Construction, classification and parametrization of complex Hadamard matrices

F Szöllősi - arXiv preprint arXiv:1110.5590, 2011 - arxiv.org
The intended purpose of this work is to provide the reader with a comprehensive, state-of-
the art presentation of the theory of complex Hadamard matrices, or at least report on the …

Almost Perfect mutually unbiased bases that are sparse

A Kumar, S Maitra, S Roy - Journal of Statistical Theory and Practice, 2024 - Springer
Selected ideas of statistical designs are exploited in this paper in constructions related to
Mutually Unbiased Bases (MUBs). In dimension d, MUBs are a collection of orthonormal …

Uniformity in association schemes and coherent configurations: cometric Q-antipodal schemes and linked systems

ER Van Dam, WJ Martin, M Muzychuk - Journal of Combinatorial Theory …, 2013 - Elsevier
Inspired by some intriguing examples, we study uniform association schemes and uniform
coherent configurations, including cometric Q-antipodal association schemes. After a review …

Mutually Unbiased Bases in Composite Dimensions--A Review

D McNulty, S Weigert - arXiv preprint arXiv:2410.23997, 2024 - arxiv.org
Maximal sets of mutually unbiased bases are useful throughout quantum physics, both in a
foundational context and for applications. To date, it remains unknown if complete sets of …

Almost Hadamard matrices: general theory and examples

T Banica, I Nechita, K Życzkowski - Open Systems & Information …, 2012 - World Scientific
We develop a general theory of almost Hadamard matrices. These are by definition the
matrices H∈ MN (ℝ) having the property that is orthogonal, and is a local maximum of the 1 …

Further Constructions of AMUBs for Non-prime power Composite Dimensions

A Kumar, S Maitra - arXiv preprint arXiv:2402.04231, 2024 - arxiv.org
Construction of a large class of Mutually Unbiased Bases (MUBs) for non-prime power
composite dimensions ($ d= k\times s $) is a long standing open problem, which leads to …

Complex Hadamard matrices and equiangular tight frames

F Szöllősi - Linear Algebra and its Applications, 2013 - Elsevier
In this paper, we give a new construction of parametric families of complex Hadamard
matrices of square orders, and connect them to equiangular tight frames. The results …

[HTML][HTML] Balancedly splittable Hadamard matrices

H Kharaghani, S Suda - Discrete Mathematics, 2019 - Elsevier
Balancedly splittable Hadamard matrices are introduced and studied. A connection is made
to the Hadamard diagonalizable strongly regular graphs, maximal equiangular lines set, and …

Unbiased complex Hadamard matrices and bases

D Best, H Kharaghani - Cryptography and Communications, 2010 - Springer
We introduce mutually unbiased complex Hadamard (MUCH) matrices and show that the
number of MUCH matrices of order 2 n, n odd, is at most 2 and the bound is attained for n …

Linked systems of symmetric group divisible designs

H Kharaghani, S Suda - Journal of Algebraic Combinatorics, 2018 - Springer
We introduce the concept of linked systems of symmetric group divisible designs. The
connection with association schemes is established, and as a consequence we obtain an …