problem in adding quantum equations in keynote

I also meant to say as well what VikingOSX said in that simply capturing an image elsewhere of the equations and putting those images into Keynote is also a very good way to go, probably the best.

SO using an external program (such as this: http://www.mathmagic.com/product/lite.html) i.e. something dedicated like that I can imagine would give you perfect spacing and easy layout options would be much easier and provide better and faster results than any of the unicode/character-based methods.

In this case, creating the layout in Math+Magic and using the area screen capture ability of macOS (COMMAND SHIFT 4) is probably your biggest friend.

There are a number of possibilities. Apple does have a help guide here, though I am not sure if it has what you need:

About LaTeX and MathML support in Pages, Numbers, Keynote, and iBooks Author - Apple Support

I think the easiest thing is to simply copy them from a document online that uses them (and uses them as real characters, not as images) and paste them in. For example, I copied the following from here: https://en.wikipedia.org/wiki/Template:Braket

⟨ψ|Ĥ|ξ⟩

I trust you were able to see the above characters properly??? Let me know if not.

You can also grab a lot of them here:

http://xahlee.info/comp/unicode_math_operators.html

The ultimate possibility is to install the Mac's Unicode keyboard an input source by going to > System Preferences > Keyboard icon > Input Sources, and add the Unicode Hex Input and check the box to Show Input menu in menu bar.

You can then click the flag by the clock that will now be showing, and change it to your new input:

This will allow you to type unicode codes via your Mac keyboard for your Bra-Ket notation, but you'd have to look up the individual codes and then type them in.

For example:

https://www.compart.com/en/unicode/U+232A

While you are switched to Unicode Hex Input, to place U+3009 (the "decomposition" code, not the main 232A code) into your document, hold down the option key and – while holding it down – tap the four keys 3, 0, 0, and 9 in sequence. On pressing the last of the four, the character 〉 appears; you can then release the option key.

Looking up the individual codes... unless you can find a cheat sheet somewhere for the needed notation (I tried) is really a pain though. Again, I would recommend copying them from an existing page on the Internet such as a physics paper on the subject that is not a singular image or primitive PDF file, but rather a web page or more advanced PDF that let's you select characters.

Apple's equation support in Pages, Numbers, and Keynote relies on a minimalistic, compiled Blahtex translator that converts [La]TeX and MathML codes into document objects. Blahtex ignores any installed TeX implementation and all associated packages.

The links elsewhere in these threads will get you to the Blahtex PDF guide which has tables of [La]TeX characters and the commands to create them. Both \Psi and \psi are among them.

The bra and ket are specialized Dirac notation methods unique to the Physics package and you will not have access to them in Keynote, unless you generate your content outside of Keynote as a PDF (or image) and place it into Keynote.