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 paper, the cone-like nature of the points in 2D HgTe quantum wells, where conduction and valance bands meet, has been investigated and shown to have similar properties to the spin-and valley-degeneracy of graphene.
Abstract: Most of the notable properties of graphene are a result of the cone-like nature of the points in its electronic structure where its conduction and valance bands meet. Similar structures arise in 2D HgTe quantum wells, but without the spin- and valley-degeneracy of graphene; their properties are also likely to be easier to control.
207 citations
TL;DR: In this article, the authors investigated pairwise quantum correlations as measured by the quantum discord as well as its classical counterpart in the thermodynamic limit of anisotropic spin-$1/2$ chains in a transverse magnetic field for both zero and finite temperatures.
Abstract: We investigate pairwise quantum correlation as measured by the quantum discord as well as its classical counterpart in the thermodynamic limit of anisotropic $\mathit{XY}$ spin-$1/2$ chains in a transverse magnetic field for both zero and finite temperatures. Analytical expressions for both classical and quantum correlations are obtained for spin pairs at any distance. In the case of zero temperature, it is shown that the quantum discord for spin pairs farther than second neighbors is able to characterize a quantum phase transition, even though pairwise entanglement is absent for such distances. For finite temperatures, we show that quantum correlations can be increased with temperature in the presence of a magnetic field. Moreover, in the $\mathit{XX}$ limit, thermal quantum discord is found to be dominant over classical correlation while the opposite scenario takes place for the transverse field Ising model limit.
207 citations
TL;DR: In this article, an algebraic approach to the analytic bootstrap in CFTs is presented, which maps the problem of doing large spin sums to any desired order to the problem solving a set of recursion relations.
Abstract: We develop an algebraic approach to the analytic bootstrap in CFTs. By acting with the Casimir operator on the crossing equation we map the problem of doing large spin sums to any desired order to the problem of solving a set of recursion relations. We compute corrections to the anomalous dimension of large spin operators due to the exchange of a primary and its descendants in the crossed channel and show that this leads to a Borel-summable expansion. We analyse higher order corrections to the microscopic CFT data in the direct channel and its matching to infinite towers of operators in the crossed channel. We apply this method to the critical O(N ) model. At large N we reproduce the first few terms in the large spin expansion of the known two-loop anomalous dimensions of higher spin currents in the traceless symmetric representation of O(N ) and make further predictions. At small N we present the results for the truncated large spin expansion series of anomalous dimensions of higher spin currents.
206 citations
TL;DR: In this article, a general algorithm for the construction of gravitational axial and conformal anomalies for fields of arbitrary spin is presented, and a variety of models are then displayed in which one or both of the anomalies vanish by cancellation.
206 citations
TL;DR: A model taking into account the spin lifetime and the escape tunneling time for carriers traveling back into the ferromagnetic contact reproduces accurately the experimental results.
Abstract: We report on spin injection experiments at a Co/Al 2 O 3 /GaAs interface with electrical detection. The application of a transverse magnetic field induces a large voltage drop AV at the interface as high as 1.2 mV for a current density of 0.34 nA · μm -2 . This represents a dramatic increase of the spin accumulation signal, well above the theoretical predictions for spin injection through a ferromagnet/ semiconductor interface. Such an enhancement is consistent with a sequential tunneling process via localized states located in the vicinity of the Al 2 O 3 /GaAs interface. For spin-polarized carriers these states act as an accumulation layer where the spin lifetime is large. A model taking into account the spin lifetime and the escape tunneling time for carriers traveling back into the ferromagnetic contact reproduces accurately the experimental results.
206 citations