Low‐temperature physics runs both hot and cold

The domain of the low‐temperature physicist now extends down as low as microdegrees Kelvin and, on the high side, up to the rather startling temperature of $108$ K. Valid claims to these two extreme regions of temperature were staked out by two papers presented at the recent 12th International Conference on Low Temperature Physics at Kyoto. In the first, P. M. Berglund, G. J. Ehnholm, R. G. Gylling, O. V. Lounasmaa and R. P. So/vik (Helsinki University of Technology) reported the successful operation of a large cryostat that has reached temperatures as low as 500 microdeg K. The system, which combines dilution refrigeration with the relatively new technique of nuclear adiabatic demagnetization, promises to open the way for physicists to study the properties of matter at temperatures an order of magnitude lower than has previously been possible.