PIRSA:11070012

What Happens When Entropy Decreases

APA

Aguirre, A. (2011). What Happens When Entropy Decreases. Perimeter Institute. https://pirsa.org/11070012

MLA

Aguirre, Anthony. What Happens When Entropy Decreases. Perimeter Institute, Jul. 16, 2011, https://pirsa.org/11070012

BibTex

          @misc{ pirsa_PIRSA:11070012,
            doi = {10.48660/11070012},
            url = {https://pirsa.org/11070012},
            author = {Aguirre, Anthony},
            keywords = {Cosmology},
            language = {en},
            title = {What Happens When Entropy Decreases},
            publisher = {Perimeter Institute},
            year = {2011},
            month = {jul},
            note = {PIRSA:11070012 see, \url{https://pirsa.org}}
          }
          

Anthony Aguirre University of California, Santa Cruz

Abstract

Closed systems never evolve to lower entropy states -- except when they do, which is if one waits a time that is exponential in the entropy change. Thus macroscopic decreases in entropy are 'never' observed. Yet in cosmology there are eternal systems in which downward entropy fluctuations of any magnitude eventually happen. What is the nature of such fluctuations? I will argue that these can be understood in a simple and general way that sheds light on our understanding of various interesting cosmological processes such as bubble nucleation, black/white hole formation, eternal stochastic inflation, Boltzmann brain formation, and other processes.