Non-Ergodic Quantum Matter: Universality, Dynamics and Control

Projektinformationen

NEQuM

ID Finanzhilfevereinbarung: 850899

DOI

10.3030/850899

Projekt abgeschlossen

EK-Unterschriftsdatum 18 September 2019

Startdatum 1 Februar 2020

Enddatum 31 Januar 2025

Finanziert unter

• EXCELLENT SCIENCE - European Research Council (ERC)

Gesamtkosten

€ 1 498 420,00

EU-Beitrag

€ 1 498 420,00

Koordiniert durch

INSTITUTE OF SCIENCE AND TECHNOLOGY AUSTRIA
Austria

Periodic Reporting for period 4 - NEQuM (Non-Ergodic Quantum Matter: Universality, Dynamics and Control)

Berichtszeitraum: 2024-08-01 bis 2025-01-31

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

The main goal of this project is to develop theory of non-equilibrium quantum systems that avoid thermal equilibrium. This theory aims to scope such properties of these systems as their eigenstates, dynamics and ways to control them. This problem touches the fundamental question of how/when statistical mechanics fails to emerge in isolated quantum systems that consist of many interacting particles. On the one hand, the expectation is that from understanding examples of breakdown of thermalization we also learn new insights into thermalization – a fundamental insights into laws of nature. On the other hand, the non-ergodic quantum system may have potential uses in storing and manipulating quantum information thus being helpful in the ongoing effort towards scalable quantum computations. The theory of the non-ergodic systems developed in this grant may help in both directions.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

During the duration of the project we studied dynamics and eigenstates of non-ergodic systems such as many-body localized systems and quantum many-body scars, also devised novel ways for quantum control. Main result include:
1. existence of mobility edges in the many-body localized systems.
2. study of many-body localized eigenstates and dynamics, and pushing the matrix product states time evolution methods beyond the state of the art
3. theoretical description of quantum many-body scars and experimental collaboration with Lukin’s group (Harvard univ.) confirmed the existence of quantum many-body scars in two dimensional systems of Rydberg atoms.
4. using results for scars, we constructed theory explaining experiments and devised ways of controlling dynamics of quantum scars via the periodic driving – an important milestone in the third direction of controlling non-ergodic systems
5. we created new method for control of many-body quantum systems along a given trajectory in the state space
These results, and many others, were disseminated at a more than 30 conferences and workshops, as well as in press releases and social media.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

The results obtained during this project are beyond the state of the art. In particular, we obtained
1. numerical simulations of the dynamics of many-body localized systems used parallel algorithm and achieved very large bond dimensions needed to capture the large entanglement present in the system
2. new analytical and numerical techniques to address the properties of quantum many-body scars, based on tensor networks and algebraic methods
3. new tensor networks based approaches for quantum control and obtaining Floquet eigenstates with tensor networks
Therefore the project advanced methods for accessing eigenstates, dynamics, and controlling non-ergodic systems.

Improving quantum scars by periodic driving