Emil Prodan
YOU?
Author Swipe
View article: Invariant measures on the transversal hull of cone semigroups and some applications
Invariant measures on the transversal hull of cone semigroups and some applications Open
Let $\LL_{\bf v}\subset \Z^D$ be a suitable cone semigroup and $\A_{\bf v}$ its reduced semigroup $C^*$-algebra. In this paper, we compute the $\LL_{\bf v}$-invariant measures in the transversal hull of the semigroup $\LL_{\bf v}$ that exh…
View article: On Frustration-Free Quantum Spin Models
On Frustration-Free Quantum Spin Models Open
The goal of our work is to characterize the landscape of the frustration-free quantum spin models over the Cayley graph of a finitely generated group $G$. This is achieved by establishing $G$-equivariant morphisms from the partially ordere…
View article: A $C^\ast$-algebraic view on the interaction of real- and reciprocal space topology in skyrmion crystals
A $C^\ast$-algebraic view on the interaction of real- and reciprocal space topology in skyrmion crystals Open
Understanding the interaction of real- and reciprocal space topology in skyrmion crystals is an open problem. We approach it from the viewpoint of C^\ast -algebras and calculate all admissible Chern numbers of a strongly coupled tight-…
View article: A $C^\ast$-algebraic view on the interaction of real- and reciprocal space topology in skyrmion crystals
A $C^\ast$-algebraic view on the interaction of real- and reciprocal space topology in skyrmion crystals Open
Understanding the interaction of real- and reciprocal space topology in skyrmion crystals is an open problem. We approach it from the viewpoint of C^\ast -algebras and calculate all admissible Chern numbers of a strongly coupled tight-…
View article: Topological Dynamics of Synthetic Molecules
Topological Dynamics of Synthetic Molecules Open
We study the dynamics of synthetic molecules whose architectures are generated by space transformations from a point group acting on seed resonators. We show that the dynamical matrix of any such molecule can be reproduced as the left regu…
View article: A space-adiabatic approach for bulk-defect correspondences in lattice models of topological insulators
A space-adiabatic approach for bulk-defect correspondences in lattice models of topological insulators Open
In space-adiabatic approaches one can approximate Hamiltonians that are modulated slowly in space by phase-space functions that depend on position and momentum. In this paper, we establish a rigorous relation between this approach and the …
View article: C*-framework for higher-order bulk-boundary correspondences
C*-framework for higher-order bulk-boundary correspondences Open
A typical crystal is a finite piece of a material which may be invariant under some point symmetry group. If it is a so-called intrinsic higher-order topological insulator or superconductor, then it displays boundary modes at hinges or cor…
View article: Pumping with symmetry
Pumping with symmetry Open
Re-configurable materials and meta-materials can jump between space symmetry classes during their deformations. Here, we introduce the concept of singular symmetry enhancement, which refers to an abrupt jump to a higher symmetry class acco…
View article: Unified topological characterization of electronic states in spin textures from noncommutative <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>K</mml:mi></mml:math>-theory
Unified topological characterization of electronic states in spin textures from noncommutative -theory Open
The nontrivial topology of spin systems such as skyrmions in real space can promote complex electronic states. Here, we provide a general viewpoint at the emergence of topological spectral gaps in spin systems based on the methods of nonco…
View article: Classifying the Dynamics of Architected Materials by Groupoid Methods
Classifying the Dynamics of Architected Materials by Groupoid Methods Open
We consider synthetic materials consisting of self-coupled identical resonators carrying classical internal degrees of freedom. The architecture of such material is specified by the positions and orientations of the resonators. Our goal is…
View article: Noncommutative geometry in physics
Noncommutative geometry in physics Open
This talk is an introduction to ideas of non-commutative geometry and star products. We will discuss consequences for physics in two different settings: quantum field theories and astrophysics. In case of quantum field theory, we will disc…
View article: Smart patterning for topological pumping of elastic surface waves
Smart patterning for topological pumping of elastic surface waves Open
Topological pumping allows waves to navigate a sample undisturbed by disorders and defects. We demonstrate this phenomenon with elastic surface waves by strategically patterning an elastic surface to create a synthetic dimension. The surfa…
View article: Pumping with Symmetry
Pumping with Symmetry Open
