We propose this definition as the quantum of information randomness.
One ubit (unpredictable bit) has the following properties:
Its value may be either 0 or 1, both with equal probabilities.
Its value is determined by at least one unpredictable event.
One unpredictable event impedes all its predictors from knowing two of its magnitudes simultaneously: one previous state and all further transformations until its occurrence.
For example: the result of measuring the exact position of a given particle at a given time is unpredictable due to the uncertainty principle.
Estimating unpredictability of random number generators
It is possible to estimate the unpredictability of random number generators analyzing how many ubits determine the value of each output bit:
A pseudo-random number generator, implementing constant transformations to all determinants for all output bits, has an unpredictability of: 0 ubits/1 bits.
A pseudo-random number generator, seeded with 8 ubits before giving an output of 64 bits, has an unpredictability of: 8 ubits/64 bits.
A random number generator, such as a qubit in a never measured superposition state, has an unpredictability of: 1 ubits/0 bits.
A true random number generator has an unpredictability of at least: 1 ubits/1 bits.
The more ubits determine each output bit, the more unpredictable it is, being the highest unpredictability: infinite ubits/1 bits, the lowest: 0 ubits/1 bits, and the optimum for a true random number generator: 1 ubits/1 bits.
After years of research, we formulated the hypothesis, that the main source of randomness in the entire universe, is the zero-point energy. This would explain, why only hardware is able to generate true and unpredictable random numbers: any software without relationship with the zero-point energy, lacks randomness.
Zero-point energy seems to be the responsible force for moving everything everywhere: it seems to be time's creator.