quenches

Quenches refer to processes in which a system experiences a rapid change in temperature or other external parameters, taking it out of equilibrium much faster than it can adjust. The term is used across disciplines, from materials science to quantum physics, to describe how systems respond to sudden perturbations and how they relax toward new states.

In materials science, quenching typically means heating a metal to a high temperature and then rapidly cooling it to “lock in” a particular microstructure. Common quench media include water, oil, or air. The quench rate strongly influences the resulting phases, such as the formation of martensite in steel, which increases hardness but can also raise brittleness and residual stress. Quenching is often followed by tempering or annealing to modify properties like toughness and strength.

In quantum physics, a quantum quench denotes a sudden change in a parameter of a system’s Hamiltonian, such as interaction strength or external field. This abrupt switch drives the system out of equilibrium and initiates unitary evolution under the new Hamiltonian. Researchers study how observables like correlation functions and order parameters evolve, looking for relaxation, thermalization, or the emergence of non-thermal steady states. Experimental platforms include ultracold atoms in optical lattices and trapped ions, where quenches probe many-body dynamics, prethermalization, and related phenomena.

Other contexts of quenching include rapid cooling in glass formation and certain chemical processes where temperature changes are used to control phase transitions. Across fields, the effectiveness and consequences of a quench depend on factors such as the rate, pathway, and material or system-specific properties, influencing applications from metallurgy to quantum simulation.