Evolutionary algorithm for the Physical Travelling Salesman Problem
Have a look at this survey on crossover operators for TSP

It gives you the history of development on this area as well.

List of operators covered:


Partially Mapped Crossover (PMX) [Goldberg, 1985]
Order Crossover (OX) [Davis, 1985] 
Edge Crossover (EX) [Whitley, 1989]
Subtour Exchange Crossover (SXX) [Yamamura, 1992] 
Edge Exchange Crossover (EXX) [Maekawa, 1996]
Edge Assembly Crossover (EAX) [Nagata, 1997]
Partition Crossover (PX) [Whitley, 2009]