A method for determining a characteristic bit-flip time of a
quantum qubit in a superconducting
quantum device, comprises the following operations: a) initializing an idling time and a probability density function (P) of bit-flip time testing parameters (θ) according to a first probability distribution (p), said bit-flip testing time parameters (θ) comprising at least a decreasing lifetime rate (Γz) said probability density function (P) of bit-flip time testing parameters (θ) being a Poisson distribution with the probability of observing a
total measurement outcome y = ∑i yi being given by (see formula (I)), where p0 / 1 is a function comprising a component of the type e-Γzt, said probability density function of bit-flip time testing parameters (θ) being stored on a grid of values for the bit-flip time testing parameters (θ), b) preparing a physical
qubit in a chosen state, c) idling for a duration derived from the idling time, d) obtaining a bit-flip measurement (y) by reading the state of the physical
qubit, e) updating the probability
distribution function of bit-flip time testing parameters (p(θ)) using the measurement (y) of operation d), the idling time of operation c), and with the formula p(θ) = p(θ)p(y|θ,t) / p(y,t), f) calculating an estimated
information gain for each possible measurement time using the updated probability
distribution function of bit-flip time testing parameters (p(θ)) of operation e), from the
information gain equal to the difference between the Shannon entropy of the probability
distribution function of the decreasing lifetime rate (p(Γz)) and the Shannon entropy of the
conditional probability distribution function of the decreasing lifetime rate knowing the measurement of operation d) and the idling time (p(Γz|(y,t)), or an estimated information flow with the information flow which is a function of the
information gain and the idling time, g) defining a new idling time as the
value of time which maximizes the estimated information
gain or the estimated information flow of operation f), h) Returning the bit-flip testing time parameters (θ) if p(θ) satisfies a return condition derived from the evolution of the decreasing lifetime rate (Γz), and / or comparison with a return threshold, and else repeating steps b) to g) with the idling time of operation g) and the probability distribution function (p) of bit-flip time testing parameters (θ) of operation e).