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The distance between the eigenvalues of Hermitian matrices [PDF]

Proceedings of the American Mathematical Society, 1986
It is shown that the minmax principle of Ky Fan leads to a quick simple derivation of a recent inequality of V. S. Sunder giving a lower bound for the spectral distance between two Hermitian matrices. This brings out a striking parallel between this result and an earlier known upper bound for the spectral distance due to L. Mirsky.
openaire   +2 more sources

Beyond the Edge: Charge‐Transfer Excitons in Organic Donor‐Acceptor Cocrystals

Advanced Functional Materials, EarlyView.
Complex excitonic landscapes in acene–perfluoroacene cocrystals are unveiled by polarization‐resolved optical spectroscopy and many‐body theory. This systematic study of a prototypical model system for weakly interacting donor–acceptor compounds challenges common views of charge‐transfer excitons, providing a refined conceptual framework for ...
Sebastian Anhäuser, Ana M. Valencia, Sergei I. Ivlev, Marc Zeplichal, Andreas Terfort, Caterina Cocchi, Gregor Witte   +6 more
wiley   +1 more source

Eigenvalue monotonicity of $q$-Laplacians of trees along a poset

, 2018
Let $T$ be a tree on $n$ vertices with $q$-Laplacian $L_{T}^{q}$. Let $GTS_n$ be the generalized tree shift poset on the set of unlabelled trees with $n$ vertices.
Nagar, Mukesh Kumar
core   +1 more source

An Eigenvalue Characterization of Antipodal Distance-Regular Graphs [PDF]

The Electronic Journal of Combinatorics, 1997
Let $G$ be a regular (connected) graph with $n$ vertices and $d+1$ distinct eigenvalues. As a main result, it is shown that $G$ is an $r$-antipodal distance-regular graph if and only if the distance graph $G_d$ is constituted by disjoint copies of the complete graph $K_r$, with $r$ satisfying an expression in terms of $n$ and the distinct eigenvalues.
openaire   +3 more sources

Spherical Two-Distance Sets and Eigenvalues of Signed Graphs

Combinatorica, 2023
AbstractWe study the problem of determining the maximum size of a spherical two-distance set with two fixed angles (one acute and one obtuse) in high dimensions. Let $$N_{\alpha ,\beta }(d)$$ N α ,
Jiang, Zilin, Tidor, Jonathan, Yao, Yuan, Zhang, Shengtong, Zhao, Yufei   +4 more
openaire   +3 more sources

Purpose‐Adaptable Reinforced 3D Hyaluronic‐Acid Based Platform to Study Pathomechanisms of the Central Nervous System

Advanced Healthcare Materials, EarlyView.
Platform system to create biofabricated 3D spinal cord tissue models: Combining high resolution PCL fiber placement, a customized, hyaluronic acid‐based hydrogel, two cell types (spinal cord neurons and astrocytes) together with three distinct laminin isoforms allow the formation of functional cell–cell network interactions.
Nicoletta Murenu, Esra Tuerker, Anna‐Lena Wiessler, Jessica Faber, Ievgenii Liashenko, Jeanette Weigelt, Jörg Tessmar, Paul D. Dalton, Sibylle Jablonka, Mateo S. Andrade Mier, Carmen Villmann, Silvia Budday, Natascha Schaefer   +12 more
wiley   +1 more source

ON THE GENERALIZED DISTANCE EIGENVALUES OF GRAPHS

Matematički Vesnik
Summary: For a simple connected graph \(G\), the generalized distance matrix \(D_{\alpha}(G)\) is defined as \(D_{\alpha}(G)=\alpha Tr(G)+(1-\alpha)D(G)\), \(0\leq \alpha\leq 1\). The largest eigenvalue of \(D_{\alpha}(G)\) is called the generalized distance spectral radius or \(D_{\alpha}\)-spectral radius of \(G\). In this paper, we obtain some upper
Alhevaz, A., Baghipur, M., Ganie, H. A., Das, K. C.   +3 more
openaire   +2 more sources

Distance-regular graphs where the distance-d graph has fewer distinct eigenvalues

Linear Algebra and its Applications, 2015
Let the Kneser graph $K$ of a distance-regular graph $ $ be the graph on the same vertex set as $ $, where two vertices are adjacent when they have maximal distance in $ $. We study the situation where the Bose-Mesner algebra of $ $ is not generated by the adjacency matrix of $K$.
Fiol Mora, Miquel Àngel, Brouwer, Andries   +1 more
openaire   +4 more sources

Gapless Superconductivity From Extremely Dilute Magnetic Disorder in 2H‐NbSe2‐xSx

Advanced Materials, EarlyView.
We demonstrate that 2H‐NbSe2‐xSx hosts gapless superconductivity at unexpectedly low magnetic impurity concentrations. Combining STM, Bogoliubovde Gennes simulations, DFT, and quasiparticle interference, we comprehensively study the development of gapless behavior and show that SeS substitution reshapes the band structure, enhances nesting, and drives ...
Jose Antonio Moreno, Mercè Roig, Víctor Barrena, Edwin Herrera, Alberto M. Ruiz, Samuel Mañas‐Valero, Antón Fente, Anita Smeets, Jazmín Aragón, Yanina Fasano, Beilun Wu, Maria N. Gastiasoro, Eugenio Coronado, José J. Baldoví, Brian M. Andersen, Isabel Guillamón, Hermann Suderow   +16 more
wiley   +1 more source

On the Sum of Distance Laplacian Eigenvalues of Graphs

Tamkang Journal of Mathematics, 2021
Let $G$ be a connected graph with $n$ vertices, $m$ edges and having diameter $d$. The distance Laplacian matrix $D^{L}$ is defined as $D^L=$Diag$(Tr)-D$, where Diag$(Tr)$ is the diagonal matrix of vertex transmissions and $D$ is the distance matrix of $G$.
Pirzada, Shariefuddin, Khan, Saleem
openaire   +3 more sources