graduate admissions - Moving to a different PhD program in the United States

I have been admitted to a Math PhD program in US. The school is ranked in the top 60-80 range. I started school this August. I'm, however, considering the possibility of re-applying to a different program, based on the following reasons:

1. 
   

   My undergraduate background is in physics, economics and mathematics. I'm a late comer to the subject (mathematics); therefore, my application wasn't as competitive as it could have been if I had studied the subject for the full four years. This was reflected in the number of acceptances/rejections that I received.

   
   


2. 
   

   I would like to move to a department that focuses on inter-disciplinary research. Unfortunately, such options aren't available at my current department.

   
   



3. 
   

   I may have an issue picking an adviser in the future. I will skip the details over here.

   
   


4. 
   

   My job prospects would be quite bleak in academia (Math) if I choose to stay over here.

   
   

Based on a combination of academic and non-academic reasons, I believe I would like to take another shot at applying to different schools. I’d appreciate if you could put this issue in perspective by commenting on:

1. 
   
   

   Whether this is a possibility in the system in place in the US? Are such issues frowned upon?

   
   


2. 
   

   How does generally view such issues? What’s the overall perception of academics in math departments?

   
   


3. 
   

   What would be the best way to tackle this issue? For example, what would be the best time to discuss this issue with faculty? I don’t want to antagonize anyone, but, at the same time, I’d like to discuss my aforementioned case with someone in the future so I can consider the possibility of re-applying.

   
   

Any suggestions would be appreciated.