Nature of active forces in tissues: how contractile cells can form extensile monolayers

Authors:

Lakshmi Balasubramaniam, Amin Doostmohammadi, Thuan Beng Saw, Gautham Hari Narayana Sankara Narayana, Romain Mueller, Tien Dang, Minnah Thomas, Shafali Gupta, Surabhi Sonam, Alpha S Yap, Yusuke Toyama, René-Marc Mège, Julia Yeomans, Benoît Ladoux

New horizons for inhomogeneous quenches and Floquet CFT

arXiv:2404.07884

Authors:

Hanzhi Jiang, Márk Mezei

Abstract:

A fruitful avenue in investigating out-of-equilibrium quantum many-body systems is to abruptly change their Hamiltonian and study the subsequent evolution of their quantum state. If this is done once, the setup is called a quench, while if it is done periodically, it is called Floquet driving. We consider the solvable setup of a two-dimensional CFT driven by Hamiltonians built out of conformal symmetry generators: in this case, the quantum dynamics can be understood using two-dimensional geometry. We investigate how the dynamics is reflected in the holographic dual three-dimensional spacetime and find new horizons. We argue that bulk operators behind the new horizons are reconstructable by virtue of modular flow.

Non-Poissonian bursts in the arrival of phenotypic variation can strongly affect the dynamics of adaptation

Authors:

Nora S Martin, Steffen Schaper, Chico Q Camargo, Ard A Louis

Odd Fracton Theories, Proximate Orders, and Parton Constructions

Physical Review B: Condensed Matter and Materials Physics American Physical Society

Authors:

Michael Pretko, Sa Parameswaran, Michael Hermele

Abstract:

The Lieb-Schultz-Mattis (LSM) theorem implies that gapped phases of matter must satisfy non-trivial conditions on their low-energy properties when a combination of lattice translation and $U(1)$ symmetry are imposed. We describe a framework to characterize the action of symmetry on fractons and other sub-dimensional fractional excitations, and use this together with the LSM theorem to establish that X-cube fracton order can occur only at integer or half-odd-integer filling. Using explicit parton constructions, we demonstrate that "odd" versions of X-cube fracton order can occur in systems at half-odd-integer filling, generalizing the notion of odd $Z_2$ gauge theory to the fracton setting. At half-odd-integer filling, exiting the X-cube phase by condensing fractional quasiparticles leads to symmetry-breaking, thereby allowing us to identify a class of conventional ordered phases proximate to phases with fracton order. We leverage a dual description of one of these ordered phases to show that its topological defects naturally have restricted mobility. Condensing pairs of these defects then leads to a fracton phase, whose excitations inherit these mobility restrictions.

On thermal fluctuations in quantum magnets

Physical review B: Condensed matter and materials physics American Physical Society

Authors:

DA Tennant, S Notbohm, B Lake, AJA James, FHL Essler, H-J Mikeska, J Fielden, P Kögerler, PC Canfield, MTF Telling

Abstract:

The effect of thermal fluctuations on the dynamics of a gapped quantum magnet is studied using inelastic neutron scattering on copper nitrate, a model material for the one-dimensional (1D) bond alternating Heisenberg chain, combined with theoretical and numerical analysis. We observe and interpret the thermally induced central peak due to intraband scattering as well as the thermal development of an asymmetric continuum of scattering. We relate this asymmetric line broadening to hard core constraints and quasi-particle interactions. Our findings are a counter example to recent assertions of universality of line broadening in 1D systems and are to be considered as a new paradigm of behaviour, applicable to a broad range of quantum systems.