  We present a finite-dimensional version of the quantum model for the stock
market proposed in [C. Zhang and L. Huang, A quantum model for the stock
market, Physica A 389(2010) 5769]. Our approach is an attempt to make this
model consistent with the discrete nature of the stock price and is based on
the mathematical formalism used in the case of the quantum systems with
finite-dimensional Hilbert space. The rate of return is a discrete variable
corresponding to the coordinate in the case of quantum systems, and the
operator of the conjugate variable describing the trend of the stock return is
defined in terms of the finite Fourier transform. The stock return in
equilibrium is described by a finite Gaussian function, and the time evolution
of the stock price, directly related to the rate of return, is obtained by
numerically solving a Schrodinger type equation.
