First confirmation of new theory by metamaterial

Date:
June 10, 2020
Source:
University of Wu"rzburg
Summary:
Physicists have experimentally demonstrated a novel effect for
the first time by exploiting topological metamaterials.



FULL STORY ========================================================================== Topological metamaterials are applied as a novel platform to explore
and study extraordinary effects. Instead of using natural materials, researchers artificially arrange the constituents of a topological
metamaterial in a regular structure. Such an arrangement is analogous
to a solid state in which the atoms form a crystal lattice. Usually,
these platforms are used to simulate particular properties of solids in
order to make them amenable to experimental investigation.


========================================================================== Physicists at Julius-Maximilians-Universita"t (JMU) Wu"rzburg in Bavaria, Germany, perform research on those topological metamaterials, a central
scheme of the Wu"rzburg-Dresden Cluster of Excellence ct.qmat --
Complexity and Topology in Quantum Matter.

Novel topological phenomena A related motif of solid state research in Wu"rzburg is the discovery and characterization of novel topological
phenomena. This concerns the study of topological insulators, which are insulating in the bulk, but feature conducting surface states. Scientists worldwide engage in intensive research on these materials as they exhibit compelling physical phenomena. One day, this research may lead to advances
in semiconductor technology or in other fields.

The JMU researchers report on their newest results in the journal Nature Physics. Topological insulators are usually considered as isolated
(Hermitian) systems. In contrast, scientists can tweak topological metamaterials such as to study the implications of energy exchange
with the environment. These interactions influence the behaviour of the
system from the outside, as would be the case for friction. This way,
they experimentally verified the non- Hermitian skin effect (NHSE)
previously predicted in theory.

All states localize at the edge The NHSE involves that, in contrast to a
common topological insulator, not only a small fraction but all states
of the material appear at its edge, i.e. are localized there. This is
described by Tobias Helbig and Tobias Hofmann, the joint first authors
of the publication. They are both PhD students in the research group of Professor Ronny Thomale, head of the JMU Chair of Theoretical Physics I.



==========================================================================
"Our research shows, among other things, that the physical principles
known from isolated solid state systems need to be fundamentally modified
in the non- Hermitian case," the PhD students explain. The new findings
would not yet have a direct application. However, they do have the
potential to improve highly sensitive optical detectors, as an example.

Electric circuits as a center of innovation in basic research The
experiments leading to the new results were conducted with the group
of Dr.

Tobias Kiessling and the JMU Chair of Experimental Physics III. Additional contributions and ideas have been brought forward by Professor Alexander Szameit from the University of Rostock. JMU Physicists cooperate with
Szameit's team on the topic of topological photonics within the cluster
of excellence ct.qmat.

In order to demonstrate the non-Hermitian skin effect experimentally,
the JMU team has used electric circuits with periodically arranged
elements. Due to their resemblance to the crystal structure of a solid,
such artificially arranged experimental settings are classified as
a metamaterial.

Applications of topological matter in sight Prospectively, the research
team wants to investigate the interplay between topological states and non-Hermitian physics further. One key question will be to which extent
the topological protection of states remains intact when interactions
with the environment are present.

In the long term, the team intends to progress towards quantum hybrid
circuits in which they plan to embed superconducting or other quantum mechanical circuit elements. Such circuits offer a versatile platform
for the discovery of novel phenomena.

"We aim to transfer the insights from topological circuits to other metamaterial platforms in the pursuit of potential applications,"
Professor Thomale sums up. This includes optical setups such as photonic waveguides.

There, topologically protected states in non-Hermitian systems could
prove relevant in the enhancement of signal processing and detectors as
well as in the construction of a photonic quantum computer. Eventually,
the ultimate scheme in the research on topological metamaterials is the reconnection of novel effects to actual solid states.


========================================================================== Story Source: Materials provided by University_of_Wu"rzburg. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. T. Helbig, T. Hofmann, S. Imhof, M. Abdelghany, T. Kiessling, L. W.

Molenkamp, C. H. Lee, A. Szameit, M. Greiter,
R. Thomale. Generalized bulk-boundary correspondence in
non-Hermitian topolectrical circuits.

Nature Physics, 2020; DOI: 10.1038/s41567-020-0922-9 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200610112045.htm

--- up 20 weeks, 1 day, 2 hours, 34 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)