Showing deciseconds in the homescreen I am interested in a clock app that in addition to seconds also shows deciseconds.

I searched and could not find one yet. Is there any widget for Android that shows deciseconds (like this: 11:51:32.1)?
It's not possible to create a widget that updates that often, because it will suck your battery really quickly. There are many stopwatch apps available in the Play Store. Many of them have millisecond or decisecond accuracy, but I'm not aware of any that have an associated widget. 

These kind of high precision timers should only be needed on a case-to-case basis, so it's not worth it for them to be on the homescreen.