272 research outputs found

    The hidden phase of Fock states; quantum non-local effects

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    We revisit the question of how a definite phase between Bose-Einstein condensates can spontaneously appear under the effect of measurements. We first consider a system that is the juxtaposition of two subsystems in Fock states with high populations, and assume that successive individual position measurements are performed. Initially, the relative phase is totally undefined, and no interference effect takes place in the first position measurement. But, while successive measurements are accumulated, the relative phase becomes better and better known, and a clear interference pattern emerges. It turns out that all observed results can be interpreted in terms of a pre-existing, but totally unknown, relative phase, which remains exactly constant during the experiment. We then generalize the results to more condensates. We also consider other initial quantum states than pure Fock states, and distinguish between intrinsic phase of a quantum state and phase induced by measurements. Finally, we examine the case of multiple condensates of spin states. We discuss a curious quantum effect, where the measurement of the spin angular momentum of a small number of particles can induce a big angular momentum in a much larger assembly of particles, even at an arbitrary distance. This spin observable can be macroscopic, assimilable to the pointer of a measurement apparatus, which illustrates the non-locality of quantum mechanics with particular clarity.Comment: a factor 1/2 added in equation (9); reference (30) completed, DOI adde

    Use of the industrial property system in Colombia (2018): A supervised learning application

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    The purpose of this paper is to establish ways to predict the spatial distribution of the use of the intellectual property system from information on industrial property applications and grants (distinctive signs and new creations) and copyright registrations in 2018. This will be done using supervised learning algorithms applied to information on industrial property applications and grants (trademarks and new creations) and copyright registrations in 2018. Within the findings, 4 algorithms were identified with a level of explanation higher than 80%: (i) Linear Regression, with an elastic network regularization; (ii) Stochastic Gradient Descent, with Hinge loss function, Ringe regularization (L2) and a constant learning rate; (iii) Neural Networks, with 1,000 layers, with Adam’s solution algorithm and 2,000 iterations; (iv) Random Forest, with 10 tree

    Effect of screening of the electron-phonon interaction on the temperature of Bose-Einstein condensation of intersite bipolarons

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    Here we consider an interacting electron-phonon system within the framework of extended Holstein-Hubbard model at strong enough electron-phonon interaction limit in which (bi)polarons are the essential quasiparticles of the system. It is assumed that the electron-phonon interaction is screened and its potential has Yukawa-type analytical form. An effect of screening of the electron-phonon interaction on the temperature of Bose-Einstein condensation of the intersite bipolarons is studied for the first time. It is revealed that the temperature of Bose-Einstein condensation of intersite bipolarons is higher in the system with the more screened electron-phonon interaction.Comment: 6 pages, 4 figure

    STUDY OF PROCESSES DURING ELECTROLYSIS OF ORGANIC DYE SOLUTION BY MEANS OF ION-PHOTON SPECTROMETRY

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    Spectral composition and quantum yield of radiation of the excited particles sputtered by an ion beam from surfaces of the dried sediment formed on electrodes at the electrolysis of the organic dye were studied by the method of ion-photon spectrometry. A correspondence between processes taking place near the electrode during the electrolysis of the organic dye solution and the composition of excited particles knocked out from the dried sediment formed on the electrodes was shown
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