Abstract: A magnetic field causing a difference of energy level between different spin states in the sample can be applied, a spin transition in the material can be triggered by exposing the sample to electromagnetic radiation of an energy level corresponding to the difference in energy level between the different spin states, a sensing surface of a superconducting element can be exposed to a magnetic field of the spins in the sample, the spin transition can cause, via kinetic inductance, a change in electromagnetic waves carried by the superconducting element which can be detected. A magnetic field component normal to the sensing surface, below a certain magnetic field threshold, can be applied to favor sensitivity.

Abstract: A magnetic field causing a difference of energy level between different spin states in the sample can be applied, a spin transition in the material can be triggered by exposing the sample to electromagnetic radiation of an energy level corresponding to the difference in energy level between the different spin states, a sensing surface of a superconducting element can be exposed to a magnetic field of the spins in the sample, the spin transition can cause, via kinetic inductance, a change in electromagnetic waves carried by the superconducting element which can be detected. A magnetic field component normal to the sensing surface, below a certain magnetic field threshold, can be applied to favor sensitivity.

Abstract: Method and circuit for reading a value {circumflex over (?)}z stored in a quantum information unit (qubit) memory having a qubit frequency ?a, with a resonator defined by a resonator damping rate ?, a resonator frequency ?r, a resonator electromagnetic field characterized by ↠and â, a longitudinal coupling strength gz, an output âout and a longitudinal coupling gz{circumflex over (?)}z(â†+â). At a quantum non-demolition (QND) longitudinal modulator, periodically modulating the longitudinal coupling strength gz with a signal of amplitude {tilde over (g)}z at least three (3) times greater than the resonator damping rate ? and of frequency ?m with ?m+? resonant with ?r, wherein the longitudinal coupling strength gz varies over time (t) in accordance with gz(t)=gz+{tilde over (g)}z cos(?mt) with gz representing an average value of gz and at a QND homodyne detector, measuring the value {circumflex over (?)}z of the qubit memory from a phase reading of the output {circumflex over (?)}out.

Abstract: Method and circuit for reading a value {circumflex over (?)}z stored in a quantum information unit (qubit) memory having a qubit frequency ?a, with a resonator defined by a resonator damping rate ?, a resonator frequency ?r, a resonator electromagnetic field characterized by ↠and â, a longitudinal coupling strength gz, an output âout and a longitudinal coupling gz{circumflex over (?)}z(â†+â). At a quantum non-demolition (QND) longitudinal modulator, periodically modulating the longitudinal coupling strength gz with a signal of amplitude {tilde over (g)}z at least three (3) times greater than the resonator damping rate ? and of frequency ?m with ?m+? resonant with ?r, wherein the longitudinal coupling strength gz varies over time (t) in accordance with gz(t)=gz+{tilde over (g)}z cos(?mt) with gz representing an average value of gz and at a QND homodyne detector, measuring the value {circumflex over (?)}z of the qubit memory from a phase reading of the output {circumflex over (?)}out.