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Concept

Dirac spinor

Publications associées (28)

Hausdorff dimension of fermions on a random lattice

Mattia Guerino Varrone

Geometric properties of lattice quantum gravity in two dimensions are studied numerically via Monte Carlo on Euclidean Dynamical Triangulations. A new computational method is proposed to simulate gravity coupled with fermions, which allows the study of int ...

Elsevier2024

Spin wave spectra of single crystal CoPS3

Henrik Moodysson Rønnow, Luc Testa

The spin waves in single crystals of the layered van der Waals antiferromagnet CoPS3 have been measured using inelastic neutron scattering. The data show four distinct spin wave branches with large (>14 meV) energy gaps at the Brillouin zone center indicat ...

2023

Diffuse spin waves and classical spin liquid behavior in the kagome antiferromagnet chromium jarosite, KCr3(OD)6(SO4)2

Ivica Zivkovic, Sofie Janas

The dynamics of the S = 3/2 kagome antiferromagnet chromium jarosite, KCr3(OD)(6)(SO4)(2), was studied using high-resolution neutron time-of-flight spectroscopy on a polycrystalline sample with a nearly stoichiometric magnetic lattice [2.8(2)% Cr vacancies ...

Amer Physical Soc2023

Hierarchy of quasisymmetries and degeneracies in the CoSi family of chiral crystal materials

Philip Johannes Walter Moll, Yi-Chiang Sun, Chunyu Guo

In materials, certain approximated symmetry operations can exist in a lower-order approximation of the effective model but are good enough to influence the physical responses of the system, and these approximated symmetries were recently dubbed "quasisymme ...

AMER PHYSICAL SOC2023

Possibility to detect the bound state of the Heisenberg ferromagnetic chain at intermediate temperature

Frédéric Mila, Mithilesh Nayak

Motivated by the lack of direct evidence with inelastic neutron scattering of the well documented bound state of Heisenberg ferromagnets, we use the time-dependent thermal density matrix renormalization group algorithm to study the temperature dependence o ...

2022

Static and dynamic properties of non-collinear quantum antiferromagnets explored by neutron scattering

Luc Testa

This thesis is devoted to the investigation of static and dynamic properties of two different sets of quantum magnets with neutron scattering techniques and the help of linear spin wave theory. Both systems are copper-based with spin-1/2, which makes them ...

EPFL2021

Confined dipole and exchange spin waves in a bulk chiral magnet with Dzyaloshinskii-Moriya interaction

Helmuth Berger, Dirk Grundler, Andrea Mucchietto, Ping Che

The Dzyaloshinskii-Moriya interaction (DMI) has an impact on excited spin waves in the chiral magnet Cu2OSeO3 by means of introducing asymmetry in their dispersion relations. The confined eigenmodes of a chiral magnet are hence no longer the conventional s ...

2021

Momentum space CFT correlators for Hamiltonian truncation

Matthew Thomas Walters

We consider Lorentzian CFT Wightman functions in momentum space. In particular, we derive a set of reference formulas for computing two- and three-point functions, restricting our attention to three-point functions where the middle operator (corresponding ...

Springer Nature2020

Conformal 3-Point Functions and the Lorentzian OPE in Momentum Space

Marc Gillioz

In conformal field theory in Minkowski momentum space, the 3-point correlation functions of local operators are completely fixed by symmetry. Using Ward identities together with the existence of a Lorentzian operator product expansion (OPE), we show that t ...

SPRINGER2020

Non-Abelian reciprocal braiding of Weyl points and its manifestation in ZrTe

Oleg Yazyev, Quansheng Wu

Weyl points in three-dimensional systems with certain symmetry carry non-Abelian topological charges, which can be transformed via non-trivial phase factors that arise upon braiding these points inside the reciprocal space. ...

