In statistical mechanics and quantum field theory, a dangerously irrelevant operator (or dangerous irrelevant operator) is an operator which is irrelevant at a renormalization group fixed point, yet affects the infrared (IR) physics significantly (e.g.
In statistical mechanics and quantum field theory, a dangerous irrelevant operator (DIO) is an operator that appears unimportant at a specific point in the renormalization process but significantly influences infrared physics.