  Energy fluctuation of ideal Fermi gas trapped under generic power law
potential $U=\sum_{i=1} ^d c_i |\frac{x_i}{a_i}|^{n_i}$ have been calculated in
arbitrary dimension. Energy fluctuation is scrutinized further in the
degenerate limit $\mu>> K_BT$ with the help of Sommerfeld expansion. The
dependence of energy fluctuation on dimensionality and power law potential is
studied in detail. Most importantly our general result can exactly reproduce
the recently published result regarding free and harmonically trapped ideal
Fermi gas in d=3 (S Biswas, J Mitra, S Bhattacharyya, J. Stat. Mech. P03013,
2015.)
