Scaling and localization in multipole-conserving diffusion
Abstract: We study diffusion in systems of classical particles whose dynamics conserves the total center of mass. This conservation law leads to several interesting consequences. In finite systems, it allows for equilibrium distributions that are exponentially localized near system boundaries. It also yields an unusual approach to equilibrium, which in $d$ dimensions exhibits scaling with dynamical exponent $z = 4+d$. Similar phenomena occur for dynamics that conserves higher moments of the density, which we systematically classify using a family of nonlinear diffusion equations. In the quantum setting, analogous fermionic systems are shown to form real-space Fermi surfaces, while bosonic versions display a real-space analog of Bose-Einstein condensation.
- S. Pai, M. Pretko, and R. M. Nandkishore, Localization in fractonic random circuits, Physical Review X 9, 021003 (2019).
- V. Khemani, M. Hermele, and R. Nandkishore, Localization from hilbert space shattering: From theory to physical realizations, Physical Review B 101, 174204 (2020).
- J. Iaconis, A. Lucas, and R. Nandkishore, Multipole conservation laws and subdiffusion in any dimension, Physical Review E 103, 022142 (2021).
- X. Feng and B. Skinner, Hilbert space fragmentation produces an effective attraction between fractons, Physical Review Research 4, 013053 (2022).
- M. Pretko, Subdimensional particle structure of higher rank u (1) spin liquids, Physical Review B 95, 115139 (2017).
- A. Prem, M. Pretko, and R. M. Nandkishore, Emergent phases of fractonic matter, Physical Review B 97, 085116 (2018).
- M. Pretko, The fracton gauge principle, Physical Review B 98, 115134 (2018).
- A. Gromov, A. Lucas, and R. M. Nandkishore, Fracton hydrodynamics, Physical Review Research 2, 033124 (2020).
- S. Sachdev, K. Sengupta, and S. Girvin, Mott insulators in strong electric fields, Physical Review B 66, 075128 (2002).
- E. Lake, M. Hermele, and T. Senthil, Dipolar bose-hubbard model, Phys. Rev. B 106, 064511 (2022).
- C. Stahl, E. Lake, and R. Nandkishore, Spontaneous breaking of multipole symmetries, Physical Review B 105, 155107 (2022).
- E. Lake and T. Senthil, Non-fermi liquids from kinetic constraints in tilted optical lattices, arXiv preprint arXiv:2302.08499 (2023).
- A. Anakru and Z. Bi, Non-fermi liquids from dipolar symmetry breaking, arXiv preprint arXiv:2304.01181 (2023).
- S. A. Chen, J.-K. Yuan, and P. Ye, Fractonic superfluids. ii. condensing subdimensional particles, Physical Review Research 3, 013226 (2021).
- J.-K. Yuan, S. A. Chen, and P. Ye, Fractonic superfluids, Physical Review Research 2, 023267 (2020).
- A. Glodkowski, F. Pena-Benitez, and P. Surowka, Hydrodynamics of dipole-conserving fluids, Physical Review E 107, 034142 (2023).
- Note that ordinary diffusion equation can be rewritten in a similar form as ∂tρ=−∂xJsubscript𝑡𝜌subscript𝑥𝐽\partial_{t}\rho=-\partial_{x}J∂ start_POSTSUBSCRIPT italic_t end_POSTSUBSCRIPT italic_ρ = - ∂ start_POSTSUBSCRIPT italic_x end_POSTSUBSCRIPT italic_J with J=−Dρ∂xln(ρ)𝐽𝐷𝜌subscript𝑥𝑙𝑛𝜌J=-D\rho\partial_{x}\mathop{ln}\nolimits(\rho)italic_J = - italic_D italic_ρ ∂ start_POSTSUBSCRIPT italic_x end_POSTSUBSCRIPT start_BIGOP italic_l italic_n end_BIGOP ( italic_ρ ).
- A. Morningstar, V. Khemani, and D. A. Huse, Kinetically constrained freezing transition in a dipole-conserving system, Physical Review B 101, 214205 (2020).
- The results of direct scaling of density fields with the dynamic exponents are also presented in SI [32].
- A. Lefèvre and G. Biroli, Dynamics of interacting particle systems: stochastic process and field theory, Journal of Statistical Mechanics: Theory and Experiment 2007, P07024 (2007).
- J. Guo, P. Glorioso, and A. Lucas, Fracton hydrodynamics without time-reversal symmetry, Physical Review Letters 129, 150603 (2022).
- The FDT holds for multipole-constrained diffusive system as well, being as it is applicable to any near-equilibrium situation.
- P. Borwein, Computational excursions in analysis and number theory (Springer Science & Business Media, 2002).
- A. Gromov, Towards classification of fracton phases: the multipole algebra, Physical Review X 9, 031035 (2019).
- D. Bulmash, O. Hart, and R. Nandkishore, Multipole groups and fracton phenomena on arbitrary crystalline lattices, arXiv preprint arXiv:2301.10782 (2023).
- R. Soto and R. Golestanian, Run-and-tumble dynamics in a crowded environment: Persistent exclusion process for swimmers, Physical Review E 89, 012706 (2014).
- G. E. Crooks, On thermodynamic and microscopic reversibility, Journal of Statistical Mechanics: Theory and Experiment 2011, P07008 (2011).
- I. G. Macdonald, Symmetric functions and Hall polynomials (Oxford university press, 1998).
- The nonlinearity measured by m𝑚mitalic_m discussed here refers to the largest power of the density appearing on the RHS of the master equation. When the hopping process is such that at most one particle hops from any given site, all terms on the RHS will be of the same order. In other cases (such as the 3-site dipole hopping process discussed in App. II) smaller powers may additionally appear. In this appendix we are interested in determining the minimal value that the largest power on the RHS can be.
Paper Prompts
Sign up for free to create and run prompts on this paper using GPT-5.
Top Community Prompts
Collections
Sign up for free to add this paper to one or more collections.