EBQM · Ergodicity Breaking in Quantum Matter: From Many-Body Localisation to Quantum Glasses

Ergodicity Breaking in Quantum Matter: From Many-Body Localisation to Quantum Glasses

Left to their own devices, typical physical systems will eventually reach thermal equilibrium with their environment. While a familiar feature of life in the classical world – think of ice melting in a drink, or coffee cooling to room temperature – this process of thermalisation can pose a serious problem for quantum technologies. When a physical system thermalises, any information once contained in it is scrambled, essentially lost to the environment - the coffee does not ‘remember’ it was once hot, nor does the drink ‘remember’ it once contained an ice cube. The same principle holds true for quantum systems: if they undergo thermalisation, they will effectively have lost all information about how they were initially prepared. For future quantum technologies which will rely on the storage and retrieval of information (such as quantum computers), this loss of memory could be disastrous. One way to prevent a quantum system from thermalising is the addition of disorder. Disorder in quantum systems can come in many forms, from chemical impurities in solid-state materials through to the random speckle patterns of light used in ultracold atomic gas experiments, and has been the focus of a great deal of recent study as it holds great promise for the development of robust new quantum technologies. The main aim of this project was to explore novel ways that disorder could lead to novel mechanisms to inhibit thermalisation in near-future quantum technologies and be used to engineer stable quantum memories. Doing so required the development of an advanced new computational technique which led to the ability to simulate extremely large quantum systems up to extremely long timescales. The final results of the project support the existence of a long-lived quantum memory in one dimension in the presence of both random and pseudo-random 'disorder'. By contrast, in two dimensions it appears that the pseudo-random 'disorder' leads to significantly more stable quantum memory effects than purely random disorder. This has important implications for the future development of robust quantum memories for use in future quantum technologies.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз