  We investigate the effect of hydrodynamic fluctuations on the rapidity
decorrelations of anisotropic flow in high-energy nuclear collisions using a
(3+1)-dimensional integrated dynamical model. The integrated dynamical model
consists of twisted initial conditions, fluctuating hydrodynamics, and hadronic
cascades on an event-by-event basis. To understand the rapidity decorrelation,
we analyze the factorization ratio in the longitudinal direction. Comparing the
factorization ratios between fluctuating hydrodynamics and ordinary viscous
hydrodynamics, we find a sizable effect of hydrodynamic fluctuations on
rapidity decorrelations. We also propose to calculate the Legendre coefficients
of the flow magnitude and the event-plane angle to understand the decorrelation
of anisotropic flow in the longitudinal direction.
