  The coherent dynamics of a quantum mechanical two-level system passing
through an anti-crossing of two energy levels can give rise to
Landau-Zener-St\"uckelberg-Majorana (LZSM) interference. LZSM interference
spectroscopy has proven to be a fruitful tool to investigate charge noise and
charge decoherence in semiconductor quantum dots (QDs). Recently, bilayer
graphene has developed as a promising platform to host highly tunable QDs
potentially useful for hosting spin and valley qubits. So far, in this system
no coherent oscillations have been observed and little is known about charge
noise in this material. Here, we report coherent charge oscillations and
$T_2^*$ charge decoherence times in a bilayer graphene double QD. The charge
decoherence times are measured independently using LZSM interference and photon
assisted tunneling. Both techniques yield $T_2^*$ average values in the range
of 400 to 500 ps. The observation of charge coherence allows to study the
origin and spectral distribution of charge noise in future experiments.
