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, the modification of the local electronic structure caused by a single local impurity on the surface of a 3D topological insulator was studied and it was shown that the local density of states around the Dirac point of the electronic spectrum at the surface is significantly disrupted near the impurity by the creation of low-energy resonance state(s).
Abstract: We calculate the modification of the local electronic structure caused by a single local impurity on the surface of a three-dimensional topological insulator. We find that the local density of states around the Dirac point of the electronic spectrum at the surface is significantly disrupted near the impurity by the creation of low-energy resonance state(s)---however, this is not sufficient to (locally) destroy the Dirac point. We also calculate the nontrivial spin textures created near the magnetic impurities and discover anisotropic Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling between them.
170 citations
TL;DR: Using Bogoliubov theory, the excitation spectrum of a spinor Bose-Einstein condensed gas with an equal Rashba and Dresselhaus spin-orbit coupling in the stripe phase is calculated and the emergence of a double gapless band structure is pointed out.
Abstract: Using Bogoliubov theory we calculate the excitation spectrum of a spinor Bose-Einstein condensed gas with an equal Rashba and Dresselhaus spin-orbit coupling in the stripe phase. The emergence of a double gapless band structure is pointed out as a key signature of Bose-Einstein condensation and of the spontaneous breaking of translational invariance symmetry. In the long wavelength limit the lower and upper branches exhibit, respectively, a clear spin and density nature. For wave vectors close to the first Brillouin zone, the lower branch acquires an important density character responsible for the divergent behavior of the structure factor and of the static response function, reflecting the occurrence of crystalline order. The sound velocities are calculated as functions of the Raman coupling for excitations propagating orthogonal and parallel to the stripes. Our predictions provide new perspectives for the identification of supersolid phenomena in ultracold atomic gases.
170 citations
TL;DR: In this article, it was shown that the AdS4 higher spin gauge theory is dual to the theory of 3D conformal currents of all spins interacting with 3d conformal higher spin fields of Chern?Simons type.
Abstract: Holographic duality is argued to relate classes of models that have equivalent unfolded formulation, hence exhibiting different space-time visualizations for the same theory. This general phenomenon is illustrated by the AdS4 higher spin gauge theory shown to be dual to the theory of 3d conformal currents of all spins interacting with 3d conformal higher spin fields of Chern?Simons type. Generally, the resulting 3d boundary conformal theory is nonlinear, providing an interacting version of the 3d boundary sigma model conjectured by Klebanov and Polyakov to be dual to the AdS4 higher spin theory in the large N limit. Being a gauge theory, it escapes the conditions of the theorem of Maldacena and Zhiboedov, which force a 3d boundary conformal theory to be free. Two reductions of particular higher spin gauge theories where boundary higher spin gauge fields decouple from the currents and which have free-boundary duals are identified. Higher spin holographic duality is also discussed for the cases of AdS3/CFT2 and duality between higher spin theories and nonrelativistic quantum mechanics. In the latter case, it is shown in particular that (dS) AdS geometry in the higher spin setup is dual to the (inverted) harmonic potential in the quantum-mechanical setup.This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ?Higher spin theories and holography?.
169 citations
TL;DR: In this article, the half-integer quantum Hall (QH) effect in two-dimensional electron and hole gas is studied in high quality graphene samples and a distinctive halfinteger QH effect is discovered with QH plateaus appearing at a filling factor sequence, ν = 4 (n + 1 / 2 ), where n is the Landau level (LL) index.
169 citations
TL;DR: In this paper, the hydrodynamic theory of spin waves is extended to a magnetic system such as a spin glass or a crystal with helical spin order, in which there are equilibrium magnetizations on different sites, with spin directions that are not collinear.
Abstract: The hydrodynamic theory of spin waves is extended to a magnetic system such as a spin glass or a crystal with helical spin order, in which there are equilibrium magnetizations on different sites, with spin directions that are not collinear. If the total magnetization is zero and if the interactions are assumed to be isotropic in spin space, one predicts well-defined spin waves at small wave vectors $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}$, with a linear dispersion relation, and three polarizations for each value of $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}$. The hydrodynamic assumption of a finite spin-stiffness constant may be questionable, however, for the spin glass. Nonzero magnetization is discussed briefly.
169 citations