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Concept

Paul Dirac

Publications associées (28)

Magnon-phonon interactions enhance the gap at the Dirac point in the spin-wave spectra of CrI3 two-dimensional magnets

Iurii Timrov

Recent neutron-diffraction experiments in honeycomb CrI3 quasi-2D ferromagnets have evinced the existence of a gap at the Dirac point in their spin-wave spectra. The existence of this gap has been attributed to strong in-plane Dzyaloshinskii-Moriya or Kita ...

2023

Wigner Gaussian dynamics: Simulating the anharmonic and quantum ionic motion

Lorenzo Monacelli

The atomic motion controls important properties of materials, such as thermal transport, phase transitions, and vibrational spectra. However, simulating the ionic dynamics is exceptionally challenging when quantum fluctuations are relevant (e.g., at low te ...

AMER PHYSICAL SOC2023

Thermal Evolution of Dirac Magnons in the Honeycomb Ferromagnet CrBr3

Bruce Normand, Christian Rüegg, Andreas Martin Läuchli Herzig

CrBr3 is an excellent realization of the two-dimensional honeycomb ferromagnet, which offers a bosonic equivalent of graphene with Dirac magnons and topological character. We perform inelastic neutron scattering measurements using state-of-the-art instrume ...

2022

Collective behavior and emerging patterns in dense dry aligning active matter

Elena Sesé Sansa

In this thesis, we study systems of active particles interacting via generic torques of different nature. We analyze the phase behavior of these systems, which results from the interplay between self-propulsion, excluded-volume and torques. We tackle the p ...

EPFL2022

Experimental Observation and Spin Texture of Dirac Node Arcs in Tetradymite Topological Metals

Emmanouil Frantzeskakis, Ji Dai

We report the observation of a nontrivial spin texture in Dirac node arcs, i.e., novel topological objects formed when Dirac cones of massless particles extend along an open one-dimensional line in momentum space. We find that such states are present in al ...

AMER PHYSICAL SOC2021

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2As2

Joël Mesot, Thomas Pierre Richard Zilliox

Parity-time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realizatio ...

Wiley-V C H Verlag Gmbh2020

NMR Study of Spin Dynamics in V7Zn and V7Ni Molecular Rings

Alice Radaelli

We present a(1)H NMR investigation of spin dynamics in two finite integer spin molecular nanomagnetic rings, namely V7Zn and V7Ni. This study could be put in correlation with the problem of Haldane gap in infinite integer spin chains. While V7Zn is an appr ...

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

Ultrathin Junctionless Nanowire FET Model, Including 2-D Quantum Confinements

Farzan Jazaeri

In this paper, we develop an explicit model to predict the dc electrical behavior in ultrathin surrounding gate junctionless (JL) nanowire field-effect transistors (FETs). The proposed model considers 2-D electrical and geometrical confinements of carrier ...

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

Unconventional photon blockade

Vincenzo Savona, Hugo Pierre Alexandre Flayac

We review the unconventional photon blockade mechanism. This quantum effect remarkably enables a strongly sub-Poissonian light statistics, even from a system characterized by a weak single-photon nonlinearity. We revisit the past results, which can be inte ...

Amer Physical Soc2017

Evolution of the Fermi surface of BiTeCl with pressure

Helmuth Berger

We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeCl under applied pressures up to similar to 2.5 GPa. We observe two distinct oscillation frequencies, corresponding to the Rashba-split inner and outer Fermi sur ...

Iop Publishing Ltd2017

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

Manifestation of a Second Dirac Surface State and Bulk Bands in THz Radiation from Topological Insulators

Helmuth Berger

Topological insulators (TIs) are interesting quantum matters that have a narrow bandgap for bulk and a Dirac-cone-like conducting surface state (SS). The recent discovered second Dirac surface state (SS) and bulk bands (BBs) located similar to 1.5 eV above ...

Nature Publishing Group2015

Germanene: the germanium analogue of graphene

Lei Zhang, Magalí Alejandra Lingenfelder

Recently, several research groups have reported the growth of germanene, a new member of the graphene family. Germanene is in many aspects very similar to graphene, but in contrast to the planar graphene lattice, the germanene honeycomb lattice is buckled ...

Institute of Physics2015

Electronic Structure of Graphene and Topological Insulators : Frequency and Time-domain Perspectives

Jens Christian Johannsen

The study of the electronic band structure of solids is a central task in materials science. Indeed, knowing a material's band structure is key to an understanding of its macroscopic electronic properties. In recent years, a new class of materials has emer ...

EPFL2015

Moments And Growth Indices For The Nonlinear Stochastic Heat Equation With Rough Initial Conditions

Robert Dalang, Le Chen

We study the nonlinear stochastic heat equation in the spatial domain R, driven by space-time white noise. A central special case is the parabolic Anderson model. The initial condition is taken to be a measure on R, such as the Dirac delta function, but th ...

Inst Mathematical Statistics2015

Strings from domain walls in supersymmetric Yang-Mills theory and adjoint QCD

We study strings between static quarks in QCD with nf adjoint fermions, including N = 1 supersymmetric Yang-Mills (SYM), in the calculable regime on R-3 x S-L(1), which shares many features with the XY-spin model. We find that they have many qualitatively ...

American Physical Society2015

Pressure tuning the Fermi level through the Dirac point of giant Rashba semiconductor BiTeI

Helmuth Berger

We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeI under applied pressures up to similar to 2GPa. We observe one high frequency oscillation at all pressures and one low frequency oscillation that emerges betwee ...

Iop Publishing Ltd2014

Dirac Structures, Nonholonomic Systems And Reduction

Tudor Ratiu, Madeleine Jotz

The reduction of nonholonomic systems is formulated in terms of Dirac reduction. An optimal reduction method for a class of nonholonomic systems is formulated. Several examples are studied in detail. ...

Elsevier2012