How to reach the Max Planck Institute for Physics (Werner Heisenberg Institute): 

please have a look at 
http://www.mpp.mpg.de/english/metanavi/contact/directions01/index.html

a short description is also given below:

* from the airport, it is convenient to take the Lufthansa Bus to Munich North (Nordfriedhof)    
http://www.airportbus-muenchen.de/cms/en/home/   
From there take the underground U6 towards Garching and get off at "Studentenstadt" (2 stops).  
From Studentenstadt it is a 5mins walk (continue city-outwards towards a big crossroads, 
turn right there, then you will see the Institute).    

* from the Munich main train station: take any subway line going to Marienplatz (2 stops), 
there change to U6 towards Forschungszentrum Garching and get off at "Studentenstadt".
From Studentenstadt it is a 5mins walk (see above).

* Further infos about public transport can also be found at 
http://www.mpp.mpg.de/english/guests/mvv/index.html