Description du projet
Se pencher sur les propriétés de la matière quantique non ergodique
Les systèmes ergodiques occupent une place centrale dans la mécanique statistique puisqu’ils atteignent l’équilibre thermique, ce qui permet de faire des descriptions classiques générales. À l’inverse, les systèmes quantiques non ergodiques à plusieurs corps ne parviennent pas à la thermalisation et peuvent, par conséquent, avoir la possibilité de conserver leur nature quantique pendant de longues périodes. Le projet NEQuM, financé par l’UE, vise à mieux comprendre la dynamique et les propriétés de ces systèmes quantiques isolés, en explorant différentes voies de rupture de l’ergodicité, notamment le désordre, la frustration et les symétries cachées. Les résultats du projet, issus de nouvelles techniques analytiques et numériques, jetteront les bases d’une théorie générale des systèmes quantiques hors équilibre. La capacité des systèmes non ergodiques à rester quantiques sur des échelles de temps plus longues a de nombreuses applications pratiques, non seulement pour la science mais aussi pour les technologies émergentes. Les systèmes quantiques désordonnés en offrent un bon exemple et pourraient être extrêmement utiles pour les futures technologies de stockage et de traitement de l’information.
Objectif
In this project we propose to build the theory of non-ergodic quantum matter – isolated quantum systems that avoid thermal equilibrium. To this end, we will study the established non-ergodic phases, search for new phases, and seek to understand their common properties and dynamics. Recently non-ergodic systems that avoid the fate of thermal equilibrium were realized experimentally in quantum simulators. Specific examples include many-body localized phases, glassy and kinetically constrained models, and systems with weak ergodicity breaking. Freedom from the laws of equilibrium statistical mechanics opens up a host of possible unexpected behaviors prohibited in equilibrium. The ability of non-ergodic systems to stay quantum on longer timescales has potential for practical applications. This calls for the development of a general theory of non-ergodic quantum systems. In order to develop such theory, in this project we will seek to address the questions: What are the possible ways to avoid attaining thermal equilibrium? What are the universal properties of such non-ergodic systems? What is the nature of their long time dynamics and their steady state? How can we put their properties to use? The PI will leverage his expertise in studies of many-body localization to lead a coherent research program aimed at (i) describing universal properties of highly-excited eigenstates and their entanglement; (ii) developing new methods to simulate non-ergodic dynamics and reveal its experimental signatures; and (iii) using such quantum phases for many-body state preparation and optimal control. The theory delivered by this project will ultimately provide useful insights into quantum thermalization, thus establishing the first steps towards a general theory of non-equilibrium quantum systems. On the practical side, such theory will guide the experimental search for non-ergodic phases, and open the door to their application in more efficient quantum information storage and processing.
Champ scientifique
Programme(s)
Thème(s)
Régime de financement
ERC-STG - Starting GrantInstitution d’accueil
3400 Klosterneuburg
Autriche