Laureate of the 2013 Nobel Prize in Chemistry Michael Levitt attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Staffan Normark, permanent secretary of the Royal Swedish Academy of Sciences, holds the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

(From left to right) Laureates of the 2013 Nobel Prize in Economics Robert J Shiller, Lars Peter Hansen and Eugene F Fama attend the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureate of the 2013 Nobel Prize in Chemistry Martin Karplus attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

(From left to right) Laureates of the 2013 Nobel Prize in Chemistry Arieh Warshelin, Michael Levitt and Martin Karplus attend the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureate of the 2013 Nobel Prize in Chemistry Arieh Warshelin attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureate of the 2013 Nobel Prize in Economics Lars Peter Hansen attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureates of the 2013 Nobel Prize in Physics, Chemistry and Economics attend the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureate of the 2013 Nobel Prize in Physics Francois Englert attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureates of the 2013 Nobel Prize in Physics Peter Higgs (L) and Francois Englert attend the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureate of the 2013 Nobel Prize in Economics Robert J Shiller attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureate of the 2013 Nobel Prize in Economics Eugene F Fama attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)

Laureate of the 2013 Nobel Prize in Physics Peter Higgs attends the press conference of winners of Nobel Prize in Economics, Chemistry and Physics in Stockholm, Sweden, Dec. 7, 2013. (Xinhua/Shi Tiansheng)