I understand how normal logic gates operate and are implemented using digital circuits and electronics but I wad wondering how qubits are physically implemented.

In other words is a physical qubit a mechanical structure or an electronic circuit or optical circuit or something else.

There's often alot of information online about qubits and how they are different from normal bits but I have never seen any information about how they are possibly physically implemented.

  • 1
    $\begingroup$ What about Wikipedia as a start? $\endgroup$
    – Sanya
    Dec 13, 2016 at 17:48
  • $\begingroup$ I already tried Wikipedia, I didn't find it very helpful, I'm looking for a more detailed and (specific) explanation. its very easy to pull a logic gate or transistor circuit of the internet for example and begin to understand how it represents physical bits, by either having 5V across the circuit or below 3.3V. But with quantum computers I would like something in just as much depth, I understand they are abit more 'complicated', all I find on Wikipedia is a vague and very abstract explanation $\endgroup$
    – user131618
    Dec 13, 2016 at 17:59
  • $\begingroup$ Then I would write that you already did this and what exactly you are looking for into the question so people can answer you at the level you are interested in :) $\endgroup$
    – Sanya
    Dec 13, 2016 at 18:03

1 Answer 1


A qbit is no more "physical" than a normal bit. Both are measures of the information stored in an object; they are not the object itself.

In the case of a qbit, the physical thing is any object which exhibits quantum behaviors and can remain in "coherence" for a reasonably long period of time. Obviously any object exhibits some quantum behavior, but most quickly "decohere" due to thermal noise -- collisions between particles.

Just like normal-bit carrying objects can store the information in many mediums (charges in RAM, magnetic regions, on hard disks, photons over fiber optic cables, etc.) objects which store qbits also have been created from many materials. Wikipedia has a pretty nice list, but I'd point out the most interesting examples -- electrons, photons, and "quantum dots," which are very popular media for storing qbits.

Whether this qualifies as "electronic" is really up to your own definition of "electronic." However, I will point out that all modern implementations of quantum computers use a tremendous amount of electrical equipment to maintain these qbits in their coherent state, and to help them interact with each other in the desired ways. This is akin to how, in fiber optics, all of the data is transmitted with photons, but a tremendous amount of electrical equipment is used to get it into that form in the first place!


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