Can two Worlds (MyWorld and default World) work in the same sub scene(current subscene)?

Can I create a World in Default world(current subscene) ? I wish can use new worldA’s entitymanagerA to controll some enitties.
I worte the code, and it’s passed compile, but in the Runtime it report AssertException: srcEntity is empty(almost like that). It’s means Instantiate() use an empty entity for instance. My code like below:

Entity cube = entitymanagerA .Instantiate(generator.cubeProtoType);

The generator is from my Authoring file that is baking a prefab. I just wanna use this prefab in my new World——worldA. But the Authoring file is only attached to the default world(current subscene), how can I use this prefab(you know in editor prefab is easy to add components and materials etc.) with my own worldA?
As I know there 2 method are too difficult to use: move entity from default wolrd to new world, or create a new Entity with all by code(I don’t know how to add mesh and material to an Entity with code).

If someone know the method please tell me, thank you. And it’s better to give me a sample code about this operation. Thank you very much.

Yes or no, can or can’t? Does anyone can tell me?