A tunable quantum qubit circuit comprising: a plurality of interconnected Josephson tunneling junctions sculpted in-situ on-chip, wherein each Josephson tunneling junction comprises a pair of high temperature superconductors separated by an active region having a controlled charge density; a capacitive-coupled control gate operatively coupled to the Josephson tunneling junctions and configured to simultaneously modulate energy levels of the Josephson tunneling junctions; and independent control gates operatively coupled to the Josephson tunneling junctions, wherein the independent control gates are reconfigurable on-the-fly by an operator.