Hadamard matrices of order 28m, 36m and 44m

Hadamard Matrices of Order 28m, 36m and 44m

We show that if four suitable matrices of order m exist then there are Hadamard matrices of order 28 m, 36 m, and 44 m. In particular we show that Hadamard matrices of orders 14(q + 1), 18(q + 1), and 22(q + 1) exist when q is a prime power and q = l(mod 4). Also we show that if n is the order of a conference matrix there is an Hadamard matrix of order 4mn. As a consequence there are Hadamard m...

Hadamard matrices of order 32

Two Hadamard matrices are considered equivalent if one is obtained from the other by a sequence of operations involving row or column permutations or negations. We complete the classification of Hadamard matrices of order 32. It turns out that there are exactly 13710027 such matrices up to equivalence. AMS Subject Classification: 05B20, 05B05, 05B30.

Hadamard matrices of order 764 exist

Two Hadamard matrices of order 764 of Goethals– Seidel type are constructed. Recall that a Hadamard matrix of order m is a {±1}-matrix A of size m × m such that AA T = mI m , where T denotes the transpose and I m the identity matrix. We refer the reader to one of [2, 4] for the survey of known results about Hadamard matrices. In our previous note [1], written about 13 years ago, we listed 17 in...

Jacket matrices constructed from Hadamard matrices and generalized Hadamard matrices

Mutually unbiased bases and Hadamard matrices of order six

We report on a search for mutually unbiased bases MUBs in six dimensions. We find only triplets of MUBs, and thus do not come close to the theoretical upper bound 7. However, we point out that the natural habitat for sets of MUBs is the set of all complex Hadamard matrices of the given order, and we introduce a natural notion of distance between bases in Hilbert space. This allows us to draw a ...