Why Physics is Fun, Stimulating, and Can Improve Lives
Majorana edge modes in topological superconductors
Two-dimensional superconductors with broken time-reversal symmetry have been predicted to support topologically protected chiral edge states, providing a superconducting counterpart to the quantum Hall effect in semiconductors. The edge states carry charge-neutral quasiparticles, coherent superpositions of electrons and holes referred to as 'Majorana fermions'. We present an overview of electrical and thermal probes of the superconducting edge states, focusing on unique signatures of their Majorana nature and on applications for topological quantum computation. In particular, we show how topological qubits can be braided by injecting them into the conducting edge of a superconductor.
Klaus von Klitzing
Max Planck Institute for Solid State Physics
The New International System of Units: A vision of Max Planck comes true
The discovery of the quantum Hall effect (QHE) revolutionized our international system of units (SI units). High precision measurements of the quantized Hall resistance opened up the way to relate fundamental constants directly to measured quantities. This triggered the introduction of a new international system of units based on constants of nature. The quantized Hall resistance is not only important for electrical standards but also for the realization of the mass unit kilogram.
Weizmann Institute of Science
Casimir effect meets the cosmological constant
In 1998 astronomers discovered that the expansion of the universe is accelerating. Somehow, something must have made gravity repulsive on cosmological scales. This something was called dark energy; it is described by Einstein’s cosmological constant; and it amounts to about 70% of the total mass of the universe. It has been conjectured that the cosmological constant is a form of vacuum energy, but its prediction from quantum field theory has failed by many orders of magnitude. The lecture shows how a theory informed by empirical evidence on Casimir forces does produce the correct order of magnitude and agrees with astronomical data, and how subtle this is.
Cristiane Morais Smith
Atom-by-atom engineering of novel states of matter
Feynman’s original idea of using one quantum system that can be manipulated at will to simulate the behavior of another more complex one has flourished during the last decades in the field of cold atoms. More recently, this concept started to be developed in nanophotonics and in condensed matter. In this talk, I will discuss a few recent experiments, in which 2D electron lattices were engineered on the nanoscale using STM manipulation of adatoms on the surface of copper. First, I will show that it is possible to control the geometry of the lattice and the orbital degrees of freedom by building different Lieb lattices. Then, I will show how to realize topological states of matter using the same procedure. We investigate the robustness of the zero modes in a breathing Kagome lattice, which is the first experimental realization of a designed electronic higher-order topological insulator, and the fate of the edge modes in a Kekule structure, upon varying the type of boundary of the sample. Finally, we will control the effective dimension of the electronic structure by creating a Sierpinski gasket, which has dimension D = 1.58. The realization of this first quantum fractal opens the path to electronics in fractional dimensions. In addition, our recent investigation of quantum transport in fractals by using photonic quantum simulators might shed some light on the issue of consciousness.
Treating cancer with nanotechnology