Social and Economic Consequences of Forest Decline in Czechoslovakia

The forests of Czechoslovakia are seriously endangered by air pollution. Another factor contributing to forest decline could be the historical development of silviculture. The study discusses the contemporary state of forests in Czechoslovakia and the outlook to 2000. Continued forest decline could seriously endanger the non-timber functions of forests. The importance of the water-controlling function of forests and its economic efficiency are broadly discussed. The largest part of the paper deals with the influence of forest decline on recreation. Even with limited data, one can observe a continually growing demand for recreation in mountain areas with damaged forests. The reasons lie in the historical development and peculiar features of recreation in this socialist society. The difficulties of forecasting peoples' behavior and their recreational demands is recognized. The last part of the paper deals with the influence of forest decline on production in the wood-processing and pulp-and-paper industries and strategies for their future. It will be necessary to change the structure of the forest-products sector and to investigate the newest technologies for the best utilization of all wood grown, which due to forest damage and the ensuing compulsory sanitation fellings will increase first and then after some years decrease. The study shows that forest decline in Czechoslovakia will lead to high economic losses and high consequent costs and investments in future decades, and can also have serious social consequences even if none have yet been manifested

Multiparameter Quantum Metrology of Incoherent Point Sources: Towards Realistic Superresolution

We establish the multiparameter quantum Cram\'er-Rao bound for simultaneously estimating the centroid, the separation, and the relative intensities of two incoherent optical point sources using alinear imaging system. For equally bright sources, the Cram\'er-Rao bound is independent of the source separation, which confirms that the Rayleigh resolution limit is just an artifact of the conventional direct imaging and can be overcome with an adequate strategy. For the general case of unequally bright sources, the amount of information one can gain about the separation falls to zero, but we show that there is always a quadratic improvement in an optimal detection in comparison with the intensity measurements. This advantage can be of utmost important in realistic scenarios, such as observational astronomy.Comment: 5 pages, 3 figures. Comments welcome

Experimental violation of a Bell-like inequality with optical vortex beams

Optical beams with topological singularities have a Schmidt decomposition. Hence, they display features typically associated with bipartite quantum systems; in particular, these classical beams can exhibit entanglement. This classical entanglement can be quantified by a Bell inequality formulated in terms of Wigner functions. We experimentally demonstrate the violation of this inequality for Laguerre-Gauss (LG) beams and confirm that the violation increases with increasing orbital angular momentum. Our measurements yield negativity of the Wigner function at the origin for \LG_{10} beams, whereas for \LG_{20} we always get a positive value.Comment: 6 pages, 4 eps-color figures. Comments welcome

Time-Multiplexed Measurements of Nonclassical Light at Telecom Wavelengths

We report the experimental reconstruction of the statistical properties of an ultrafast pulsed type-II parametric down conversion source in a periodically poled KTP waveguide at telecom wavelengths, with almost perfect photon-number correlations. We used a photon-number-resolving time-multiplexed detector based on a fiber-optical setup and a pair of avalanche photodiodes. By resorting to a germane data-pattern tomography, we assess the properties of the nonclassical light states states with unprecedented precision.Comment: 4.5 pages, 5 color figues. Comments welcome

Incomplete quantum state estimation: a comprehensive study

We present a detailed account of quantum state estimation by joint maximization of the likelihood and the entropy. After establishing the algorithms for both perfect and imperfect measurements, we apply the procedure to data from simulated and actual experiments. We demonstrate that the realistic situation of incomplete data from imperfect measurements can be handled successfully.Comment: 11 pages, 10 figure

Efficient algorithm for optimizing data pattern tomography

We give a detailed account of an efficient search algorithm for the data pattern tomography proposed by J. Rehacek, D. Mogilevtsev, and Z. Hradil [Phys. Rev. Lett.~\textbf{105}, 010402 (2010)], where the quantum state of a system is reconstructed without a priori knowledge about the measuring setup. The method is especially suited for experiments involving complex detectors, which are difficult to calibrate and characterize. We illustrate the approach with the case study of the homodyne detection of a nonclassical photon state.Comment: 5 pages, 5 eps-color figure

Intensity-based axial localization at the quantum limit

We derive fundamental precision bounds for single-point axial localization. For Gaussian beams, this ultimate limit can be achieved with a single intensity scan, provided the camera is placed at one of two optimal transverse detection planes. Hence, for axial localization there is no need of more complicated detection schemes. The theory is verified with an experimental demonstration of axial resolution 3 orders of magnitude below the classical depth of focus

Enhancing axial localization with wavefront control

Enhancing the ability to resolve axial details is crucial in three-dimensional optical imaging. We provide experimental evidence showcasing the ultimate precision achievable in axial localization using vortex beams. For Laguerre-Gauss (LG) beams, this remarkable limit can be attained with just a single intensity scan. This proof-of-principle demonstrates that microscopy techniques based on LG vortex beams can potentially benefit from the introduced quantum-inspired superresolution protocol.Comment: 10 pages, 6 figures. Comments welcom

Optical resolution from Fisher information

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