Many systems obey simple, linear rules: If you pull twice as hard on a spring, it stretches twice as far. However, when we introduce very large forces or complicated interactions, that linear rule ...

The Nature Index 2025 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...

The nonlinear susceptibility is a measure of a material's nonlinear response to an applied electric field. It determines the strength of the nonlinear effects and is related to the crystal's symmetry ...