761 research outputs found

    Edge Channel Interference Controlled by Landau Level Filling

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    We study the visibility of Aharonov-Bohm interference in an electronic Mach-Zehnder interferometer (MZI) in the integer quantum Hall regime. The visibility is controlled by the filling factor ν\nu and is observed only between ν2.0\nu \approx 2.0 and 1.0, with an unexpected maximum near ν=1.5\nu=1.5. Three energy scales extracted from the temperature and voltage dependences of the visibility change in a very similar way with the filling factor, indicating that the different aspects of the interference depend sensitively on the local structure of the compressible and incompressible strips forming the quantum Hall edge channels.Comment: 5 pages, 5 figures, final version accepted for publication in Phys. Rev.

    Search for Spatial Structures at Scales Z~1. III. The Effect of Lensing on QSO ?

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    We carried out a search for peak inhomogeneities in the distribution of matter - namely clumps and voids, within the range Z ~ 1-3. We used a new method, based on the lensing of quasars by a combination of lenses, belonging to the above sought inhomogeneities in the matter distribution. This work confirms the evidence of the existence of inhomogeneities found by us earlier - of a clump (superattractor N.1), and of a void (supervoid). Besides, the existence of a new gigantic clump (superattractor N.2) was also discovered at Z ~ 3. These clumps could well serve as centers of the Bose-condensation in the early Universe; in particular - as Anselm's arion condensate, which leads to the formation of quasiperiodic structures with a period p ~ 100-200 Mpc.Comment: 22 pages, 2 figures, 6 tables. submitted to Astrophys.& Space Sc

    Counting Statistics and Dephasing Transition in an Electronic Mach-Zehnder Interferometer

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    It was recently suggested that a novel type of phase transition may occur in the visibility of electronic Mach-Zehnder Interferometers. Here, we present experimental evidence for the existence of this transition. The transition is induced by strongly non-Gaussian noise that originates from the strong coupling of a quantum point contact to the interferometer. We provide a transparent physical picture of the effect, by exploiting a close analogy to the neutrino-oscillations of particle physics. In addition, our experiment constitutes a probe of the singularity of the elusive full counting statistics of a quantum point contact.Comment: 7 pages, 4 figures (+Supplement 8 pages, 9 figures

    Historical and cultural heritage as a factor for the tourist development of a city

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    The article considers the influence of historical and cultural heritage preservation on the development of the tourist potential of Kazan. Today, the protection of cultural heritage is one of the state priorities. The Republic of Tatarstan is distinguished by a rich cultural heritage. Multicultural and multi-confessional nature are present on this land traditionally. The capital of the republic - the city of Kazan - is visited annually by millions of tourists. The authors pay a special attention to the most visited tourist sites of the city: the museum-reserve "Kazan Kremlin", the Old-Tatar Sloboda, the Kazan Bogoroditsky Monastery and the historical center. In recent years, full-scale works have been carried out in the field of cultural heritage preservation, in particular on designated sites, whose results are now witnessed by the residents and the tourists of Kazan. In order to popularize the cultural heritage and attract the tourists to the city, Kazan museums conduct an active exhibition, methodical, publishing and other activities. All necessary infrastructure for the reception of tourists is created in the historical center of the city: hotels, food and specialized trade places. The cultural heritage of the city and modern tourist realities do not contradict, but complement each other harmoniously.peer-reviewe

    Nonlocal vortex motion in mesoscopic amorphous Nb0.7Ge0.3 structures

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    We study nonlocal vortex transport in mesoscopic amorphous Nb0.7Ge0.3 samples. A dc current I is passed through a wire connected via a perpendicular channel, of a length L= 2-5 um, with a pair of voltage probes where a nonlocal response Vnl ~ I is measured. The maximum of Rnl=Vnl/I for a given temperature occurs at an L-independent magnetic field and is proportional to 1/L. The results are interpreted in terms of the dissipative vortex motion along the channel driven by a remote current, and can be understood in terms of a simple model.Comment: 4 pages, 3 figure

    Hadronic Production of the Doubly Charmed Baryon Ξcc\Xi_{cc} with Intrinsic Charm

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    The effects of the intrinsic charm on the hadronic production of Ξcc\Xi_{cc} are studied. By taking reasonable intrinsic charm component into account, the change of the theoretical prediction on the production of Ξcc\Xi_{cc} for LHC and Tevatron is small, but in contrast it may enhance significantly for SELEX. The reason is that the collision energy at LHC and Tevatron is so large that the gluon-gluon fusion sub-process, which is irrelevant to intrinsic charm, becomes dominant. But the situation for SELEX is quite different. Our numerical results for SELEX show that by considering all the contributions from various sub-processes, the predicted cross-section may be enhanced by a factor so big as 10210^2 due to a modulating intrinsic charm being taken into account. Therefore, the hadronic production of Ξcc\Xi_{cc} at SELEX may be sensitive enough in observing the intrinsic charm inside the incident hadrons.Comment: 18 pages, 8 figures. More discussions are adde
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