Research objectives essay

Hello,
I am writing the research objectives essay for my application (the same will be sent to different universities). The arguments I aspire to for the PhD are things like AdS/CFT and those things related to better understand non-perturbative field theories. On the other hand I have actually never studied well these things till now.
Do you think it is more convenient for me to write a quite general essay, describing my "tastes" in theoretical physics, or to insert also a specific part in which i cite ads/cft etc..?
I think the second alternative might be effective if I addressed it to a particular research group or person, but in my case it should be better to remain more generic, also because I don't have really profound statements to write about this penchant..

Thank you!

Do not write about things you don't understand. Do write about things you are interested in and would like to pursue.

If you start writing *** like, "I want to prove that all possible string theories are really the same," but your history shows you've only taken 2 physics classes no one will take you seriously. Well, at least I wouldn't

Are you talking about your statement of purpose? If so, this is more general than a "research objectives" essay. Your research objectives are just one part of this essay. However when writing about your research objectives, I would recommend a little of the general and a little of the specific. Talk about your general interest in theoretical physics and if you can, include very specific examples that show your aptitude in this area (classes you took and did well in, theoretical research that you have already been involved in if there is any, or anything that you undertook independently that shows initiative and skill). Then, mention a few particular research groups you are interested in working with at the University you are applying to (of course this section changes slightly in each essay for each different school). If you have a particular interest in a certain subject, say so, and say why it interests you, and what leads you to believe that you want to study this area in grad school.

If you are interested in some specific parts like ads/ctf, you can mention it in your statement, that you are going to work on these areas in future, even if you haven't had extensive studies in those areas.

Thank you all for your answers.
@grae313: I have to write an only essay which is called "research objectives", it has to do with the fulbright program. Their fellowships are referred to many areas of study (in particular, the fellowship I have to do with is for almost all the fields of graduation..). Because of this they set the application process in a way common for everybody, and a part like the "research objectives" essay is perhaps more thought for more practical areas than mine.

Anyway, I decided not to mention any specific argument but just to explain the kind of things I aspire to do in theoretical physics.

Anyone know of a DL master's in theology/religion in which the coursework consists of personal essay-type papers and assignments rather than research-based papers? In other words, where the writing is more original, subjective-based, personal, rather than objective and based on/citing what others have written about the subject?