Topic
Spin-½
About: Spin-½ is a research topic. Over the lifetime, 40423 publications have been published within this topic receiving 796639 citations.
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TL;DR: In this article, experimental measurements and tuning of LZ transitions between the dressed eigenlevels of a Bose-Einstein condensate (BEC) that is synthetically spin-orbit coupled are reported.
Abstract: The Landau-Zener (LZ) transition is one of the most fundamental phenomena in quantum dynamics. It describes nonadiabatic transitions between quantum states near an avoided crossing that can occur in diverse physical systems. Here we report experimental measurements and tuning of LZ transitions between the dressed eigenlevels of a Bose-Einstein condensate (BEC) that is synthetically spin-orbit (SO) coupled. We measure the transition probability as the BEC is accelerated through the SO avoided crossing and study its dependence on the coupling between the diabatic (bare) states, eigenlevel slope, and eigenstate velocity---the three parameters of the LZ model that are independently controlled in our experiments. Furthermore, we performed time-resolved measurements to demonstrate the breaking down of the spin-momentum locking of the spin-orbit-coupled BEC in the nonadiabatic regime, and we determined the diabatic switching time of the LZ transitions. Our observations show quantitative agreement with the LZ model and numerical simulations of the quantum dynamics in the quasimomentum space. The tunable LZ transition may be exploited to enable a spin-dependent atomtronic transistor.
142 citations
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TL;DR: In this paper, the authors derived the one-loop energy of a folded string rotating with angular momenta in AdS 3 × S 1 ⊂ AdS 5 × S 5 in the limit 1 ≪ J ≪ S, z = λ log (S / J ) / ( π J ) fixed.
142 citations
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TL;DR: In this article, a generalised Landau-Zener transition rate theory was proposed to explain the topological quantum interference of two tunnel paths of opposite windings in molecular clusters.
Abstract: The Landau-Zener method allows to measure very small tunnel splittings Δ in molecular clusters Fe8. The observed oscillations of Δ as a function of the magnetic field applied along the hard anisotropy axis are explained in terms of topological quantum interference of two tunnel paths of opposite windings. Studies of the temperature dependence of the Landau-Zener transition rate P gives access to the topological quantum interference between excited spin levels. The influence of nuclear spins is demonstrated by comparing P of the standard Fe8 sample with two isotopically substituted samples. The need of a generalised Landau-Zener transition rate theory is shown.
142 citations
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TL;DR: The spectrum of baryons with two heavy quarks can be related to the spectrum of mesons with Qq flavor quantum numbers as mentioned in this paper, where the interactions of heavy color triplet objects with the light degrees of freedom (i.e. quarks and gluons) are independent of the heavy quark's spin and mass.
142 citations
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TL;DR: In this article, a linear σ-model is used to describe the N and Δ as three quarks interacting via σ and π mesons, and the effects of confinement are neglected.
142 citations