Coherent Control of an Exfoliated NbSe₂ Homojunction Qubit in a Three-Dimensional Cavity

Functionalizing quantum devices to extend their range of applications is an extremely active area of research. One of the most promising approaches is to replace aluminum with functional materials. Within this context, van der Waals (vdW) superconductors are ideal candidates because they could enable the integration of their unique properties into qubits. In this work, we present a qubit whose Josephson junction is fabricated from exfoliated NbSe2 using a lithography-free process. Our device exhibits a relaxation time T1 = 275 ±7 ns as well as coherence times T*2 = 136 ± 31 ns and T Echo2 = 203 ± 16 ns. Our work demonstrates the feasibility of integrating vdW superconductors into quantum technologies and represents a first step toward applying quantum non-demolition photon-detection protocols to the challenging field of dark matter searches.