The vast majority—93 percent—of external funding spent by the physics department in fiscal year 2011 came from federal sources, including a number of grants from the Department of Defense, according to statistics from the Harvard Office for Sponsored Programs.

"The government is our lifeline to carrying out fundamental research," explained Physics Professor Isaac F. Silvera.

The $20.4 million of federal money spent in fiscal year 2011 represents less than a quarter of the nearly $90 million promised to Harvard physics from fifteen different federal sources over the coming years. More than one-third of that amount comes from the National Science Foundation, with the Defense Advanced Research Projects Agency (DARPA) contributing 13 percent.

Professors whose research is supported by DARPA and other military agencies said that being funded by the Department of Defense does not indicate that research will necessarily be used for warfare.

Physics Professor Gerald Gabrielse, who studies the properties of antimatter using funds from the Air Force Office of Scientific Research, said he is not aware of any immediate military implications of his work. Military agencies fund academic research to "keep an eye on" projects with potential applications in the future, he added.

Similarly, Physics Professor Amir Yacoby is working on the development of a quantum computer and sensitive magnetic field sensors for DARPA. Whereas NSF is more flexible when researchers deviate from their original research proposals, defense agencies follow the progress of research more closely, he said.

"They’re interested in the final product," Yacoby said. "They want to make sure that it’s still relevant to [their] goals."

Classified research is sometimes conducted using Defense Department funds, according to Department Chair Melissa Franklin. However, no professors interviewed for this article said they currently knew of any classified projects.

Gabrielse said he would not have accepted government funds if he believed that the research would be used in a way he deemed morally ambiguous.

But he noted that conducting research supported by the government is still a worthy endeavor.

"Defending our country is an honorable and good thing," Gabrielse said. "I regard taking government funds as a sense of trust."

In terms of total dollars spent, Physics was the third most sponsored department in the Faculty of Arts and Sciences in fiscal year 2010, after Chemistry and Chemical Biology and Molecular and Cellular Biology.

But federal funding represents a lesser proportion—86 percent—of CCB’s total expenses for the 2011 fiscal year, likely due to greater access to funding from private sources.

Chemical and biological research can have direct applications to medicine that are appealing to industry, according to Eric J. Heller, professor of physics and chemistry.

On the other hand, physics is "not an interesting place for industries to invest" because the research is more "fundamental," said Silvera.

"Physics questions generated all the gorgeous theory and some of the experiments which have made so much progress in biology and chemical biology," Heller said. "They somehow don’t get paid as much for that."

--Staff writer Radhika Jain can be reached at radhikajain@college.harvard.edu.