Abstract: One example includes a tunable current element. The element includes a first magnetic flux component that is configured to exhibit a bias flux in response to a first control current. The bias flux can decrease relative energy barriers between discrete energy states of the tunable current element. The element also includes a second magnetic flux component that is configured to exhibit a control flux in response to a second control current. The control flux can change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states, such that the magnetic flux component is configured to generate a hysteretic current that provides a magnetic flux at an amplitude corresponding to the energy state of the tunable current element.

Abstract: One example includes a tunable current element. The element includes a first magnetic flux component that is configured to exhibit a bias flux in response to a first control current. The bias flux can decrease relative energy barriers between discrete energy states of the tunable current element. The element also includes a second magnetic flux component that is configured to exhibit a control flux in response to a second control current. The control flux can change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states, such that the magnetic flux component is configured to generate a hysteretic current that provides a magnetic flux at an amplitude corresponding to the energy state of the tunable current element.

Abstract: One example includes a magnetic flux source system that includes a tunable current element. The tunable current element includes a SQUID inductively coupled to a first control line that conducts a first control current that induces a bias flux in the SQUID to decrease relative energy barriers between discrete energy states of the tunable current element. The system also includes an inductor in a series loop with the SQUID and inductively coupled to a second control line that conducts a second control current that induces a control flux in the series loop to change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states to generate a current that provides a magnetic flux at an amplitude corresponding to the energy state of the at least one tunable current element.

Abstract: One example includes a magnetic flux source system that includes a tunable current element. The tunable current element includes a SQUID inductively coupled to a first control line that conducts a first control current that induces a bias flux in the SQUID to decrease relative energy barriers between discrete energy states of the tunable current element. The system also includes an inductor in a series loop with the SQUID and inductively coupled to a second control line that conducts a second control current that induces a control flux in the series loop to change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states to generate a current that provides a magnetic flux at an amplitude corresponding to the energy state of the at least one tunable current element.