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Concept

Quantum critical point

Publications associées (32)

Universal Aspects of Metamagnetic Transitions in Frustrated Ising Chains

Nagabhushan Ganesh Hegde

The study of magnetic frustration has been interesting due to the variety of magnetic ordering observed at low temperatures. At these temperatures thermal fluctuations become redundant and quantum fluctuations play a significant role in the determining the ...

EPFL2021

Dynamical properties of a driven dissipative dimerized S=1/2 chain

Bruce Normand

We consider the dynamical properties of a gapped quantum spin system coupled to the electric field of a laser, which drives the resonant excitation of specific phonon modes that modulate the magnetic interactions. We deduce the quantum master equations gov ...

2021

Critical values in an anisotropic percolation on $\mathbb{Z}^2$

Hao Xue

In this thesis, we consider an anisotropic finite-range bond percolation model on

\mathbb{Z}^2

. On each horizontal layer

\{(x,i):x\in\mathbb{Z}\}

for

i\in\mathbb{Z}

, we have edges

\langle(x,i),(y,i)\rangle

for

1\leq|x-y|\leq N

with $N\in\mathbb{N ...

EPFL2021

Tunneling processes through magnetic impurities on superconducting surfaces: Yu-Shiba-Rusinov states and the Josephson effect

Haonan Huang

Magnetic impurities generate a wealth of phenomena on surfaces. On metals, conducting electrons screen the magnetic moment giving rise to the Kondo effect. On superconductors, the Yu-Shiba-Rusinov (YSR) states emerge inside the superconducting gap due to t ...

EPFL2021

Classical Spin Liquid or Extended Critical Range in h-YMnO3?

Jakob Lass, Sofie Janas

Neutron spectroscopy on the classical triangular-lattice frustrated antiferromagnet h-YMnO3 reveals diffuse, gapless magnetic excitations present both far below and above the ordering temperature. The correlation length of the excitations increases as the ...

AMER PHYSICAL SOC2021

Order and dynamics in Kagome like compound Cu2OSO4 and other quantum magnets

Virgile Yves Favre

This thesis presents results of studies of novel compounds modeling complex fundamental physics phenomena. Cu2OSO4 is a copper based magnetic Mott Insulator system, where spin half magnetic moments form a new type of lattice. These intrinsically quantum pi ...

EPFL2021

Antiferromagnetic fluctuations and charge carrier localization in ferromagnetic bilayer manganites: electrical resistivity scales exponentially with short-range order controlled by temperature and magnetic field

Gabriel Aeppli

The compound La2-2xSr1+2xMn2O7,x= 0.30-0.40, consists of bilayers of ferromagnetic metallic MnO(2)sheets that are separated by insulating layers. The materials show colossal magnetoresistance-a reduction in resistivity of up to two orders of magnitude in a ...

2020

Quantum phase transitions and the role of impurity-substrate hybridization in Yu-Shiba-Rusinov states

Klaus Kern, Jacob Senkpiel, Haonan Huang

Spin-dependent scattering from magnetic impurities inside a superconductor gives rise to Yu-Shiba-Rusinov (YSR) states within the superconducting gap. They can be modeled by the largely equivalent Kondo or Anderson impurity models. The role of the magnetic ...

NATURE RESEARCH2020

Spin-1/2 kagome Heisenberg antiferromagnet with strong breathing anisotropy

Frédéric Mila

We study the zero-temperature phase diagram of the spin-1/2 Heisenberg model with breathing anisotropy (i.e., with different coupling strength on the upward and downward triangles) on the kagome lattice. Our study relies on large scale tensor network simul ...

SCIPOST FOUNDATION2020

First-order Neel to columnar valence bond solid transition in a model square-lattice S=1 antiferromagnet

Jonathan D'Emidio

We study the Neel to fourfold columnar valence bond solid (cVBS) quantum phase transition in a sign-free S = 1 square-lattice model. This is the same kind of transition that for S = 1/2 has been argued to realize the prototypical deconfined critical point. ...

AMER PHYSICAL SOC2020

Journal of Physics: Conference Series High-pressure specific heat technique to uncover novel states of quantum matter

Henrik Moodysson Rønnow, Julio Antonio Larrea Jiménez

AC-specific heat measurements remain as the foremost thermodynamic experimental method to underpin phase transitions in tiny samples. However, its performance under combined extreme conditions of high-pressure, very low temperature and intense magnetic fie ...

IOP PUBLISHING LTD2020

Quantum spin-liquid states in an organic magnetic layer and molecular rotor hybrid

László Forró, Bálint Náfrádi, Edoardo Martino, Andrea Pisoni, Péter Szirmai, Konstantins Mantulnikovs

The exotic properties of quantum spin liquids (QSLs) have continually been of interest since Anderson's 1973 ground-breaking idea. Geometrical frustration, quantum fluctuations, and low dimensionality are the most often evoked material's characteristics th ...

National Academy of Sciences2020