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Concept

Topological string theory

Related publications (32)

On Topological Equivalence in Linear Quadratic Optimal Control

Daniel Kuhn, Wouter Jongeneel

Dynamical systems are topologically equivalent when their orbits can be mapped onto each other via a homeomorphic change of coordinates. We will show that in general, closed-loop systems resulting from Linear Quadratic Optimal Control problems are all topo ...

2021

Observation of a singular Weyl point surrounded by charged nodal walls in PtGa

Oleg Yazyev, Jan Hugo Dil, Quansheng Wu, Shengnan Zhang

Constrained by the Nielsen-Ninomiya no-go theorem, in all so-far experimentally determined Weyl semimetals (WSMs) the Weyl points (WPs) always appear in pairs in the momentum space with no exception. As a consequence, Fermi arcs occur on surfaces which con ...

Nature Research2021

Unified analysis of topological defects in 2D systems of active and passive disks

Ignacio Pagonabarraga Mora, Pasquale Digregorio

We provide a comprehensive quantitative analysis of localized and extended topological defects in the steady state of 2D passive and active repulsive Brownian disk systems. We show that, both in and out-of-equilibrium, the passage from the solid to the hex ...

ROYAL SOC CHEMISTRY2021

Motile dislocations knead odd crystals into whorls

Sofia Magkiriadou

The competition between thermal fluctuations and potential forces governs the stability of matter in equilibrium, in particular the proliferation and annihilation of topological defects. However, driving matter out of equilibrium allows for a new class of ...

NATURE PORTFOLIO2022

Global bifurcation at isolated singular points of the Hadamard derivative

Charles Stuart

Consider F is an element of C(RxX,Y) such that F(lambda, 0) = 0 for all lambda is an element of R, where X and Y are Banach spaces. Bifurcation from the line Rx{0} of trivial solutions is investigated in cases where F(lambda, center dot ) need not be Frech ...

2021

Dipolar-stabilized first and second-order antiskyrmions in ferrimagnetic multilayers

Dirk Grundler, Ping Che

Skyrmions and antiskyrmions are topologically protected spin structures with opposite vorticities. Particularly in coexisting phases, these two types of magnetic quasi-particles may show fascinating physics and potential for spintronic devices. While skyrm ...

Nature Research2021

Remote Doping of Scalable Nanowire Branches

Anna Fontcuberta i Morral, Wonjong Kim, Martin George Friedl, Lucas Güniat, Didem Dede, Nicholas Paul Morgan

Selective-area epitaxy provides a path toward high crystal quality, scalable, complex nanowire networks. These high-quality networks could be used in topological quantum computing as well as in ultrafast photodetection schemes. Control of the carrier densi ...

2020

Large magnetoresistance and nonzero Berry phase in the nodal-line semimetal MoO2

Oleg Yazyev, Quansheng Wu, Shengnan Zhang

We performed calculations of the electronic band structure and the Fermi surface as well as measured the longitudinal resistivity rho(xx)(T,H), Hall resistivity rho(xy)(T,H), and quantum oscillations of the magnetization as a function of temperature at var ...

2020

Magnon Modes of Microstates and Microwave-Induced Avalanche in Kagome Artificial Spin Ice with Topological Defects

Dirk Grundler, Vinayak Shantaram Bhat

We investigate spin dynamics of microstates in artificial spin ice (ASI) in Ni81Fe19 nanomagnets arranged in an interconnected kagome lattice using microfocus Brillouin light scattering, broadband ferromagnetic resonance, magnetic force microscopy, x-ray p ...

2020

Charge transport in proximitized graphene within van der Waals heterostructures

Katharina Polyudov

Since their discovery, graphene and other 2D materials have become a subject of intense research in condensed matter physics. Especially the vast possibilities of combining those materials into heterostructures are promising for the discovery of novel phys ...

EPFL2020

Scalable Nanowire Networks: Growth and Functionality

Martin George Friedl

With the rise of quantum computing and recent experiments into topological quantum computers come exciting new opportunities for III-V semiconductor quantum nanostructures. In this thesis, we explore the scalable fabrication of patterned arrays and branche ...

EPFL2020

Influence of Minor Cr Additions on Crystal Growth in Rapidly Solidified Al-20Zn Alloys

Michel Rappaz

It has been discovered quite recently that Icosahedral Short-Range Order (ISRO) of atoms in the liquid phase of metallic alloys surrounding some trace elements added to the melt can influence both the nucleation and growth of the primary phase. In this wor ...

2020