While, vim is very powerful by himself, the strong user base of vim lead to a huge number of plugins, there is almost one for your every need. Assuming computational physicists use fortran90(+) for coding and latex most often then not, here is a list of vim plugins that will make their life a lot easier.
Disclaimer: This is not an extensive list, this is just my choice, that I worked with and I love.
General Plugins: First thing first: some language independent plugins:
On my experience, for day to day coding with vim, this 6 plugins are indispensable, and once you get used to with them, these will increase your efficiency a lot.
Plugin for Fortran:
For using them, one need to tweak the .vimrc a lot. I am pasting my working .vimrc. Feel free to modify them for your own use.
- Pathogen : This must be the first plugin one should install before doing anything else. This makes managing the rest of the plugins "super-easy".
Alternative: Absolute must, no alternative. - Commentary: Commenting a number of lines in vim is pain. With no plugins, one possiblly can do ":a,b/^/^!/g" for fortran or ":a,b/^/^%/g" for latex. Get rid of this with this minimal extension! You can do only 3 things with this, and possibly those are all you will ever need.
Alternative: nerd-commentor (used this for long, much more options, those I have hardly used.). - Project: While working in a multifile code, this is an absolute-must. Once configured, it will give you a treeview of files in your project for easy navigation.

Vim Screenshot with Project Plugin. One project expanded
Alternative: IDE is a good alternative, it is an extension of Project. - Nerdtree: Explores full filesystem.
- Taglist: This is a sourcecode browser. "Provides an overview of the structure of source code files and allows you to efficiently browse through source code files for different programming languages."

Vim Screenshot with taglist plugin with a f90 code - Ultisnips: "UltiSnips is a mature template library for Vim. Thus you can write code snippets once then refer to them by short words and make Vim expand them.": The developer of the Ultisnips, Marc Weber says it all.
NB: There are atleast 2 Ultisnips, one by SirVer and other, that is linked here, is by Marc. Marc's is a fork or SirVer. Both are good, but I will recommend Marc's. If for nothing else, the big point is Marc is very approachable and helping.
On my experience, for day to day coding with vim, this 6 plugins are indispensable, and once you get used to with them, these will increase your efficiency a lot.
Plugin for Fortran:
- codecomplete: Actually, we don't have much plugins for fortran. But this one (along with fortran.vim, that ships with vim itself) is very helpful. It completes the structure of fortran code.
- Vim-Latex: This is a ultimate plugin. It has huge number of functionalities, and hence, a steep learning (and forgetting) curve. But if you get used to with it, it makes writing latex code a pleasure.
For using them, one need to tweak the .vimrc a lot. I am pasting my working .vimrc. Feel free to modify them for your own use.