Posts by Collection

Quantum scars and bulk coherence in a symmetry-protected topological phase

Published in Physical Review B, 2021

Formation of quantum scars in many-body systems provides a novel mechanism for enhancing coherence of weakly entangled states. At the same time, coherence of edge modes in certain symmetry-protected topological (SPT) phases can persist away from the ground state. In this work we show the existence of many-body scars and their implications on bulk coherence in such an SPT phase. Read more

Recommended citation: Jared Jeyaretnam, Jonas Richter, Arijeet Pal, "Quantum scars and bulk coherence in a symmetry-protected topological phase." Physical Review B, 2021.
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Renormalization view on resonance proliferation between many-body localized phases

Published in Physical Review B, 2023

Topology and many-body localization (MBL) have opened new avenues for preserving quantum information at finite energy density. Resonant delocalization plays a crucial role in destabilizing these phenomena. In this paper, we study the statistical properties of many-body resonances in a disordered interacting Ising model—which can host symmetry-protected topological order—using a Clifford circuit encoding of the real-space renormalization group which allows the resonant properties of the wave functions to be efficiently characterized. Read more

Recommended citation: Jared Jeyaretnam, Christopher Turner, Arijeet Pal, "Renormalization view on resonance proliferation between many-body localized phases." Phys. Rev. B, 2023.
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Ergodicity breaking and stabilisation of quantum order (PhD Thesis)

Published in University College London, 2023

Supervisor: Arijeet Pal At zero temperature, symmetry-protected topological (SPT) order can encode quantum information in an edge strong zero mode, robust to perturbations respecting some symmetry. On the other hand, phenomena like many-body localisation (MBL) and quantum scarring can arrest the approach to thermal equilibrium, contrary to the ergodic dynamics expected of generic quantum systems. This raises the possibility that by combining SPT order with such ergodicity breaking phenomena, one might be able to construct a quantum memory that is robust at finite temperature. However, MBL is threatened by thermal avalanches due to rare low-disorder grains, while the survival of quantum scars in the thermodynamic limit is still uncertain beyond certain finely-tuned models. Read more

Recommended citation: Jared Jeyaretnam, "Ergodicity breaking and stabilisation of quantum order (PhD Thesis)." University College London, 2023.
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Hilbert space fragmentation at the origin of disorder-free localization in the lattice Schwinger model

Published in Communications Physics, 2025

Featured selection for April 2025! Lattice gauge theories, the discrete counterparts of continuum gauge theories, provide a rich framework for studying non-equilibrium quantum dynamics. Recent studies suggest disorder-free localization in the lattice Schwinger model, but its origin remains unclear. Using a combination of analytical and numerical methods, we show that Hilbert space fragmentation emerges in the strong coupling limit, constraining particle dynamics and causing sharp jumps in entanglement entropy growth within charge sectors. Read more

Recommended citation: Jared Jeyaretnam, Tanmay Bhore, Jesse Osborne, Jad Halimeh, Zlatko Papic, "Hilbert space fragmentation at the origin of disorder-free localization in the lattice Schwinger model." Commun. Phys. 8 172, 2025.
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Localisation and Hilbert Space Fracture in Lattice Gauge Theories

Published: June 24, 2024

Lattice gauge theories serve as a powerful model for understanding the continuous gauge field theories which underpin our universe. Yet beyond their foundational significance, they are also a rich source of novel physics in their own right, and are realisable on today’s quantum simulators. Recent attention has been drawn to their potential to exhibit robust localization phenomena despite the absence of disorder and the presence of long-ranged interactions, which typically preclude localisation. Read more

UCL Computing Workshops

Undergrad courses, University College London, Department of Physics & Astronomy, 2020

At UCL, I assisted with teaching two different undergraduate computing courses: an introduction to programming course for first-year students, and a more advanced course on scientific computing for second-year students. For both, I assisted with the running of workshops, where students would work through exercises on their own and ask for help from demonstrators. Read more

UCL Problem-Solving Tutorials

Undergrad courses, University College London, Department of Physics & Astronomy, 2021

I assisted with tutorials two different courses at UCL, including leading individual sessions in my final year. For these I had to prepare and present example solutions to the problems, and answer questions from the students about course material. Read more