I have been making conscious early-stage efforts to wrap my head around quantum computing. As Shohini Ghose explains in her TED video, it is a future class of computing, about as different to current computing as a candle was to a light-bulb. Quantum computing emerged because classical computing reached its physical limitations, and further miniaturization was not possible with the same technology.
A brief expose of my understanding; Quantum computing goes beyond the electron into its subcomponents. Qbits (quantum bits) are these subcomponents and are what enable quantum computing. They have both positive and negative charges (or spins), that is deciphered by using a quantum decoder. These bits are in an eternal "Schrodinger's cat" state, i.e in a superposition of charges. Unlike typical bits that we use to encode information, qbits are never in just one of the charged states; they are in fact somewhere in the middle. Their existence on the spectrum is revealed in probabilities, i.e 80% probability charge 1/2 and 20% is -1/2. Expected value calculations don't mean anything here, but when you choose to "observe" them, they choose a state to show themselves in. The probability density function represents the frequency distribution of their choices.
Qbits choosing a state is well explained by Heisenberg's uncertainty principle, which says that you cannot observe both location and momentum at the same time, only one. For large objects, both are infinitesimally the same, but observing one facet essentially squashes the other at the quantum scale. If you keep location, you lose the information of velocity and vice versa. Similarly, when you observe qbits they possess both charge states, but observing forces the qbit to manifest one of its states.
In the 'jerk' of computational evolution, now a single qbit (significantly smaller than an electron already) doesn't hold not only a 0 or a 1, but everything in between. It can encode so much more information, though it does require specialized tech to read the qbit and force redundancy to avoid encoding errors (which are more frequent in quantum computers). So 4 traditional bits can hold one out of sixteen possible states (1/16 of 0000 to 1111) while four qbits can simultaneously hold all sixteen states and choose to show up as one when measured.
This seems curiously similar to how humans store information associatively rather than deterministically. We may forget a memory because it occurred 16 years ago, but a song or a walk through a familiar neighborhood or a text from someone unlocks that memory and it becomes available. Memory champions use this to their advantage by constructing a quirky tapestry of a story to hold information, and they including sight, smell, sound and sensation to aid retrieval. The more things you associate with the memory, the easier retrieval becomes.
Could associations act as probabilistic filters to our quantum memory? Maybe our memory is associative and not deterministic because we work at the quantum scale. Quantum computing could unlock huge advances in human cognition.
Sources:
Qbit diagram - https://www.austinchronicle.com/screens/2019-04-19/quantum-computing-101-a-beginners-guide-to-the-mind-bending-new-technology/