The grand partition function for a Bose gas is given by::formula_1where each term in the product corresponds to a particular energy εi , gi is the number of states with energy εi , "z " is the absolute activity (or "fugacity"), which may also be expressed in terms of the chemical potential μ by defining::formula_2and β defined as::formula_3where "k " is Boltzmann's constant and "T " is the temperature.
i , gi is the number of states with energy εi , "z " is the absolute activity (or «fugacity»), which may also be expressed in terms of the chemical potential μ by defining:где каждый множитель в произведении соответствует определённой энергии εi , количество состояний с этой энергией обозначено gi , а "z " - это абсолютная активность («летучесть», ), которая также может быть выражена через химический потенциал:: formula_1and β defined as:: formula_2where "k " is Boltzmann's constant and "T " is the temperature.