Don't be confuse my friend,Page rank is basically an algorithm generated by google.It is a numerical representation of any domain.The algorithm may be applied to any collection of entities with reciprocal quotations and references.Google calculates a page's importance from the votes cast for it.
If you talking about the position of your domain in search engine than it totally depends on the back links of your site.all that because of Indexation and Crawl Frequency.
In Indexation is simply related on relevant search engine index.It is nothing but getting optimum pages in whatever the search engine.The variation of ranking is the effect of Indexation.Here are few points for batter indexation:
Tamplets with fresh navigation
Rewriting lacklustre titles and meta tags
Relevant Authority Backlinks
Crawl Frequency is simply refers that how many times(How frequently) the search engine crawel the perticular content or the site.As per simple logic of frequency the perticular site or content is upgraded,it will crawled more effectively and effciently.Parameters of links and domain authority also palys important role for frequency...