Ernesto Estrada

Ernesto Estrada (born 2 May 1966) is a Cuban-Spanish scientist. He is the Chair in Complexity Science, Full Professor at the Department of Mathematics and Statistics, and a member of the Institute of Complex Systems of the University of Strathclyde, Glasgow, United Kingdom. He is known by his contributions in different disciplines including chemistry, and the mathematics and physics of Complex Systems.

Estrada was born in the city of Sancti Spiritus, in the central region of Cuba. Since the age of 11 he studied in a school which specialized in exact sciences. He later studied for a technical degree as an analytical chemist in a technological institute in Havana. At the age of 18 he presented his first scientific paper in an international congress together with his mentor, Dr. Jose F. Fernandez-Bertran. The paper was about the detection of polyatomic anions in matrices of NaCl using infrared spectroscopy. Between 1985 and 1990, he studied chemical sciences at the Central University of Las Villas in Santa Clara, Cuba, where he obtained his degree in only 4 of the 5 years established for the program. In the first years after graduation, Estrada investigated the synthesis and spectroscopic characterization of new organic molecules with biological activity. This research introduced him to the world of computational chemistry due to the requirement of using efficient methods to design biologically active molecules. In 1997, he obtained his Ph.D in Chemistry under the direction of Prof. Luis A. Montero Cabrera on the topic of "Graph Theory Applied to Molecular Design". By this time, Estrada had published 8 scientific papers in major chemistry journals.

After completing his Ph.D., Estrada spent some time as post-doctoral research at the University of Valencia, Spain working with Prof. Jorge Galvez and at the Lisa-Meitner Institute for Computational Quantum Chemistry, Hebrew University of Jerusalem with Prof. David Avnir. In 2000, he officially emigrated to Spain where he obtained a fellowship at the University of Santiago de Compostela. Between 2002 and 2003, Estrada worked as a scientist at the Safety and Environmental Assurance Centre, Unilever in Colworth, U.K. He then obtained a position as "Ramon y Cajal" researcher at the University of Santiago de Compostela, Spain. Since 2008, Estrada occupies the newly created Chair in Complexity Science at the University of Strathclyde and has published more than 160 papers, 10 book Chapters and 2 books. He is a Cuban and Spanish citizen, resident in Scotland, U.K.

Estrada has been a major contributor in the area of study of complex network, where he has developed several approaches to investigate the structure and dynamics of such systems. An index introduced by him in 1999 to characterise the degree of folding of proteins, and then generalised to the study of complex networks in 2005, has eventually became the Estrada index of a graph or network, and it is the subject of intensive research in mathematics and other fields. Estrada is also known in the field of spectral graph theory where he has introduced several approaches to characterise the organizational architecture of complex networks, such as the "subgraph centrality", "communicability", "spectral scaling", "golden spectral graphs", etc.

Estrada is also known in the area of Mathematical Chemistry, in particular to the development and use of molecular descriptors based on the use of Graph Theory. He is known for the introduction of several approaches in this field, such as the Topological Sub-Structural Molecular Design (TOPS-MODE) approach, and the generalization of topological indices.

In 2007, Estrada received the prize as Outstanding Scientist from the International Academy of Mathematical Chemistry. The prize recognizes his valuable contributions in developing and applying graph theory to solve problems in many interdisciplinary areas, such as chemistry, physics, biology, ecology and technology. In 2014 Estrada received the prestigious Royal Society Wolfson Research Merit Award of the Royal Society of London, which recognises "scientists of outstanding achievement and potential".

Estrada has been visiting Professor at the Statistical and Applied Mathematical Sciences Institute in North Carolina, USA, the Centre of Mathematical Research in Guanajuato, Mexico, the Quantititative Methods and Theory Institute and the Department of Mathematics and Computer Science at Emory University in Atlanta, USA.

Since 2013 Estrada is the Editor-in-Chief of the Journal of Complex Networks published by Oxford University Press.

• Estrada, E.; Hatano, N. Returnability in complex directed networks (digraphs). Linear Algebra and its Applications 430, 2009, 1886-1896.
• Estrada, E.; Hatano, N. Communicability in Complex Networks. Physical Review E 77, 2008, 036111.
• Estrada, E. Topological structural classes of complex networks. Physical Review E 75, 2007, 016103.
• Estrada, E. Spectral scaling and good expansion properties in complex networks. Europhysics Letters 73, 2006, 649-655.
• Estrada, E.; Rodríguez-Velázquez, J. A. Subgraph centrality in complex networks. Physical Review E 71, 2005, 056103.
• Estrada, E. Generalization of topological indices. Chemical Physics Letters 336, 2001, 248-252.
• Estrada, E. Characterization of the folding degree of proteins. Bioinformatics 18, 2002, 697-704.