Norms of Randomized Circulant Matrices

We investigate two-sided bounds for operator norms of random matrices with unhomogenous independent entries. We formulate a lower bound for Rademacher matrices and conjecture that it may be reversed up to a universal constant. We show that our conjecture holds up to $\log\log n$ factor for randomized $n\times n$ circulant matrices and double logarithm may be eliminated under some mild additional assumptions on the coefficients.