Spin Effects in Polariton Condensates: From Half-Solitons to Analogues of Wormholes

This chapter is devoted to one of key phenomena in the field of spin physics, namely, resonant absorption of electromagnetic waves under conditions where the Zeeman splitting of spin levels in magnetic field is equal to photon energy. This method is particularly important for identification of nuclear spin effects, because resonance spectra provide fingerprints of different involved spin species and make it possible to distinguish different nuclear isotopes. As discussed in this chapter the nuclear magnetic resonance provides also an access to local magnetic fields acting on nuclear spins. These fields are caused by the magnetic interactions between the nuclei and by the quadrupole splittings of nuclear spin states in anisotropic crystalline environment. Manifestations of spin resonance in optical responses of semiconductors–that is, optically detected magnetic resonance–are discussed.

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Spin effects in the effective field theory approach to Post-Minkowskian conservative dynamics

Journal of High Energy Physics ◽

10.1007/jhep06(2021)012 ◽

2021 ◽

Vol 2021 (6) ◽

Author(s):

Zhengwen Liu ◽

Rafael A. Porto ◽

Zixin Yang

Keyword(s):

Field Theory ◽

Effective Field Theory ◽

Scattering Problem ◽

Finite Size ◽

Effective Field ◽

Compact Objects ◽

Scattering Data ◽

Theory Approach ◽

Spin Effects ◽

Radial Action

Abstract Building upon the worldline effective field theory (EFT) formalism for spinning bodies developed for the Post-Newtonian regime, we generalize the EFT approach to Post-Minkowskian (PM) dynamics to include rotational degrees of freedom in a manifestly covariant framework. We introduce a systematic procedure to compute the total change in momentum and spin in the gravitational scattering of compact objects. For the special case of spins aligned with the orbital angular momentum, we show how to construct the radial action for elliptic-like orbits using the Boundary-to-Bound correspondence. As a paradigmatic example, we solve the scattering problem to next-to-leading PM order with linear and bilinear spin effects and arbitrary initial conditions, incorporating for the first time finite-size corrections. We obtain the aligned-spin radial action from the resulting scattering data, and derive the periastron advance and binding energy for circular orbits. We also provide the (square of the) center-of-mass momentum to $$ \mathcal{O}\left({G}^2\right) $$ O G 2 , which may be used to reconstruct a Hamiltonian. Our results are in perfect agreement with the existent literature, while at the same time extend the knowledge of the PM dynamics of compact binaries at quadratic order in spins.

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Geometric particle-in-cell methods for the Vlasov–Maxwell equations with spin effects

Journal of Plasma Physics ◽

10.1017/s0022377821000532 ◽

2021 ◽

Vol 87 (3) ◽

Author(s):

Nicolas Crouseilles ◽

Paul-Antoine Hervieux ◽

Yingzhe Li ◽

Giovanni Manfredi ◽

Yajuan Sun

Keyword(s):

Phase Space ◽

Maxwell Equations ◽

Stimulated Raman Scattering ◽

Extended Phase ◽

Five Dimensions ◽

Particle In Cell ◽

Spin Effects ◽

Dimensional Phase Space ◽

Spin Polarized ◽

Underdense Plasma

We propose a numerical scheme to solve the semiclassical Vlasov–Maxwell equations for electrons with spin. The electron gas is described by a distribution function $f(t,{\boldsymbol x},{{{\boldsymbol p}}}, {\boldsymbol s})$ that evolves in an extended 9-dimensional phase space $({\boldsymbol x},{{{\boldsymbol p}}}, {\boldsymbol s})$ , where $\boldsymbol s$ represents the spin vector. Using suitable approximations and symmetries, the extended phase space can be reduced to five dimensions: $(x,{{p_x}}, {\boldsymbol s})$ . It can be shown that the spin Vlasov–Maxwell equations enjoy a Hamiltonian structure that motivates the use of the recently developed geometric particle-in-cell (PIC) methods. Here, the geometric PIC approach is generalized to the case of electrons with spin. Total energy conservation is very well satisfied, with a relative error below $0.05\,\%$ . As a relevant example, we study the stimulated Raman scattering of an electromagnetic wave interacting with an underdense plasma, where the electrons are partially or fully spin polarized. It is shown that the Raman instability is very effective in destroying the electron polarization.

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