Contrast between spin and valley degrees of freedom

Dependence of effective mass on spin and valley degrees of freedom.

We measure the effective mass (m) of interacting two-dimensional electrons confined to an AlAs quantum well while we change the conduction-band valley occupation and the spin polarization via the application of strain and magnetic field, respectively. Compared to its band value, m is enhanced unless the electrons are fully valley- and spin-polarized. Incidentally, in the fully spin- and valley-...

Coupling between internal spin dynamics and external degrees of freedom in the presence of colored noise.

We observe asymmetric transition rates between Zeeman levels (spin flips) of magnetically trapped atoms. The asymmetry strongly depends on the spectral shape of an applied noise. This effect follows from the interplay between the internal states of the atoms and their external degrees of freedom, where different trapped levels experience different potentials. Such insight may prove useful for c...

Interplay between the lattice and spin degrees of freedom in (Sr1â‹TMxCax)3Ru2O7

Periodic Orbit Theory including Spin Degrees of Freedom *

We summarize recent developments of the semiclassical description of shell effects in finite fermion systems with explicit inclusion of spin degrees of freedom, in particluar in the presence of spin-orbit interactions. We present a new approach that makes use of spin coherent states and a correspondingly enlarged classical phase space. Taking suitable limits, we can recover some of the earlier ...

Effective Hamiltonian for Excitons with Spin Degrees of Freedom

Starting from the conventional electron-hole Hamiltonian Heh, we derive an effective Hamiltonian H̃1s for 1s excitons with spin degrees of freedom. The Hamiltonian describes optical processes close to the exciton resonance for the case of weak excitation. We show that straightforward bosonization of Heh does not give the correct form of H̃1s, which we obtain by a projection onto the subspace span...