Essentially all students accepted into our Department are offered financial support in the form of a graduate assistantship. (A fraction of incoming students are offered scholarships in various forms which cover salary at similar levels but with no requirement of being a TA or RA.) The graduate assistantships are either in the form of a Teaching Assistantship (TA) or a Research Assistantship (RA). A detailed description can be viewed by clicking here. A TA will help in running undergraduate labs, grading, recitation sections and such. An RA will be doing research under some professor, generally doing their own research towards a PhD. Typically, incoming students start out as TAs until they pass their Qualifying Exam, whereupon they will join some research group or start working with a particular professor as an RA. In general, it is a good idea to get some experience as a TA, but to start the RA work on your thesis as soon as is reasonable. In general, all students are covered by a graduate assistantship for their entire time at LSU.
The dollar amount of the salary depends in detail on various circumstances and the year, so no set figure can be expected or quoted. However, to give the scale, for August 2010, the median salary was $22,200 for incoming students. In addition, all tuition is covered. Since there are a wide variety of circumstances that affect the salary, the only rock solid knowledge will be the dollar amount that we quote to you in our offer letter. The policies and salaries in our Department are essentially identical to those of all other top-level Physics Departments at research Universities throughout the USA. The salaries that you earn will not make you rich, but you will live comfortably.