1 Quantum coherent control of a hybrid superconducting circuit made with graphene-based van der Waals heterostructures Joel I-Jan Wang 1,†,* , Daniel Rodan-Legrain 2, † , Landry Bretheau 3 , Daniel L. Campbell 1 , Bharath Kannan 1,4 , David Kim 5 , Morten Kjaergaard 1 , Philip Krantz 1 , Gabriel O. Samach 4,5 , Fei Yan 1 , Jonilyn L. Yoder 5 , Kenji Watanabe 6 , Takashi Taniguchi 6 , Terry P. Orlando 1,4 , Simon Gustavsson 1 , Pablo Jarillo-Herrero 2,* , William D. Oliver 1,2,5,* Affiliations: 1 Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. 2 Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. 3 Laboratoire des Solides Irradiés, Ecole Polytechnique, CNRS, CEA, 91128 Palaiseau, France. 4 Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. 5 Massachusetts Institute of Technology (MIT) Lincoln Laboratory, 244 Wood Street, Lexington, MA 02421, USA. 6 Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan. † These authors contribute equally to this work. * Correspondence to: joelwang@mit.edu; pjarillo@mit.edu; william.oliver@mit.edu Abstract Quantum coherence and control is foundational to the science and engineering of quantum systems 1,2 . In van der Waals (vdW) materials, the collective coherent behavior of carriers has been probed successfully by transport measurements 3–6 . However, temporal coherence and control, as exemplified by manipulating a single quantum degree of freedom, remains to be verified. Here we demonstrate such coherence and control of a superconducting circuit incorporating graphene-based Josephson junctions. Furthermore, we show that this device can be operated as a voltage-tunable transmon qubit 7–9 , whose spectrum reflects the electronic properties of massless Dirac fermions traveling ballistically 4,5 . In addition to the potential for advancing extensible quantum computing technology, our results represent a new approach to studying vdW materials using microwave photons in coherent quantum circuits.