Testing Quantumness: From Artificial Quantum Arrays to Lattice Spin Models and Spin Liquids

Lead Research Organisation: University of Cambridge
Department Name: Physics

Abstract

Quantum mechanics is one of the best-confirmed theories in physics. Over the last two decades of steady and spectacular improvements in experimental techniques, there were no indications that quantum mechanics fails even when describing macroscopic systems.

We are now at the beginning of a "second quantum revolution'', where significant research efforts are being shifted from understanding quantum mechanical systems to applying essentially quantum properties of macroscopic systems in order to develop new quantum technologies (e.g., in quantum computing).

However, direct simulation of large enough systems with quantum mechanical behaviour is practically impossible, because of the astronomical computational resources it requires. Current developments in quantum engineering already brought us to face this barrier. It is therefore necessary to develop a set of approximate approaches, which are nonetheless precise enough, at least on average, to provide the understanding of and a guidance to the development of still larger artificial quantum systems, to the benefit of both fundamental science and cutting edge technology. In addition, magnetic materials, behaving quantum mechanically, require the same treatment with respect to their "quantumness", in this case in the thermodynamic limit. The goal of this project is to develop such a general theory and apply it to a number of important problems.

Publications

10 25 50
 
Description explored initial avenues of research and discussed relevant models. Established a collaborative structure with Loughborough. Explored some preliminary lattice spin systems. Investigated entanglement and negativity behavious at finite temperature in spin chains (in collaboration with project partner Prof Pollmann), and in 2D toy models (toric code). Development of mean field approaches for spin liquids; investigation of dynamics of quasiparticles in quantum spin liquids. Explored dimer models for high temperature superconductivity and found good agreement with experimental results. We proposed a mechanism for driven superconductivity.
We further developed an understanding of dephasing in spin chains and we are working on transferring it to higher dimensional systems.
We explored dynamics in pyrochlore oxides at the microscopic level and started exploring the collective behavour. We proposed a novel numerical approach to study quantum spin liquids, and in particular their excitations, at finite temperature. We characterised the dynamics and correlations in quantum spin liquids at finite temperature, where one type of excitation acts as disorder for the other, through their mutual anyonic statistics.
Exploitation Route scientific knowledge; experimental confirmation; potential technological interest in superconductivity
Sectors Education,Other

 
Description formation of outreach presentations; public lectures; graduate lectures at international schools
Sector Education,Other
 
Title Research data supporting "Color-dependent interactions in the three coloring model" 
Description Included in this archive is the software to generate the numerical values for the central charge, the data obtained from it for the cases studied and plotted in the paper, and the scripts to generate those plots from the data. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title Research data supporting "Color-dependent interactions in the three coloring model" 
Description Included in this archive is the software to generate the numerical values for the central charge, the data obtained from it for the cases studied and plotted in the paper, and the scripts to generate those plots from the data. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes