Topic: The Law of Temperature Transformation

Speaker:  Prof. Jinwu Ye

Coordinates: Classroom 5104, 16:00, Friday, June 16

Abstract: Despite the special theory of relativity was discovered 120 years ago, how the temperature transforms in the theory remains unknown. This historical outstanding problem was initiated from the phenomenological thermodynamics point of view by the late giants such as Planck, Einstein, Pauli and Laue and also followed  intensively by many other people. Here we resolve this outstanding problem by using a completely different approach which starts from the fundamental quantum statistic mechanics point of view: writing a partition function  in terms of  path integral in the imaginary time at a finite temperature,then perform Lorentz transformation directly on the partition function.

For a Lorentz invariant (LI) system, we find a moving body gets hot. If the system has a finite temperature phase transition such as the electro-weak phase transition, the critical temperature drops.

We also study the effects of a finite chemical potential $ \mu \neq 0 $(which breaks the LI explicitly) and the low energy limit leading to condensed matter systems. We find any $ \mu \neq 0 $ is well defined in the co-moving frame only, but not any other frames. The temperature transformation law still holds universally for any relativistic or  non-relativistic system, but how does the critical temperature transform depends on the specific system.

Contrast to the known Unruh effects for an accelerating observer is made. Experimental detections of these effects in  condensed matter system or cold atom systems are discussed.