Logic gates are basic digital elements for computers. We build up thermal
logic gates that can perform similar operations as their electronic
counterparts. The thermal logic gates are based on the nonlinear lattices,
which exhibit very intriguing phenomena due to their temperature dependent
power spectra. We demonstrate that phonons, the heat carriers, can be also used
to carry information and processed accordingly. The possibility of nanoscale
experiment is discussed.Comment: 5 pages, 5 figures. To appear in Phys. Rev. Let