How to disable a specific calendars notification? How can I disable the notifications for a specific calendar only? 

Example: 
I have the calendar of my girlfriend synced to my phone to know the times she is at home, working, etc. Now I get all the notifications about the events from her calendar. I want to get notifications for my calendar only, but not for hers. 

Maybe this is important too:
I am using a Davical server and sync my calendars over caldav sync.
You could use e.g. Calendar Event Reminder, and disable notifications in the default/stock calendar. With CER, you can setup reminders for each calendar separately, and even deactivate alerts for calendars you don't want to be alerted for (in your case, the "work" calendar).

The added plus is you will never miss an alert anymore, as you can configure CER to annoy you until you shut the alert of manually. I've bought the app when it was still payed, and it never let me down.

Unfortunately, I don't know of any way to do that with the native calendar -- but at least this is a free solution, though it takes an extra app :)