Critical exponents in microgravity
Abstract
Critical exponents describe the dependence of thermodynamic quantities near to phase trasitions as function of the difference between the actual temperature and the critial temperature. These quantities are, e.g., the density, the pressure, the heat capacities, the magnetization, and others. It is an amazing fact that critical exponents depend neither on the underlying matter model nor on the interaction between the constituents. This is a result which has been derived with the help of renormalization group theory. Phase trasitions are accompanied by an increase of fluctuations near the phase transition. Critical exponets also exist for Bose-Einsten condensates. One important aspect is that there is a remarkably strong influence of a gravitational field on these quantities and on the phase transition. The gravitational field induces an anisotropy in the systems. Under these circumstances the universality will be destroyed. Accordingly, for high precision tests or measurements one has to place the devices in a microgravity environment. In this contribution the theoretical as well as experimental state of the art of measurements of critical exponents will be reviewed. Emphasis is laid on the issue of measuring critical exponents for Bose-Einstein condensates in gravity and gravity-free environment.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E2088L