Zobrazeno 1 - 10
of 25
pro vyhledávání: '"Dragomir Ž. Ðoković"'
Autor:
N. A. Balonin, Dragomir Ž. Ðoković
Publikováno v:
Information and Control Systems. :2-10
Introduction: There are just a few known methods for the construction of symmetric C-matrices, due to the lack of a universal structure for them. This obstruction is fundamental, in addition, the structure of C-matrices with a double border is incomp
Publikováno v:
Special Matrices, Vol 7, Iss 1, Pp 127-141 (2019)
Our main objective is to show that the computational methods, developed previously to search for difference families in cyclic groups, can be fully extended to the more general case of arbitrary finite abelian groups. In particular the power spectral
Publikováno v:
Special Matrices, Vol 6, Iss 1, Pp 11-22 (2018)
We continue our systematic search for symmetric Hadamard matrices based on the so called propus construction. In a previous paper this search covered the orders $4v$ with odd $v\le41$. In this paper we cover the cases $v=43,45,47,49,51$. The odd inte
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d6a9031baa9407828ead8a559a75aa31
http://arxiv.org/abs/1710.03037
http://arxiv.org/abs/1710.03037
Autor:
Dragomir Ž. Ðoković, Lin Chen
Publikováno v:
Physical Review A. 94
We show that a bipartite quantum state of rank four is distillable if its partial transpose has at least one negative eigenvalue; that is, the state is a non-positive-partial transpose (NPT). For this purpose we prove that if the partial transpose of
Publikováno v:
Journal of Combinatorial Designs. 21:24-35
Turyn-type sequences, , are quadruples of -sequences , with lengths , respectively, where the sum of the nonperiodic autocorrelation functions of and twice that of is a δ-function (i.e., vanishes everywhere except at 0). Turyn-type sequences are kno
Publikováno v:
Special Matrices, Vol 3, Iss 1 (2015)
We construct new symmetric Hadamard matrices of orders $92,116$, and $172$. While the existence of those of order $92$ was known since 1978, the orders $116$ and $172$ are new. Our construction is based on a recent new combinatorial array discovered
Autor:
Dragomir Ž. Ðoković
Publikováno v:
Open Physics, Vol 9, Iss 1, Pp 65-70 (2011)
By modifying the method of Bruß and Peres, we construct two new families of entangled two qutrit states. For all density matrices ρ in these families we have ρ ij = 0 for i + j odd. The first family depends on 27 independent real parameters and in
Autor:
Dragomir Ž. Ðoković
Publikováno v:
International Journal of Combinatorics. 2010:1-21
Base sequences BS ( 𝑛 + 1 , 𝑛 ) are quadruples of { ± 1 } -sequences ( 𝐴 ; 𝐵 ; 𝐶 ; 𝐷 ) , with A and B of length 𝑛 + 1 and C and D of length n, such that the sum of their nonperiodic autocor-relation functions is a 𝛿 -function
Publikováno v:
King's College London
Let F be an algebraically closed field of characteristic different from 2. We show that every nonsingular skew-symmetric n by n matrix X over F is orthogonally similar to a bidiagonal skew-symmetric matrix. In the singular case one has to allow some
Autor:
Dragomir Ž. Ðoković
Publikováno v:
Linear Algebra and its Applications. 437:2680-2682
Mirsky proved that, for the existence of a complex matrix with given eigenvalues and diagonal entries, the obvious necessary condition is also sufficient. We generalize this theorem to matrices over any field and provide a short proof. Moreover, we s