Boltzmann factor

The Boltzmann factor of any energy $U$ is defined by the negative exponential of the ratio of the energy to the thermal energy Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle kT} :

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle f(U)= \exp\left(-\frac{U}{k_BT}\right) }