scholarly journals Role of Majorana fermions in spin transport of anisotropic Kitaev model

2021 ◽  
Vol 104 (12) ◽  
Author(s):  
Hirokazu Taguchi ◽  
Yuta Murakami ◽  
Akihisa Koga ◽  
Joji Nasu
Keyword(s):  
Spin Transport ◽  
Majorana Fermions ◽  
Kitaev Model

scholarly journals Role of NiO in the nonlocal spin transport through thin NiO films on Y3Fe5O12

2021 ◽  
Vol 103 (14) ◽  
Author(s):  
Geert R. Hoogeboom ◽  
Geert-Jan N. Sint Nicolaas ◽  
Andreas Alexander ◽  
Olga Kuschel ◽  
Joachim Wollschläger ◽  
...  
Keyword(s):  
Spin Transport ◽  
Nio Films

scholarly journals Chaos on the hypercube

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Yiyang Jia ◽  
Jacobus J. M. Verbaarschot
Keyword(s):  
Magnetic Flux ◽  
Spectral Density ◽  
Hermite Polynomials ◽  
Weighted Sums ◽  
Majorana Fermions ◽  
Chord Diagrams ◽  
Magnetic Inversion ◽  
Constant Magnitude ◽  
Kitaev Model ◽  
Spectral Statistics

Abstract We analyze the spectral properties of a d-dimensional HyperCubic (HC) lattice model originally introduced by Parisi. The U(1) gauge links of this model give rise to a magnetic flux of constant magnitude ϕ but random orientation through the faces of the hypercube. The HC model, which also can be written as a model of 2d interacting Majorana fermions, has a spectral flow that is reminiscent of Maldacena-Qi (MQ) model, and its spectrum at ϕ = 0, actually coincides with the coupling term of the MQ model. As was already shown by Parisi, at leading order in 1/d, the spectral density of this model is given by the density function of the Q-Hermite polynomials, which is also the spectral density of the double-scaled Sachdev-Ye-Kitaev model. Parisi demonstrated this by mapping the moments of the HC model to Q-weighted sums on chord diagrams. We point out that the subleading moments of the HC model can also be mapped to weighted sums on chord diagrams, in a manner that descends from the leading moments. The HC model has a magnetic inversion symmetry that depends on both the magnitude and the orientation of the magnetic flux through the faces of the hypercube. The spectrum for fixed quantum number of this symmetry exhibits a transition from regular spectra at ϕ = 0 to chaotic spectra with spectral statistics given by the Gaussian Unitary Ensembles (GUE) for larger values of ϕ. For small magnetic flux, the ground state is gapped and is close to a Thermofield Double (TFD) state.

scholarly journals Random k-Body Ensembles for Chaos and Thermalization in Isolated Systems

Entropy ◽  
2018 ◽  
Vol 20 (7) ◽  
pp. 541 ◽  
Author(s):  
Venkata Kota ◽  
Narendra Chavda
Keyword(s):  
Hermite Polynomials ◽  
Point Group ◽  
Majorana Fermions ◽  
Many Body ◽  
Boson Systems ◽  
Random Matrix Ensembles ◽  
Isolated Systems ◽  
Group Symmetries ◽  
Statistical Relaxation

Embedded ensembles or random matrix ensembles generated by k-body interactions acting in many-particle spaces are now well established to be paradigmatic models for many-body chaos and thermalization in isolated finite quantum (fermion or boson) systems. In this article, briefly discussed are (i) various embedded ensembles with Lie algebraic symmetries for fermion and boson systems and their extensions (for Majorana fermions, with point group symmetries etc.); (ii) results generated by these ensembles for various aspects of chaos, thermalization and statistical relaxation, including the role of q-hermite polynomials in k-body ensembles; and (iii) analyses of numerical and experimental data for level fluctuations for trapped boson systems and results for statistical relaxation and decoherence in these systems with close relations to results from embedded ensembles.

scholarly journals The role of heavy metal ions on spin transport in organic semiconductors

2015 ◽  
Vol 17 (1) ◽  
pp. 013004 ◽  
Author(s):  
B B Chen ◽  
S Wang ◽  
S W Jiang ◽  
Z G Yu ◽  
X G Wan ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Organic Semiconductors ◽  
Heavy Metal Ions ◽  
Spin Transport

scholarly journals Tunable spin transport in CrAs: Role of correlation effects

2005 ◽  
Vol 71 (8) ◽  
Author(s):  
L. Chioncel ◽  
M. I. Katsnelson ◽  
G. A. de Wijs ◽  
R. A. de Groot ◽  
A. I. Lichtenstein
Keyword(s):  
Spin Transport ◽  
Correlation Effects

scholarly journals Universal Spin Transport and Quantum Bounds for Unitary Fermions

2019 ◽  
Vol 10 (1) ◽  
pp. 85-106 ◽  
Author(s):  
Tilman Enss ◽  
Joseph H. Thywissen
Keyword(s):  
Spin Transport ◽  
Condensed Matter ◽  
Transport Coefficients ◽  
Lattice Systems ◽  
Theoretical Understanding ◽  
Strongly Interacting ◽  
Open Questions ◽  
Broad Interest ◽  
Quasiparticle Picture

We review recent advances in experimental and theoretical understanding of spin transport in strongly interacting Fermi gases. The central new phenomenon is the observation of a lower bound on the (bare) spin diffusivity in the strongly interacting regime. Transport bounds are of broad interest for the condensed matter community, with a conceptual similarity to observed bounds in shear viscosity and charge conductivity. We discuss the formalism of spin hydrodynamics, how dynamics are parameterized by transport coefficients, the effect of confinement, the role of scale invariance, the quasiparticle picture, and quantum critical transport. We conclude by highlighting open questions, such as precise theoretical bounds, relevance to other phases of matter, and extensions to lattice systems.

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