functional integral formulation

The functional integral formulation is a way physicists describe quantum systems by considering all possible histories or configurations a system can take. Instead of focusing on a single path, it sums over every possible path, weighting each by a value related to its likelihood. This approach provides a comprehensive picture of how particles behave and interact, capturing the full range of quantum effects. It’s a powerful mathematical tool that allows for calculating probabilities and understanding complex quantum phenomena by integrating over functions or fields, rather than simple variables.