Mesoscale modelling of starch digestion

Molecular Physics Taylor & Francis ahead-of-print:ahead-of-print (2025) e2445770

Authors:

Muriel C van der Laan, John R Bows, Julia M Yeomans

Abstract:

An idealised mesoscale model of the enzymatic digestion of starch modelled as a polymer aggregate is used to study the effect of various enzyme properties, such as the enzyme efficiency, range and radius, on the rate at which monomers are released from the aggregate. Depending on the enzyme efficiency the process is found to be either reaction- or diffusion-limited. Additionally the digestion rate is found to be proportional to the volume around each bond that is accessible to the enzyme, which is determined by the range and radius of the enzyme. Simulations of uniformly mixed susceptible and resistant polymers reveal no significant effect on the digestion of the susceptible polymers due to the presence of the resistant polymers.

Phase separation in the putative fractional quantum hall A phases

Physical Review B: Condensed Matter and Materials Physics American Physical Society 111 (2025) 045102

Authors:

Steven Simon, Ajit Balram

Abstract:

We use several techniques to probe the wave functions proposed to describe the A phases by Das, Das, and Mandal [Phys. Rev. Lett. 131, 056202 (2023); Phys. Rev. Lett. 132, 106501 (2024); Phys. Rev. B 110, L121303 (2024).]. As opposed to representing fractional quantum Hall liquids, we find these wave functions to describe states that clearly display strong phase separation. In the process of exploring these wave functions, we have also constructed several new methods for diagnosing phase separation and generating such wave functions numerically. Finally, we uncover a new property of entanglement spectra that can be used as a check for the accuracy of numerics.

Fluctuation dissipation relations for active field theories

PHYSICAL REVIEW RESEARCH 7:3 (2025) ARTN L032053

Authors:

Martin Kjollesdal Johnsrud, Ramin Golestanian

Superconductivity from repulsive interactions in Bernal-stacked bilayer graphene

Physical Review B American Physical Society 110:21 (2024) 214517

Authors:

Glenn Wagner, Yves Kwan, Nick Bultinck, Steven Simon, Siddharth Ashok Parameswaran

Abstract:

A striking series of experiments have observed superconductivity in Bernal-stacked bilayer graphene (BBG) when the energy bands are flattened by applying an electrical displacement field. Intriguingly, superconductivity manifests only at nonzero magnetic fields, or when spin-orbit coupling is induced in BBG by coupling to a substrate. We present detailed functional renormalization group and random-phase approximation calculations that provide a unified explanation for the superconducting mechanism in both cases. Both calculations yield a purely electronic 𝑝-wave instability of the Kohn-Luttinger type. The latter can be enhanced either by magnetic fields or Ising spin-orbit coupling, naturally explaining the behavior seen in experiments.

Islands, Double Holography, and the Entanglement Membrane

arXiv: 2412.15070

Authors:

Hanzhi Jiang, Mike Blake, Anthony P. Thompson

Abstract:

The quantum extremal island rule allows us to compute the Page curves of Hawking radiation in semi-classical gravity. In this work, we study the connection between these calculations and the thermalisation of chaotic quantum many-body systems, using a coarse-grained description of entanglement dynamics known as the entanglement membrane. Starting from a double-holographic model of eternal two-sided asymptotically AdS_d (d>2) black hole each coupled to a flat d-dimensional bath, we show that the entanglement dynamics in the late-time, large-subregion limit is described by entanglement membrane, thereby establishing a quantitative equivalence between a semi-classical gravity and a chaotic quantum many-body system calculation of the Page curve.