Lecture

Fragmentation in Spin Ice Systems

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Description

This lecture explores the concept of fragmentation in spin ice systems, focusing on the magnetic ice rules, spin ice models, monopole vacuum, emergent gauge fields, topological defects, and monopole crystal phases. The instructor discusses the emergence of hard core dimers, the Dirac string protocol, and the KII phase of kagomé ice, highlighting the experimental results and neutron scattering signatures. The lecture concludes with a discussion on quantum Monte Carlo simulations of quantum spin ice, emphasizing the ordering out of the dimer liquid phase and the neutron scattering signatures for different phases.

Official source

Related concepts (32)

Topological order

In physics, topological order is a kind of order in the zero-temperature phase of matter (also known as quantum matter). Macroscopically, topological order is defined and described by robust ground state degeneracy and quantized non-Abelian geometric phases of degenerate ground states. Microscopically, topological orders correspond to patterns of long-range quantum entanglement. States with different topological orders (or different patterns of long range entanglements) cannot change into each other without a phase transition.

Topological defect

Topological defects or solitons are irregularities or disruptions that occur within continuous fields or ordered states of matter. These defects, which can take various forms such as points, lines, or surfaces, are characterized by their stability and the fact that they cannot be 'smoothed out' or removed through continuous transformations of the field or material. They play a significant role in various areas of physics, including condensed matter physics, cosmology, and quantum field theory, and can have profound effects on the properties and behavior of the systems in which they occur.

Topological insulator

A topological insulator is a material whose interior behaves as an electrical insulator while its surface behaves as an electrical conductor, meaning that electrons can only move along the surface of the material. A topological insulator is an insulator for the same reason a "trivial" (ordinary) insulator is: there exists an energy gap between the valence and conduction bands of the material. But in a topological insulator, these bands are, in an informal sense, "twisted", relative to a trivial insulator.

Topological quantum computer

A topological quantum computer is a theoretical quantum computer proposed by Russian-American physicist Alexei Kitaev in 1997. It employs quasiparticles in two-dimensional systems, called anyons, whose world lines pass around one another to form braids in a three-dimensional spacetime (i.e., one temporal plus two spatial dimensions). These braids form the logic gates that make up the computer. The advantage of a quantum computer based on quantum braids over using trapped quantum particles is that the former is much more stable.

Topological quantum number

In physics, a topological quantum number (also called topological charge) is any quantity, in a physical theory, that takes on only one of a discrete set of values, due to topological considerations. Most commonly, topological quantum numbers are topological invariants associated with topological defects or soliton-type solutions of some set of differential equations modeling a physical system, as the solitons themselves owe their stability to topological considerations.

Related lectures (49)

Designer Quantum Materials: Van der Waals Heterostructures

Explores designer quantum materials in van der Waals heterostructures, focusing on topological superconductivity and moiré-modulated Shiba bands.

Symmetry Breaking: Magnetic Fields in Cosmology

Covers symmetry breaking and its role in generating magnetic fields in cosmology.

Topological matter and its exploration

Explores topological matter using quantum gases, covering the SSH and Rice-Mele models, adiabatic pump, and Berry curvature measurement.

Topological Matter with Ultracold Dysprosium Atoms

Explores synthetic topological matter with ultracold dysprosium atoms, covering topology, the Hall effect, quantum simulation, and entanglement spectrum.

Magnetic Moments and Spin