Steven Chu (born February 28, 1948) is an American physicist and a former government official. He is known for his research at Bell Labs and Stanford University regarding the cooling and trapping of atoms with laser light, for which he won the Nobel Prize in Physics in 1997, along with his scientific colleagues Claude Cohen-Tannoudji and William Daniel Phillips. Chu served as the 12th United States Secretary of Energy from 2009 to 2013. At the time of his appointment as Energy Secretary, Chu was a professor of physics and molecular and cellular biology at the University of California, Berkeley, and the director of the Lawrence Berkeley National Laboratory, where his research was concerned primarily with the study of biological systems at the single molecule level. Color photo, signed, also includes newspaper article.|||Length: 11 in (27.9 cm) Width: 8 1/2 in (21.6 cm)|諾貝爾物理獎得主朱棣文照片簽名|