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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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Journal ArticleDOI
16 Aug 2019-Science
TL;DR: The discovery of spin-triplet superconductivity in UTe2, featuring a transition temperature of 1.6 kelvin and a very large and anisotropic upper critical field exceeding 40 teslas, suggests that UTe1 is related to ferromagnetic superconductors such as UGe2, URhGe, and UCoGe, however, the lack of magnetic order and the observation of quantum critical scaling place U Te2 at the paramagnetic end of this ferrom
Abstract: Spin-triplet superconductors potentially host topological excitations that are of interest for quantum information processing. We report the discovery of spin-triplet superconductivity in UTe2, featuring a transition temperature of 1.6 kelvin and a very large and anisotropic upper critical field exceeding 40 teslas. This superconducting phase stability suggests that UTe2 is related to ferromagnetic superconductors such as UGe2, URhGe, and UCoGe. However, the lack of magnetic order and the observation of quantum critical scaling place UTe2 at the paramagnetic end of this ferromagnetic superconductor series. A large intrinsic zero-temperature reservoir of ungapped fermions indicates a highly unconventional type of superconducting pairing.

323 citations

Posted Content
TL;DR: In this article, the imprint of new particles on the primordial cosmological fluctuations was studied and the role of symmetries in determining the final result was emphasized, which can be viewed as arising from the interference between two processes.
Abstract: We study the imprint of new particles on the primordial cosmological fluctuations. New particles with masses comparable to the Hubble scale produce a distinctive signature on the non-gaussianities. This feature arises in the squeezed limit of the correlation functions of primordial fluctuations. It consists of particular power law, or oscillatory, behavior that contains information about the masses of new particles. There is an angular dependence that gives information about the spin. We also have a relative phase that crucially depends on the quantum mechanical nature of the fluctuations and can be viewed as arising from the interference between two processes. While some of these features were noted before in the context of specific inflationary scenarios, here we give a general description emphasizing the role of symmetries in determining the final result.

322 citations

Journal ArticleDOI
05 Nov 2010-Science
TL;DR: The underlying order of the various broken-symmetry states in bilayer graphene suspended between top and bottom gate electrodes was investigated and the order parameter was deduced by controllably breaking the spin and sublattice symmetries.
Abstract: The single-particle energy spectra of graphene and its bilayer counterpart exhibit multiple degeneracies that arise through inherent symmetries. Interactions among charge carriers should spontaneously break these symmetries and lead to ordered states that exhibit energy gaps. In the quantum Hall regime, these states are predicted to be ferromagnetic in nature, whereby the system becomes spin polarized, layer polarized, or both. The parabolic dispersion of bilayer graphene makes it susceptible to interaction-induced symmetry breaking even at zero magnetic field. We investigated the underlying order of the various broken-symmetry states in bilayer graphene suspended between top and bottom gate electrodes. We deduced the order parameter of the various quantum Hall ferromagnetic states by controllably breaking the spin and sublattice symmetries. At small carrier density, we identified three distinct broken-symmetry states, one of which is consistent with either spontaneously broken time-reversal symmetry or spontaneously broken rotational symmetry.

321 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that, at leading order in the 1 N c expansion, none of the proton spin would be carried by quarks in the chiral limit where mq = 0.

321 citations

Journal ArticleDOI
TL;DR: In this article, the ground state energy and momentum distribution of the electrons are expanded from the atomic limit for the half-filled Hubbard model by using the spin correlation functions of the spin 1/2 Heisenberg model.
Abstract: The ground-state energy E and momentum distribution nk of the electrons are expanded from the atomic limit for the half-filled Hubbard model. The coefficients of expansion are represented by the spin correlation functions of the spin 1/2 Heisenberg model. Using the spin-wave theory, approximate values of coefficients are calculated for the square lattice and the simple cubic lattice. In one dimension, the theory shows a good agreement with the exact solution. An effective spin Hamiltonian for the half-filled Hubbard model with arbitrary hopping integrals is obtained up to the fifth order. It is shown that the fourth term contains four spin interactions.

319 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202234
20212,352
20201,787
20191,748
20181,696
20171,621