Families of complex Hadamard matrices
نویسندگان
چکیده
منابع مشابه
Families of Complex Hadamard Matrices
What is the dimension of a smooth family of complex Hadamard matrices including the Fourier matrix? We address this problem with a power series expansion. Studying all dimensions up to 100 we find that the first order result is misleading unless the dimension is 6, or a power of a prime. In general the answer depends critically on the prime number decomposition of the dimension. Our results sug...
متن کاملParametrizing complex Hadamard matrices
Abstract. The purpose of this paper is to introduce new parametric families of complex Hadamard matrices in two different ways. First, we prove that every real Hadamard matrix of order N ≥ 4 admits an affine orbit. This settles a recent open problem of Tadej and Życzkowski [11], who asked whether a real Hadamard matrix can be isolated among complex ones. In particular, we apply our construction...
متن کاملTrades in complex Hadamard matrices
A trade in a complex Hadamard matrix is a set of entries which can be changed to obtain a different complex Hadamard matrix. We show that in a real Hadamard matrix of order n all trades contain at least n entries. We call a trade rectangular if it consists of a submatrix that can be multiplied by some scalar c 6= 1 to obtain another complex Hadamard matrix. We give a characterisation of rectang...
متن کاملThe excess of complex Hadamard matrices
A complex Hadamard matrix, C, of order n has elements 1, -1, i, i and satisfies CC* = nIn where C* denotes the conjugate transpose of C. Let C = [cij] be a complex Hadamard matrix of order n. S(C) = ∑ cij is called the sum of C. 0(C) = │S(C)│ is called the excess of C. We study the excess of complex Hadamard matrices. As an application many real Hadamard matrices of large and maximal excess are...
متن کاملThe 2-transitive complex Hadamard matrices
We determine all possibilities for a complex Hadamard matrix H admitting an automorphism group which permutes 2-transitively the rows of H. Our proof of this result relies on the classification theorem for finite 2-transitive permutation groups, and thereby also on the classification of finite simple groups.
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ژورنال
عنوان ژورنال: Linear Algebra and its Applications
سال: 2013
ISSN: 0024-3795
DOI: 10.1016/j.laa.2012.10.029