New Measurement Protocols Introduced for Categorizing Quantum States

April 16, 2020 by Luke James

A new protocol for defining quantum states can be directly applied in existing experimental platforms for quantum computing.

Topological materials have attracted a lot of interest and could provide the basis for a new era in materials development. Now, the physicists of Peter Zoller’s research group have presented a new measuring method, published in Science Advances.

The method allows for the identification and characterization of so-called topological invariants on several experimental platforms. 


Identifying and Measuring Topological Phases

These mathematical expressions describe the common properties of topological spaces. They make it possible to identify interacting topological states with global symmetry in one-dimensional, bosonic systems.

The new measurement protocols have been developed because topological phases cannot be identified by local measurements due to their special properties. 


A class of quantum states as topological states of matter.

A graphic depicting a class of quantum states as topological states of matter. Image used courtesy of IQOQI Innsbruck/Harald Ritsch


Impact on the EE Industry

In recent years, researchers have already achieved this for non-interacting systems. For interacting systems, however, the same cannot be said. Which could be one day used as topological quantum computers.

Zoller’s team hopes that their research will enable experimental physicists to characterize quantum state in the laboratory for these interacting systems.  


The Use of Quantum Mechanics

"The idea of our method is to first prepare such a topological state in a quantum simulator. Now so-called random measurements are performed, and topological invariants are extracted from statistical correlations of these random measurements," explains Andreas Elben, one of the authors on the paper.

This research could have a huge impact on the EE industry, with quantum mechanics being involved in one way or another in areas like spintronics, semiconductors, and optics.