PhD in theoretical physics after dropping out of PhD program in Engineering? I am applying to US universities for PhD in theoretical physics (for Fall 2015). I was earlier an engineering undergraduate student from a reputed college in Asia with GPA of around 8.0 (on a scale of 10). Due to my research experience during undergraduate, I got scholarship to do my PhD in Europe at one of the top-30 universities in the world. But after two years into the graduate program and publishing one journal paper, I realized that I was only doing numerical methods which did not really suit me as I always wanted to do rigorous math and discover new physics. So I left this program (in good standing) to pursue theoretical physics research. 

Immediately, I joined the topmost physics institute in my country for research in string theory, cosmology, general relativity. Within a year, I was able to produce three publications in top high energy physics journals like the Journal of High Energy Physics (JHEP) with my collaborators, who are well-known. So these collaborators have provided me good recommendations as well. Additionally, I have good GRE and GRE Physics scores.

My question is how an unconventional profile like mine will be seen by graduate admission committees at good US Universities. Would my engineering background (especially dropping out part) and lack of official physics coursework put me at disadvantage ? How much my four publications would help me in the process ?

Thanks
The only problem I can see with cases like yours is that some people may look at the file and think "This is someone who can't finish what they start."  It is essential for you to communicate in the statement of purpose why you left the old program and why you believe you will complete a new one.