Weizsacker energy of unitary Fermi gas in a harmonic trap

The universal method of construction of the rigorous lower bounds to the Weizsacker energy is presented. We study a few-fermion systemat the unitarity. Upper and lower bounds to the density functional theory(DFT) ground state energy within the local density approximation (LDA) aregiven. Therigorous lower bounds to the accuracy of the method are derived.