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We exactly evaluate the entanglement of a six vertex and a nine vertex graph states which correspond to non ''two-colorable'' graphs. The upper bound of entanglement for five vertices ring graph state is improved to 2.9275, less than upper…

Quantum Physics · Physics 2009-09-10 Xiao-yu Chen , Li-zhen Jiang

Recent work at the intersection of formal language theory and graph theory has explored graph grammars for graph modeling. However, existing models and formalisms can only operate on homogeneous (i.e., untyped or unattributed) graphs. We…

Social and Information Networks · Computer Science 2023-01-06 Satyaki Sikdar , Neil Shah , Tim Weninger

We investigate two notions of saturation for partial planar embeddings of maximal planar graphs. Let $G = (V, E) $ be a vertex-labeled maximal planar graph on $ n $ vertices, which by definition has $3n - 6$ edges. We say that a labeled…

Combinatorics · Mathematics 2024-12-10 Alexander Clifton , Dániel G. Simon

The Connected Vertex Cover problem is to decide if a graph G has a vertex cover of size at most $k$ that induces a connected subgraph of $G$. This is a well-studied problem, known to be NP-complete for restricted graph classes, and, in…

Data Structures and Algorithms · Computer Science 2018-07-06 Matthew Johnson , Giacomo Paesani , Daniel Paulusma

A graph $G$ has maximal local edge-connectivity $k$ if the maximum number of edge-disjoint paths between every pair of distinct vertices $x$ and $y$ is at most $k$. We prove Brooks-type theorems for $k$-connected graphs with maximal local…

Combinatorics · Mathematics 2022-03-07 Pierre Aboulker , Nick Brettell , Frédéric Havet , Dániel Marx , Nicolas Trotignon

For a given $\varepsilon > 0$, we say that a graph $G$ is $\varepsilon$-flexibly $k$-choosable if the following holds: for any assignment $L$ of color lists of size $k$ on $V(G)$, if a preferred color from a list is requested at any set $R$…

Combinatorics · Mathematics 2023-06-13 Peter Bradshaw , Tomáš Masařík , Ladislav Stacho

Standard Bell inequalities hold when distant parties are not allowed to communicate. Barrett et al. found correlations from Pauli measurements on certain network graphs refute a local hidden variable (LHV) description even allowing some…

Quantum Physics · Physics 2023-07-19 Uta Isabella Meyer , Frédéric Grosshans , Damian Markham

We obtain an essential spectral gap for $n$-dimensional convex co-compact hyperbolic manifolds with the dimension $\delta$ of the limit set close to $(n-1)/2$. The size of the gap is expressed using the additive energy of stereographic…

Spectral Theory · Mathematics 2016-08-23 Semyon Dyatlov , Joshua Zahl

We introduce exactly solvable gapless quantum systems in $d$ dimensions that support symmetry protected topological (SPT) edge modes. Our construction leads to long-range entangled, critical points or phases that can be interpreted as…

Strongly Correlated Electrons · Physics 2017-12-08 Thomas Scaffidi , Daniel E. Parker , Romain Vasseur

Let $(X,E_X)$ and $(V,E_V)$ be finite connected graphs without loops. We assume that $V$ has two distinguished vertices $a,b$ and an automorphism $\gamma$ which exchanges $a$ and~$b$. The $V$-edge substitution of $X$ is the graph $X[V]$…

Combinatorics · Mathematics 2025-08-21 Thomas Hirschler , Wolfgang Woess

Nonlinear spectral gaps with respect to uniformly convex normed spaces are shown to satisfy a spectral calculus inequality that establishes their decay along Cesaro averages. Nonlinear spectral gaps of graphs are also shown to behave…

Metric Geometry · Mathematics 2014-09-30 Manor Mendel , Assaf Naor

We study gaps in the spectra of the adjacency matrices of large finite cubic graphs. It is known that the gap intervals $(2 \sqrt{2},3)$ and $[-3,-2)$ achieved in cubic Ramanujan graphs and line graphs are maximal. We give constraints on…

Mathematical Physics · Physics 2021-01-18 Alicia J. Kollár , Peter Sarnak

We analyze a class of quantum spin models defined on half-spaces in the $d$-dimensional hypercubic lattice bounded by a hyperplane with inward unit normal vector $m\in\mathbb{R}^d$. The family of models was previously introduced as the…

Mathematical Physics · Physics 2016-08-25 Michael Bishop , Bruno Nachtergaele , Amanda Young

Due to the limited resources and the scale of the graphs in modern datasets, we often get to observe a sampled subgraph of a larger original graph of interest, whether it is the worldwide web that has been crawled or social connections that…

Machine Learning · Computer Science 2018-12-04 Ashish Khetan , Harshay Shah , Sewoong Oh

We discuss (1+1)d gapless phases with non-invertible global symmetries, also referred to as categorical symmetries. This includes gapless phases showing properties analogous to gapped symmetry protected topological (SPT) phases, known as…

Strongly Correlated Electrons · Physics 2025-11-26 Lakshya Bhardwaj , Daniel Pajer , Sakura Schafer-Nameki , Alison Warman

Spectral analysis connects graph structure to the eigenvalues and eigenvectors of associated matrices. Much of spectral graph theory descends directly from spectral geometry, the study of differentiable manifolds through the spectra of…

Social and Information Networks · Computer Science 2019-05-24 Kun Dong , Austin R. Benson , David Bindel

We construct generalized Hofstadter models that possess "color-entangled" flat bands and study interacting many-body states in such bands. For a system with periodic boundary conditions and appropriate interactions, there exist gapped…

Strongly Correlated Electrons · Physics 2015-01-29 Ying-Hai Wu , J. K. Jain , Kai Sun

Quantum entanglement marks a definitive feature of topological states. However, the entanglement spectrum remains insufficiently explored for topological states without a bulk energy gap. Using a combination of field theory and numerical…

Strongly Correlated Electrons · Physics 2024-07-16 Xue-Jia Yu , Sheng Yang , Hai-Qing Lin , Shao-Kai Jian

The Spectral Excess Theorem (SPET) for distance-regular graphs states that a regular (connected) graph is distance-regular if and only if its spectral-excess equals its average excess. Recently, some local or global approaches to the SPET…

Spectral Theory · Mathematics 2012-05-29 M. A. Fiol

When analyzing weighted networks using spectral embedding, a judicious transformation of the edge weights may produce better results. To formalize this idea, we consider the asymptotic behavior of spectral embedding for different…

Machine Learning · Statistics 2023-01-23 Ian Gallagher , Andrew Jones , Anna Bertiger , Carey Priebe , Patrick Rubin-Delanchy