2023-24-project-catalogue

###Many-body entanglement dynamics in open and closed quantum systems.

Project ID: 2228bd1098 (You will need this ID for your application)

Research Theme: Physical Sciences

UCL Lead department: London Centre for Nanotechnology (LCN)

Department Website

Lead Supervisor: Andrew Green

Project Summary:

By focussing upon the entanglement structure of many-body quantum states, tensor networks have yielded tremendous insights about the nature of many-body quantum dynamics [1]. This project will involve using tensor network methods to reveal novel quantum dynamics – such as slowed entanglement growth in fractionalised and scarred many-body quantum systems [2], quantum chaos and thermalisation [3] – and developing new methods and algorithms to encode insights so obtained [4,5]. The project will contribute fundamental understanding of quantum mechanics, yield new algorithms for the classical simulation of quantum systems, and potentially new algorithms to run such simulations on quantum computers. The focus will be upon fundamental understanding of two related questions: i. analytical understanding of the many-body Zeno transition by which coupling to the environment restricts the growth of quantum entanglement in open quantum systems [6,7,8]; ii. develop new algorithms that embody how restricting observations of quantum system to a small window can be used in some circumstances to obtain a self-consistent description of the system dynamics for all time [7,8]. The ideal candidate for this project will be a physics, theoretical physics or mathematics graduate with strong mathematical and numerical skills and broad interest in the fundamental principles of quantum mechanics and quantum field theory.

[1] Orús Annals of physics 349, 117–158 (2014) [2] Turner et al Nature Physics 14, 745 (2018) [3] Hallam et al Nature comms. 10, 1–8 (2019) [4] Lin et al PRX Quantum 2, 010342 (2021) [5] Barratt et al npj QI 7, 1 (2021) [6] Azad et al ArXiv:2111.06408 (2022) [7] Nahum et al Physical Review X7, 031016 (2017) [8] von Keyserlingk et al Phys Rev X8, 021013 (2018) [9] White et al Physical Review B 97, 035127 (2018) [10] Rakovszky et al. Phys Rev B 105, 075131 (2022)