By Dan Weil Harvard’s Prof. Summers rebuts Nobel laureate Paul Krugman, who questions whether the Fed needs to raise interest rates further. For the past year, economists Larry Summers, the star Harvard professor, and Paul Krugman, a Nobel Prize winner, have been at odds about how bad inflation is. Summers has seen it as a bigger problem than Krugman does. He has called for tighter monetary policy from the Federal Reserve than Krugman has. The dispute came up again after Krugman argued in a column last week that it might be time for the Fed to slow down its interestrate hikes. Then Summers too…