The birth-death process is a special case of continuous- time Markov process where the states represent the current size of a population and where the transitions are limited to births and deaths. Birth-death processes have many applications in demography, queueing theory, performance engineering, or in biology, for example to study the evolution of bacteria. When a birth occurs, the process goes from state n to n+1. When a death occurs, the process goes from state n to state n-1. The process is specified by birth rates and death rates.