NATURE PUBLISHING GROUP2020

Probing intraband excitations in ZrTe5: A high-pressure infrared and transport study

Helmuth Berger, Ana Akrap, Philip Johannes Walter Moll, Matthias Carsten Putzke, Edoardo Martino, Mathieu François Padlewski

Zirconium pentatetelluride, ZrTe5, shows remarkable sensitivity to hydrostatic pressure. In this work we address the high-pressure transport and optical properties of this compound, on samples grown by flux and chemical vapor transport. The high-pressure r ...

2020

Two-dimensional Rashba metals: Unconventional low-temperature transport properties

Claudio Grimaldi

Rashba spin-orbit coupling emerges in materials lacking of structural inversion symmetry, such as heterostructures, quantum wells, surface alloys and polar materials, just to mention few examples. It yields a coupling between the spin and momentum of elect ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Fermion conformal bootstrap in 4d

Alessandro Vichi, Denis Karateev

We apply numerical conformal bootstrap techniques to the four-point function of a Weyl spinor in 4d non-supersymmetric CFTs. We find universal bounds on operator dimensions and OPE coefficients, including bounds on operators in mixed symmetry representatio ...

Springer Nature2019

Novel families of SU(N) AKLT states with arbitrary self-conjugate edge states

Frédéric Mila, Samuel Gozel

Using the Matrix Product State framework, we generalize the Affleck-Kennedy-Lieb-Tasaki (AKLT) construction to one-dimensional spin liquids with global color SU(N) symmetry, finite correlation lengths, and edge states that can belong to any self-conjugate ...

2019

Efficient Multi-dimensional Diracs Estimation with Linear Sample Complexity

Martin Vetterli, Thierry Blu, Hanjie Pan

Estimating Diracs in continuous two or higher dimensions is a fundamental problem in imaging. Previous approaches extended one dimensional methods, like the ones based on finite rate of innovation (FRI) sampling, in a separable manner, e.g., along the hori ...

2018

Spin dynamics of coupled spin ladders near quantum criticality in Ba2CuTeO6

Frédéric Mila

We report inelastic neutron scattering measurements of the magnetic excitations in Ba2CuTeO6, proposed by ab initio calculations to magnetically realize weakly coupled antiferromagnetic two-leg spin-1/2 ladders. Isolated ladders are expected to have a sing ...

2018

Magnetic excitations from the two-dimensional interpenetrating Cu framework in Ba2Cu3O4Cl2

Henrik Moodysson Rønnow, Peter Babkevich, Diane Virginie Marie Lançon, Noore Elahi Shaik

We report detailed neutron scattering studies on Ba2Cu3O4Cl2. The compound consists of two interpenetrating sublattices of Cu, labeled as Cu-A and Cu-B, each of which forms a square-lattice Heisenberg antiferromagnet. The two sublattices order at different ...

Amer Physical Soc2017

Magnetic Excitations and Electronic Interactions in Sr2CuTeO6: A Spin-1/2 Square Lattice Heisenberg Antiferromagnet

Henrik Moodysson Rønnow, Oleg Yazyev, Peter Babkevich, Vamshi Mohan Katukuri

Sr2CuTeO6 presents an opportunity for exploring low-dimensional magnetism on a square lattice of S = 1/2 Cu2+ ions. We employ ab initio multireference configuration interaction calculations to unravel the Cu2+ electronic structure and to evaluate exchange ...

2016

The classical and quantum dynamics of molecular spins on graphene

Klaus Kern, Marko Burghard, Stephan Rauschenbach

Controlling the dynamics of spins on surfaces is pivotal to the design of spintronic(1) and quantum computing(2) devices. Proposed schemes involve the interaction of spins with graphene to enable surface-state spintronics(3,4) and electrical spin manipulat ...

Nature Publishing Group2016

Unconventional transformation of spin Dirac phase across a topological quantum phase transition

Jan Hugo Dil

The topology of a topological material can be encoded in its surface states. These surface states can only be removed by a bulk topological quantum phase transition into a trivial phase. Here we use photoemission spectroscopy to image the formation of prot ...

Nature Publishing Group2015