Re-configurable materials and meta-materials can jump between space symmetry classes during their deformations. Here, we introduce the concept of singular symmetry enhancement, which refers to an abrupt jump to a higher symmetry class acco…
View article: Converging Periodic Boundary Conditions and Detection of Topological Gaps on Regular Hyperbolic Tessellations
Converging Periodic Boundary Conditions and Detection of Topological Gaps on Regular Hyperbolic Tessellations Open
Tessellations of the hyperbolic spaces by regular polygons are becoming popular because they support discrete quantum and classical models displaying unique spectral and topological characteristics. Resolving the true bulk spectra and the …
View article: Smart patterning for topological pumping of elastic surface waves
Smart patterning for topological pumping of elastic surface waves Open
Topological pumping supplies a robust mechanism to steer waves across a sample without being affected by disorders and defects. For the first time, we demonstrate the pumping of elastic surface waves, achieved by a smart patterning of a su…
View article: Cyclic cocycles and quantized pairings in materials science
Cyclic cocycles and quantized pairings in materials science Open
The pairings between the cyclic cohomologies and the K-theories of separable $C^\ast$-algebras supply topological invariants that often relate to physical response coefficients of materials. Using three numerical simulations, we exemplify …
View article: Spectral and Combinatorial Aspects of Cayley-Crystals
Spectral and Combinatorial Aspects of Cayley-Crystals Open
Owing to their interesting spectral properties, the synthetic crystals over lattices other than regular Euclidean lattices, such as hyperbolic and fractal ones, have attracted renewed attention, especially from materials and meta-materials…
View article: Quantum versus Population Dynamics over Cayley Graphs
Quantum versus Population Dynamics over Cayley Graphs Open
Consider a graph whose vertices are populated by identical objects, together with an algorithm for the time-evolution of the number of objects placed at each of the vertices. The discrete dynamics of these objects can be observed and studi…
View article: Revealing Topology in Metals using Experimental Protocols Inspired by K-Theory
Revealing Topology in Metals using Experimental Protocols Inspired by K-Theory Open
Topological metals are special conducting materials with gapless band structures and nontrivial edge-localized resonances, whose discovery has proved elusive because the traditional topological classification methods require (possibly inco…
View article: Topological Spectral Bands with Frieze Groups
Topological Spectral Bands with Frieze Groups Open
Frieze groups are discrete subgroups of the full group of isometries of a flat strip. We investigate here the dynamics of specific architected materials generated by acting with a frieze group on a collection of self-coupling seed resonato…
View article: Revealing Topology in Metals using Experimental Protocols Inspired by $K$-Theory
Revealing Topology in Metals using Experimental Protocols Inspired by $K$-Theory Open
This repository contains Matlab scripts, COMSOL Multiphysics models, numerical simulation data used to generate the plots in the manuscript, and experimental measurements raw data. COMSOL models are those with the .mph extension and were c…
View article: Revealing Topology in Metals using Experimental Protocols Inspired by $K$-Theory
Revealing Topology in Metals using Experimental Protocols Inspired by $K$-Theory Open
This repository contains Matlab scripts, COMSOL Multiphysics models, numerical simulation data used to generate the plots in the manuscript, and experimental measurements raw data. COMSOL models are those with the .mph extension and were c…
View article: Revealing Topology in Metals using Experimental Protocols Inspired by $K$-Theory
Revealing Topology in Metals using Experimental Protocols Inspired by $K$-Theory Open
Topological metals are special conducting materials with gapless band structures and nontrivial edge-localized resonances, whose discovery has proved elusive because the traditional topological classification methods do not apply in this c…
View article: Topological D-Class Physics with Passive Acoustic Elements
Topological D-Class Physics with Passive Acoustic Elements Open
In this work, we supply an engineering solution that paves the way to the implementation of the full classification table of topological insulators with passive acoustic crystals. As an example, we design an acoustic crystal displaying the…
View article: Sources of quantized excitations via dichotomic topological cycles
Sources of quantized excitations via dichotomic topological cycles Open
We demonstrate the existence of a conceptually distinct topological pumping phenomenon in one-dimensional chains undergoing topological adiabatic cycles. Specifically, for a stack of two semi-infinite chains cycled in opposite directions a…