Inverse parabolic problem with initial data by a single measurement

We consider initial boundary value problems with the homogeneous Neumann boundary condition. Given an initial value, we establish the uniqueness in determining a spatially varying coefficient of zeroth-order term by a single measurement of Dirichlet data on an arbitrarily chosen subboundary. The uniqueness holds in a subdomain where the initial value is positive, provided that it is sufficiently smooth which is specified by decay rates of the Fourier coefficients. The key idea is the reduction to an inverse elliptic problem and relies on elliptic Carleman estimates.