In situations such as phase ordering or non-equilibrium critical dynamics, the two-time autoresponse function scales as
R(t,s)approxs−1−aF2(t/s), where
a is a known exponent. For any value of the dynamical exponent
z, we argue that this dynamical scaling can be extended towards conformal invariance. Thus the scaling function
F2 is determined. This prediction is confirmed by several examples, both for
T<Tc and at
T=Tc: the two- and three-dimensional kinetic Ising model with Glauber dynamics is studied numerically, while exact results are available for the kinetic spherical model with a non-conserved order parameter, both for short-ranged and long-ranged interactions, as well as for the mean-field spherical spin glass.
The aging behavior of the random n-vector model with long-range interaction decaying as r-(d+σ) (where d is the dimensionality), is investigated by the theoretic renormalization-group approach. The system initially disordered at a high temperature is firstly quenched to the critical temperature T c and then released to an evolution with model A dynamics. The aging properties are studied by the short-time expansions. The scaling behavior of two-time response and correlation functions are obtained in a frame of the expansion in ∊ = 2σ-d. In dimensions d < 2σ, the long-time limit of the critical fluctuation dissipation ratio X∞ is calculated up to one-loop order. The simulation of X∞ is discussed.
The kinetic spherical model with long-range interactions is studied after a quench to
T<Tc or to
T=Tc. For the two-time response and correlation functions of the order-parameter as well as for composite fields such as the energy density, the ageing exponents and the corresponding scaling functions are derived. The results are compared to the predictions which follow from local scale-invariance.