Decoherence Time Scale for Different Qubit Realizations

[gioialorusso]

Hi everybody,
I've searched all the internet but I can't find the answer to my question. Which are times of decoherence for different physical realization of a qubit? Like, if I use photons, or spin electron, or nuclei, or ion trap, to encode a qubit, which are times of decoherence for each?
Thank you for now,
Gioia

 

[f95toli]

It can be everything from the order of 1 fs to 1 s.
The time does not only depend on the system used, but also how it is implemented and probed so it is difficult to give any generic answers.

 

[gioialorusso]

yeah, i know it, but i have really to give some numbers for each particle, and I don't know where to find them... Hope someone has some estimation about the question. thanks for now.

 

[f95toli]

You just have to look up the relevant papers. Things move fast in this field, so what was "state of the art" a few years ago is already dated (i.e. don't bother looking in books).

Just to give you an example: superconducting qubits (which is what I am most familiar with) have gone from having a coherence time of about 10 ns to at least 10 us in just over ten years, and there has been almost one order of magnitude improvement just in the past few years due to improved sample design.

 

[gioialorusso]

I'll try to search better about optical quantum computation and ion traps. :)