Localized Nanoscale Formation of Vanadyl Porphyrin\n2D MOF Nanosheets and Their Optimal Coupling to Lumped Element Superconducting\nResonators

A strategy toward\nthe realization of a quantum spin processor involves\nthe coupling of spin qubits and qudits to photons within superconducting\nresonators. To enable the realization of such hybrid architecture,\nhere we first explore the design of a chip with multiple lumped-element\nLC superconducting resonators optimized for their coupling to distinct\ntransitions of a vanadyl porphyrin electronuclear qudit. The controlled\nintegration of the vanadyl qudit onto the superconducting device,\nboth in terms of number and orientation, is then attained using the <i>in situ</i> formation of nanosheets of a 2D framework built\non the vanadyl qudit as a node. Low-temperature transmission experiments\ndemonstrate the coupling of photons in resonators with different frequencies\nto the targeted electronuclear transitions of the vanadyl qudit, also\nconfirming the control over the vanadyl qudit node orientation. The\nderived collective spin-photon couplings in the 0.3–1.6 MHz\nrange then allow to estimate enhanced, optimal, single spin photon\ncouplings up to 4 Hz.