What is zero-point energy

The energy of a system of vibrating atoms, given by Equation (15.1), 

What solids are named high thermal conductivity materials  

What physical property does thermoelectric rehigeration utilise  

Thermoelectric materials used for refrigeration utilise the Peltier effect. Two thermoelectric materials are coupled by metal plates, which act as the junctions. A current passed through the circuit in one direction will heat one plate and cool the other. For refrigeration to occur, the temperature of the hot junction is maintained constant by connection to a heat sink, which may simply be a fan. Continuous cooling will occur at the cold junction. These are widely used in food and drinks coolers powered by a car battery. 

Agrawal, 1994, [NPZ] A New Family of Real Materials for Low Thermal Expansion Applications , Journal of Materials Education 16 139-165. 

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