Non existence d'un spin des photons

Existence and non-existence of skew branes

A skew brane is a codimension 2 submanifold in affine space such that the tangent spaces at any two distinct points are not parallel. We show that if an oriented closed manifold has a non-zero Euler characteristic χ then it is not a skew brane; generically, the number of oppositely oriented pairs of parallel tangent spaces is not less than χ/4. We give a version of this result for immersed surf...

Dicke quantum spin glass of atoms and photons.

Recent studies of strongly interacting atoms and photons in optical cavities have rekindled interest in the Dicke model of atomic qubits coupled to discrete photon cavity modes. We study the multimode Dicke model with variable atom-photon couplings. We argue that a quantum spin-glass phase can appear, with a random linear combination of the cavity modes superradiant. We compute atomic and photo...

Spin-Dependent Structure Functions of Real and Virtual Photons

The implications of the positivity constraint, |g γ(P 2) 1 (x,Q 2)| ≤ F γ(P 2) 1 (x,Q 2), on the presently unknown spin–dependent structure function g γ(P 2) 1 (x,Q 2) of real and virtual photons are studied at scales Q2 ≫ P 2 where longitudinally polarized photons dominate physically relevant cross sections. In particular it is shown how to implement the physical constraints of positivity and ...

Electronic transport through domain walls in ferromagnetic nanowires:Co-existence of adiabatic and non-adiabatic spin dynamics

Field Quantization, Photons and Non-hermitean Modes

Field quantization, photons and non-Hermitean modes. Abstract Field quantization in unstable optical systems is treated by expanding the vector potential in terms of non-Hermitean (Fox-Li) modes. We define non-Hermitean modes and their adjoints in both the cavity and external regions and make use of the important bi-orthogonality relationships that exist within each mode set. We employ a standa...