  Pauli blockade is a fundamental quantum phenomenon that also serves as a
powerful tool for qubit manipulation and read-out. While most systems exhibit a
simple even-odd pattern of double-dot Pauli spin blockade due to the preferred
singlet pairing of spins, the additional valley degree of freedom offered by
bilayer graphene greatly alters this pattern. Inspecting bias-triangle
measurements at double-dot charge degeneracies with up to four electrons in
each dot reveals a much richer double-dot Pauli blockade catalogue with both
spin and/or valley blockade. In addition, we use single-dot Kondo effect
measurements to substantiate our understanding of the three- and four-particle
state spectra by analyzing their magnetic field dependence. With high
controllability and reported long valley- and spin-relaxation times, bilayer
graphene is a rising platform for hosting semiconductor quantum dot qubits. A
thorough understanding of state spectra is crucial for qubit design and
manipulation, and the rich Pauli blockade catalogue provides an abundance of
novel qubit operational possibilities and opportunities to explore intriguing
spin and valley physics.
