Search results for "Non-linear sigma model"

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The Nonlinear σ Model

1989

The nonlinear (principal) σ model has been for a long time a theoretical laboratory to test different approaches for quantizing classical field theories. Here we shall discuss as an application of the current algebra representation theory a construction of the quantized σ model.

PhysicsTheoretical physicsNonlinear systemLine bundleField (physics)Current algebraClassical field theoryRepresentation theorySymplectic manifoldNon-linear sigma model
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Magnetoelectric effects in superconductors due to spin-orbit scattering : Nonlinear σ-model description

2021

We suggest a generalization of the nonlinear σ model for diffusive superconducting systems to account for magnetoelectric effects due to spin-orbit scattering. In the leading orders of spin-orbit strength and gradient expansion, it includes two additional terms responsible for the spin-Hall effect and the spin-current swapping. First, assuming a delta-correlated disorder, we derive the terms from the Keldysh path integral representation of the generating functional. Then we argue phenomenologically that they exhaust all invariants allowed in the effective action to the leading order in the spin-orbit coupling (SOC). Finally, the results are confirmed by a direct derivation of the saddle-poi…

Physicsmagneettiset ominaisuudetScatteringCondensed Matter - Superconductivity02 engineering and technology021001 nanoscience & nanotechnologyCoupling (probability)01 natural sciences7. Clean energy3. Good healthsuprajohteetNonlinear systemQuantum mechanicsspin (kvanttimekaniikka)0103 physical sciencesPath integral formulationBorn approximation010306 general physics0210 nano-technologyEffective actionNon-linear sigma modelSpin-½
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