraviolet wavelength is almost constant, while in the visible near-infrared spectrum the best simulation is achieved by a second-order polynomial, as in the case of sand, but with opposite slopes

Some results of cislunar plasma research

The main results of plasma cislunar investigations, carried out during Luna-19 and Luna-22 spacecraft flights by means of dual frequency dispersion interferrometry, are briefly outlined. It is shown that a thin layer of plasma, with a height of several tens of kilometers and a maximum concentration of the order 1,000 electrons/cu cm exists above the solar illuminated lunar surface. A physical model of the formation and existence of such a plasma in cislunar space is proposed, taking into account the influence of local magnetic areas on the moon