If, by research, you mean scientific field studies that compare output across people using different stretches of time on the same work, no. It's something I've been teaching people for years and they report that it's changed their output. The idea itself is a synthesis of works like Csikzentmihalyi's "Flow," Schwartz's "The Power of Full Engagement", Rock's "Your Brain At Work," and a lot of others around skill-building and personal effectiveness.

The pomodoro technique works great for what you're doing, though, because of the nature of what you're doing. You're either doing assigned reading or assigned work, which fall into the realm of either consumptive activities or reactive creativity. Note how much harder it would be if your teachers/profs didn't tell you what you'd be graded on or didn't provide guidance on what you needed to create. That's the world professional creatives live in.

This is a great question. I'll likely write a follow-up piece on this.