Can I contact a professor who works on my same work
You do not &quot;need&quot; to contact them. The fact that your work was on a university website does not mean that anyone has seen it.
Unless there are subtler clues that they just copied your work, you should treat that work as completely independent of yours.
If you email them, do not express any doubts about their honesty, etc. This would in-any-case terminally alienate them. Rather, say that you have similar interests, as visible in your thesis, which actually obtains some similar results.
Do NOT make any remarks about how your thesis was on-line for a year, and &quot;should have been cited&quot;, etc. Things don't really work that way.
Again, most often it's not that people are cheating, but that they have similar ideas, due to similar contexts...