Researchers from the Complutense University of Madrid, IBM, ETH Zurich, MIT, and Harvard University have observed for the first time in a laboratory topological phases of matter associated with quantum states subjected to the action of temperature or presenting a certain type of imperfections. The experiment was carried out on an IBM superconducting cube platform, also called a quantum simulator.
The quantum simulators were conjectured for the first time by the Nobel prize of physics Richard Feynman in 1982, before the problem that underwent the classic computers that we handle at present to simulate systems of interacting quantum particles.
These simulators are genuinely quantum systems over which there is exquisite control (for example, cold atoms trapped with lasers, or superconducting materials coupled to microwave radiation) and which replicate other quantum systems that are more difficult to manipulate and of which they do not know some of their properties.
Quantum simulator with cubits
In an article published in the Quantum Information magazine of the Nature Publishing Group, these researchers explain how using a quantum simulator with IBM superconducting cubes, they were able to mimic materials called topological insulators at finite temperature and measure their phases for the first time associated quantum topologies.
The topological phases of matter are a very active research area that is revolutionizing our understanding of nature. The studies of these new phases of the matter have given rise to new materials such as topological insulators.
These materials behave as insulators inside and as a metal at the edges. The electronic currents of the edges have the spin (intrinsic magnetic moment) polarized and therefore it is expected to have a direct application in technologies such as spintronics, a novel alternative to conventional electronics.
Thermal Topological Phases
Since the discovery of topological matter, ways have been sought to maintain their properties by increasing the temperature. Previous theoretical work by researchers at the Complutense University proposed a new topological quantum phase, known as the Uhlmann phase, to characterize these phases of matter in a thermal system. The Uhlmann phase allows to generalize the topological phases of matter to systems with temperature.
The findings found in this experiment with quantum simulators represent the first measurement of topological quantum phases with temperature and it represents a great advance for the control and synthesis of topological matter with quantum technologies.
Among other applications, topological quantum matter has been proposed as “hardware” for future quantum computers due to its robustness against errors. The experimental results found in this work show how said quantum phases can also be resistant to thermal effects.