PIRSA:10110071

Is temperature the speed of time? Thermal time and the Tolman effect

Smerlak, M. (2010). Is temperature the speed of time? Thermal time and the Tolman effect. Perimeter Institute. https://pirsa.org/10110071

Smerlak, Matteo. Is temperature the speed of time? Thermal time and the Tolman effect. Perimeter Institute, Nov. 16, 2010, https://pirsa.org/10110071 

          @misc{ pirsa_10110071,
            doi = {10.48660/10110071},
            url = {https://pirsa.org/10110071},
            author = {Smerlak, Matteo},
            keywords = {Quantum Gravity},
            language = {en},
            title = {Is temperature the speed of time? Thermal time and the Tolman effect},
            publisher = {Perimeter Institute},
            year = {2010},
            month = {nov},
            note = {PIRSA:10110071 see, \url{https://pirsa.org}}
          }

Matteo Smerlak Max Planck Institute for Mathematics in the Sciences

DOI 10.48660/10110071
Collection
Talk Type Scientific Series
Subject

Abstract

Why is a vertical column of gas at thermal equilibrium slighly hotter at the bottom than a the top? My answer in this talk will be that time runs slower in a deeper gravitational potential, and temperature is nothing but the (inverse) speed of time. Specifically, I will (i) introduce Rovelli's notion of thermal time, (ii) use it to provide a "principle" characterization of thermal equilibrium in stationary spacetimes, and (iii) effortlessly derive the Tolman-Ehrenfest relation. This approach contrasts with the "constructive" accounts of thermal equilibrium in curved spacetimes given in the literature, and vindicates the time-temperature relationship cropping up in the Hawking-Unruh and Kubo-Martin-Schwinger relations.