1,314 research outputs found
Variational optimization of tensor-network states with the honeycomb-lattice corner transfer matrix
We develop a method of variational optimization of the infinite projected
entangled pair states on the honeycomb lattice. The method is based on the
automatic differentiation of the honeycomb lattice corner transfer matrix
renormalization group. We apply the approach to the antiferromagnetic
Heisenberg spin-1/2 model on the honeycomb lattice. The developed formalism
gives quantitatively accurate results for the main physical observables and has
a necessary potential for further extensions
Preparation and detection of magnetic quantum phases in optical superlattices
We describe a novel approach to prepare, detect and characterize magnetic
quantum phases in ultra-cold spinor atoms loaded in optical superlattices. Our
technique makes use of singlet-triplet spin manipulations in an array of
isolated double well potentials in analogy to recently demonstrated quantum
control in semiconductor quantum dots. We also discuss the many-body
singlet-triplet spin dynamics arising from coherent coupling between nearest
neighbor double wells and derive an effective description for such system. We
use it to study the generation of complex magnetic states by adiabatic and
non-equilibrium dynamics.Comment: 5 pages, 2 Figures, reference adde
Optical Superradiance from Nuclear Spin Environment of Single Photon Emitters
We show that superradiant optical emission can be observed from the polarized
nuclear spin ensemble surrounding a single photon emitter such as a single
quantum dot (QD) or Nitrogen-Vacancy (NV) center. The superradiant light is
emitted under optical pumping conditions and would be observable with realistic
experimental parameters.Comment: 4+ pages, 3 figures, considerably rewritten, conclusions unchanged,
accepted versio
Factors and mechanisms of productive secondary reservoirs formation in deep-lying oil and gas complexes. Article 1. Tectonophysical mechanisms of Lower Carboniferous quartzite-sandstones decompaction in the central part of the Dniprovsko-Donetska depression at the depths of more than 4.5 km
In the world, the scale of development of secondary reservoirs in decompaction rock bodies in a wide formation range is steadily increasing: from the crystalline basement of different ages of various oil and gas-bearing basins to terrigenous deposits with reduced primary porosity and carbonate formations. Development of hydrocarbon resources associated with secondary reservoirs of deep-seated complexes is the most important strategic direction of geological exploration. The results presented in this article are of fundamental importance, since they are based, firstly, mainly on the study of the core of deep-lying complexes, and secondly, on a significantly different (than in previous works) methodology (wide application of electron microscopic scanning with X-ray spectral probing and diffractometry), thirdly (and most importantly) – on a significantly different ideology. It is based on the concept of different genetic types of post-sedimentation transformations. Along with diagenesis and catagenesis, it is dislocation epigenesis and hypogene allogenesis with specific geodynamic and geothermodynamic regimes, including the special role of structural temperatures and pressures. In oil and gas-bearing basins of the continental-riftogenic (aulacogenic) type, the final stage of regional epigenesis is dislocation epigenesis with zonal and local manifestation of hypogene allogenesis. Gas and gas condensate deposits, as well as the main part of oil and heterophase deposits, are associated with this stage. The established regularities of the formation of secondary reservoirs are of particular importance for the effective development of the hydrocarbon potential of great depths
Equilibrium forms branching of a nanolayers system
In this work we analyze equilibrium forms branching of three parallel conductive micro/nanolayers which can be used as a sensor of internal or external mechanical and electrical parameters such as conductivity, tension force or gap between layers. Alteration of physical parameters can lead to symmetry breaking, i.e. asymmetrical deflection of outermost layers and nonzero deflection of middle, initially neutral layer. By slow current intensity variation in one of outermost layers, initial symmetry of the system can be achieved, thus determining the parameters alteration which had occurred
Storage of light in atomic vapor
We report an experiment in which a light pulse is decelerated and trapped in
a vapor of Rb atoms, stored for a controlled period of time, and then released
on demand. We accomplish this storage of light by dynamically reducing the
group velocity of the light pulse to zero, so that the coherent excitation of
the light is reversibly mapped into a collective Zeeman (spin) coherence of the
Rb vapor
TIME-FREQUENCY REPRESENTATION ENHANCEMENT: APPROACH BASED ON IMAGE FILTERING METHODS
The task of filtering of the time-frequency representations, obtained by the S-method, using advanced digital image processing filters, both local and nonlocal is considered. Such enhancement is important for design of the time-varying filters for processing of nonstationary frequency modulated signals. The class of local filters is represented by spatial domain filtering using median and related filters. Orthogonal transform based denoising is represented by DCT domain filtering. The block matching 3-D filter is considered as a representative of nonlocal filter class. It is demonstrated that the noise in the time-frequency representations based on Smethod has rather complicated nature: non-Gaussian pdf, spatially correlated properties with varying parameters. It is shown that direct application of the considered filters to such a challenging noisy environment is not possible. Then, several filter modifications are proposed and analyzed with respect to integral and local parameters – MSE and MAE. The block matching 3-D filter is shown to provide the best results but at the expense of quality loss in representation of weak components
Socio-psychological characteristics elections with weak content
The socio-psychological features of elections with a weak content have been considered. The factors of interest of the electorate in such elections have been allocated. The main socio-psychological features of elections with a weak content, that determine the effectiveness of the use of political technologies have been noted. The causal typology of the features of elections with weak content, including formal, socio-psychological and political-technological features, has been presented. The process of effective information support of the election campaign has been analyzed and the conclusion has been made about the need for quality monitoring of candidates ‘ ratings in any election campaign. Conclusions have been drawn about the possibility of using the identified socio-psychological features of elections with low content in election campaigns
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