Tunable coupler for making a controllable coupling to at least a first qubit (801, 1501), comprising: - a first constant coupling element (803, 1506), and - a tunable coupling element (804, 1509), there being a coupling between said first (803, 1506) and tunable (804, 1509) coupling elements; wherein: - said first constant coupling element (803, 1506) forms a first non-galvanic coupling interface to at least said first qubit (801, 1501) at a first extremity of said first constant coupling element (803, 1506) distant from said tunable coupling element (804, 1509), for a strong coupling due to a close proximity of the first constant coupling element (803, 1506) and said first qubit (801, 1501) at said first non-galvanic coupling interface, and - said tunable coupling element (804, 1509) is located adjacent to a second non-galvanic coupling interface formed to a further circuit element (802, 805, 1507) at a second extremity of said first constant coupling element (803, 1506), there being a coupling between said tunable coupling element (804, 1509) and said further circuit element (802, 805, 1507) and a strong coupling due to a close proximity of the first constant coupling element (803, 1506) and said further circuit element (802, 805, 1507) at said second non-galvanic coupling interface; wherein said tunable coupling element (804, 1509) is configured to be tuned in order to adapt a coupling strength of the coupling between the tunable coupling element (804, 1509) and the first constant coupling element (803, 1506) and a coupling strength of the coupling between the tunable coupling element (804, 1509) and the further circuit element (802, 805, 1507); and wherein said further circuit element (802, 805, 1507) is a second constant coupling (805, 1507) element or a second qubit. - a first constant coupling element (803, 1506), and - a tunable coupling element (804, 1509), there being a coupling between said first (803, 1506) and tunable (804, 1509) coupling elements; - said first constant coupling element (803, 1506) forms a first non-galvanic coupling interface to at least said first qubit (801, 1501) at a first extremity of said first constant coupling element (803, 1506) distant from said tunable coupling element (804, 1509), for a strong coupling due to a close proximity of the first constant coupling element (803, 1506) and said first qubit (801, 1501) at said first non-galvanic coupling interface, and - said tunable coupling element (804, 1509) is located adjacent to a second non-galvanic coupling interface formed to a further circuit element (802, 805, 1507) at a second extremity of said first constant coupling element (803, 1506), there being a coupling between said tunable coupling element (804, 1509) and said further circuit element (802, 805, 1507) and a strong coupling due to a close proximity of the first constant coupling element (803, 1506) and said further circuit element (802, 805, 1507) at said second non-galvanic coupling interface; wherein said tunable coupling element (804, 1509) is configured to be tuned in order to adapt a coupling strength of the coupling between the tunable coupling element (804, 1509) and the first constant coupling element (803, 1506) and a coupling strength of the coupling between the tunable coupling element (804, 1509) and the further circuit element (802, 805, 1507); and wherein said further circuit element (802, 805, 1507) is a second constant coupling (805, 1507) element or a second qubit.