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تسجيل مستخدم جديدTowards identification of a non-abelian state: observation of a quarter of electron charge at $ u=5/2$ quantum Hall state
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The fractional quantum Hall effect, where plateaus in the Hall resistance at values of coexist with zeros in the longitudinal resistance, results from electron correlations in two dimensions under a strong magnetic field. Current flows along the edges carried by charged excitations (quasi particles) whose charge is a fraction of the electron charge. While earlier research concentrated on odd denominator fractional values of $ u$, the observation of the even denominator $ u=5/2$ state sparked a vast interest. This state is conjectured to be characterized by quasiparticles of charge e/4, whose statistics is non-abelian. In other words, interchanging of two quasi particles may modify the state of the system to an orthogonal one, and does not just add a phase as in for fermions or bosons. As such, these quasiparticles may be useful for the construction of a topological quantum computer. Here we report data of shot noise generated by partitioning edge currents in the $ u=5/2$ state, consistent with the charge of the quasiparticle being e/4, and inconsistent with other potentially possible values, such as e/2 and e. While not proving the non-abelian nature of the $ u=5/2$ state, this observation is the first step toward a full understanding of these new fractional charges.
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We analyze charge-$e/4$ quasiparticle tunneling between the edges of a point contact in a non-Abelian model of the $ u=5/2$ quantum Hall state. We map this problem to resonant tunneling between attractive Luttinger liquids and use the time-dependent
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We report on results of numerical studies of the spin polarization of the half filled second Landau level, which corresponds to the fractional quantum Hall state at filling factor $ u=5/2$. Our studies are performed using both exact diagonalization a
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