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Interference between two indistinguishable electrons from independent sources
Neder, I.,Ofek, N.,Chung, Y.,Heiblum, M.,Mahalu, D.,Umansky, V. Nature Publishing Group 2007 Nature Vol.448 No.7151
Very much like the ubiquitous quantum interference of a single particle with itself, quantum interference of two independent, but indistinguishable, particles is also possible. For a single particle, the interference is between the amplitudes of the particle’s wavefunctions, whereas the interference between two particles is a direct result of quantum exchange statistics. Such interference is observed only in the joint probability of finding the particles in two separated detectors, after they were injected from two spatially separated and independent sources. Experimental realizations of two-particle interferometers have been proposed; in these proposals it was shown that such correlations are a direct signature of quantum entanglement between the spatial degrees of freedom of the two particles (‘orbital entanglement’), even though they do not interact with each other. In optics, experiments using indistinguishable pairs of photons encountered difficulties in generating pairs of independent photons and synchronizing their arrival times; thus they have concentrated on detecting bunching of photons (bosons) by coincidence measurements. Similar experiments with electrons are rather scarce. Cross-correlation measurements between partitioned currents, emanating from one source, yielded similar information to that obtained from auto-correlation (shot noise) measurements. The proposal of ref. 3 is an electronic analogue to the historical Hanbury Brown and Twiss experiment with classical light. It is based on the electronic Mach–Zehnder interferometer that uses edge channels in the quantum Hall effect regime. Here we implement such an interferometer. We partitioned two independent and mutually incoherent electron beams into two trajectories, so that the combined four trajectories enclosed an Aharonov–Bohm flux. Although individual currents and their fluctuations (shot noise measured by auto-correlation) were found to be independent of the Aharonov–Bohm flux, the cross-correlation between current fluctuations at two opposite points across the device exhibited strong Aharonov–Bohm oscillations, suggesting orbital entanglement between the two electron beams.
In Vitro Real-Time Interactions of Cranberry Constituents with Immobilized Fructosyltransferase
Mark Feldman,Ervin I. Weiss,Itzhak Ofek,Moshe Shemesh,Doron Steinberg 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.5
Cranberry has been proposed as an anti-biofilm agent that does not kill bacteria, but rather prevents the pathogen from survival in the host. This can be achieved by inhibiting the function of virulent factors essential for the pathogen to persist in a host environment. The oral bacterial enzyme fructosyltransferase (FTF) plays an important role in the pathogenesis of dental diseases. The real-time interaction of cranberry nondialyzable material (NDM) with immobilized FTF was investigated using the surface plasmon resonance (SPR) technique. To determine its binding efficiency, NDM at concentrations between 0μg/mL and 200μg/mL was applied onto the immobilized FTF. The effect of NDM or other polyphenols, myricetin, and epicatechin on FTF enzymatic activity was evaluated by applying the above compounds and sucrose onto immobilized FTF. Salivary amylase was applied with NDM onto immobilized FTF to explore the effect on NDM–FTF interaction. Our results show that NDM firmly attaches to immobilized FTF in a dose-dependent manner, whereas the presence of salivary amylase reduced this binding interaction. Using nonlinear regression we calculated that the affinity constant of NDM applied alone (106 M−1) was fivefold higher than NDM in the presence of amylase (0.2×106 M−1). At 200μg/mL, NDM, introduced together with sucrose, inhibited the activity of immobilized FTF by 63% within minutes, in comparison with the control (sucrose alone). The effect of NDM was sustained even after it was washed off the immobilized FTF. Myricetin also strongly inhibited FTF activity, whereas epicatechin was less effective. The real-time SPR observation suggests that one of the anti-biofilm modes of action of NDM is an immediate and irreversible inhibitory effect on the activity of immobilized FTF, which is due to a strong binding affinity to the immobilized enzyme