Kardar-Parisi-Zhang equation with temporally correlated noise: A nonperturbative renormalization group approach

We investigate the universal behavior of the Kardar-Parisi-Zhang (KPZ) equation with temporally correlated noise. The presence of time correlations in the microscopic noise breaks the statistical tilt symmetry, or Galilean invariance, of the original KPZ equation with delta-correlated noise (denoted SR-KPZ). Thus, it is not clear whether the KPZ universality class is preserved in this case. Conflicting results exist in the literature, some advocating that it is destroyed even in the limit of infinitesimal temporal correlations, while others find that it persists up to a critical range of such correlations. Using nonperturbative and functional renormalization group techniques, we study the influence of two types of temporal correlators of the noise: a short-range one with a typical timescale tau, and a power-law one with a varying exponent theta. We show that for the short-range noise with any finite tau, the symmetries (the Galilean symmetry, and the time-reversal one in 1 + 1 dimension) are dynamically restored at large scales, such that the long-distance and long-time properties are governed by the SR-KPZ fixed point. In the presence of a power-law noise, we find that the SR-KPZ fixed point is still stable for theta below a critical value theta(th), in accordance with previous renormalization group results, while a long-range fixed point controls the critical scaling for theta > theta(th), and we evaluate the theta-dependent critical exponents at this long-range fixed point, in both 1 + 1 and 2 + 1 dimensions. While the results in 1 + 1 dimension can be compared with previous studies, no other prediction was available in 2 + 1 dimension. We finally report in 1 + 1 dimension the emergence of anomalous scaling in the long-range phase.