A superconducting system comprising: a first qubit system comprising a first qubit; a second qubit system remote from the first qubit system and comprising a second qubit; a tunable bus-mediated coupler disposed between the first qubit and the second qubit, the tunable bus-mediated coupler comprising: a first port coupled to a first end of a Josephson junction through a first quarter-wave transmission line resonator, the first port being coupled to the first qubit; a second port coupled to a second end of the Josephson junction through a second quarter-wave transmission line resonator, the second port being coupled to the second qubit; a first termination inductor coupled between the first resonator and the Josephson junction on a first end and ground on a second end, and a second termination inductor coupled between the second resonator and the Josephson junction on a first end and ground on a second end, wherein the first termination inductor, the Josephson junction and the second termination inductor form an RF-SQUID; a bias inductor inductively coupled to one of the first termination inductor and the second termination inductor, wherein an amount of current through the bias inductor controls the coupling strength between the first and the second qubit; and a controller that controls an amount of current through the bias inductor inductively coupled to one of the first and the second termination inductors to control the inductance of the Josephson junction between a low inductance state to provide strong coupling between the first qubit and the second qubit and a high inductance state to provide isolation between the first qubit and the second qubit. a first qubit system comprising a first qubit; a second qubit system remote from the first qubit system and comprising a second qubit; a tunable bus-mediated coupler disposed between the first qubit and the second qubit, the tunable bus-mediated coupler comprising: a first port coupled to a first end of a Josephson junction through a first quarter-wave transmission line resonator, the first port being coupled to the first qubit; a second port coupled to a second end of the Josephson junction through a second quarter-wave transmission line resonator, the second port being coupled to the second qubit; a first termination inductor coupled between the first resonator and the Josephson junction on a first end and ground on a second end, and a second termination inductor coupled between the second resonator and the Josephson junction on a first end and ground on a second end, wherein the first termination inductor, the Josephson junction and the second termination inductor form an RF-SQUID; a first port coupled to a first end of a Josephson junction through a first quarter-wave transmission line resonator, the first port being coupled to the first qubit; a second port coupled to a second end of the Josephson junction through a second quarter-wave transmission line resonator, the second port being coupled to the second qubit; a first termination inductor coupled between the first resonator and the Josephson junction on a first end and ground on a second end, and a second termination inductor coupled between the second resonator and the Josephson junction on a first end and ground on a second end, wherein the first termination inductor, the Josephson junction and the second termination inductor form an RF-SQUID; a bias inductor inductively coupled to one of the first termination inductor and the second termination inductor, wherein an amount of current through the bias inductor controls the coupling strength between the first and the second qubit; and a controller that controls an amount of current through the bias inductor inductively coupled to one of the first and the second termination inductors to control the inductance of the Josephson junction between a low inductance state to provide strong coupling between the first qubit and the second qubit and a high inductance state to provide isolation between the first qubit and the second qubit.