Thunderbolt 1&2 can technically do the throughput. One problem is your GPU can't do the resolution. The max output of the 750M (your graphics GPU chip) is 4096 x 2160 at 24Hz.
See:
http://support.apple.com/kb/SP690?viewlocale=en_US&locale=en_US
- HDMI video output
- Support for 1080p resolution at up to 60Hz
- Support for 3840-by-2160 resolution at 30Hz
- Support for 4096-by-2160 resolution at 24Hz
Apple *might* be working on a Thunderbolt 5K display that supports 4096x2160/38040x2160/1080p input and upscales it to 5K.
The power of your 750M isn't going to do much at 4096x2160 24Hz other than normal desktop apps. You can still play games at 1080p like a lot of people do on 4K displays.
Edit addition: What will be interesting, is if we will get a MacBook Pro update with GPU's that can support 5K external output...... I really really wish they'd tell us! PLEASE APPLE!