We study ultrasmall Josephson junctions using the coherent picture to describe the pair dynamics and the semiclassical approach for the quasiparticles. We find that the dynamics depends crucially on the ratio of the superconducting gap energy \ensuremath{\Delta}(T) to the charging energy e2/2C. The pair ``Bloch oscillations'' can be practically observed when 2\ensuremath{\Delta}(T)>e2/2C; for 2\ensuremath{\Delta}(T)e2/2C the Idc/e oscillations due to quasiparticle tunneling can be observed. We discuss under what conditions the I-V characteristic will be S-shaped, exhibiting both oscillations at different values of the current.
We show that the three-qubit entanglement classes, (0) null, (1) separable $A\text{\ensuremath{-}}B\text{\ensuremath{-}}C$, (2a) biseparable $A\text{\ensuremath{-}}BC$, (2b) biseparable $B\text{\ensuremath{-}}CA$, (2c) biseparable $C\text{\ensuremath{-}}AB$, (3) W, and (4) Greenberger-Horne-Zeilinger, correspond respectively to ranks 0, 1, 2a, 2b, 2c, 3, and 4 of a Freudenthal triple system defined over the Jordan algebra $\mathbb{C}\ensuremath{\bigoplus}\mathbb{C}\ensuremath{\bigoplus}\mathbb{C}$. We also compute the corresponding stochastic local operations and classical communication orbits.