@article{8999,
  abstract     = {In many basic shear flows, such as pipe, Couette, and channel flow, turbulence does not
arise from an instability of the laminar state, and both dynamical states co-exist. With decreasing flow speed (i.e., decreasing Reynolds number) the fraction of fluid in laminar motion increases while turbulence recedes and eventually the entire flow relaminarizes. The first step towards understanding the nature of this transition is to determine if the phase change is of either first or second order. In the former case, the turbulent fraction would drop discontinuously to zero as the Reynolds number decreases while in the latter the process would be continuous. For Couette flow, the flow between two parallel plates, earlier studies suggest a discontinuous scenario. In the present study we realize a Couette flow between two concentric cylinders which allows studies to be carried out in large aspect ratios and for extensive observation times. The presented measurements show that the transition in this circular Couette geometry is continuous suggesting that former studies were limited by finite size effects. A further characterization of this transition, in particular its relation to the directed percolation universality class, requires even larger system sizes than presently available. },
  author       = {Avila, Kerstin and Hof, Björn},
  issn         = {1099-4300},
  journal      = {Entropy},
  number       = {1},
  publisher    = {MDPI},
  title        = {{Second-order phase transition in counter-rotating taylor-couette flow experiment}},
  doi          = {10.3390/e23010058},
  volume       = {23},
  year         = {2021},
}

@article{9020,
  abstract     = {We study dynamics and thermodynamics of ion transport in narrow, water-filled channels, considered as effective 1D Coulomb systems. The long range nature of the inter-ion interactions comes about due to the dielectric constants mismatch between the water and the surrounding medium, confining the electric filed to stay mostly within the water-filled channel. Statistical mechanics of such Coulomb systems is dominated by entropic effects which may be accurately accounted for by mapping onto an effective quantum mechanics. In presence of multivalent ions the corresponding quantum mechanics appears to be non-Hermitian. In this review we discuss a framework for semiclassical calculations for the effective non-Hermitian Hamiltonians. Non-Hermiticity elevates WKB action integrals from the real line to closed cycles on a complex Riemann surfaces where direct calculations are not attainable. We circumvent this issue by applying tools from algebraic topology, such as the Picard-Fuchs equation. We discuss how its solutions relate to the thermodynamics and correlation functions of multivalent solutions within narrow, water-filled channels. },
  author       = {Gulden, Tobias and Kamenev, Alex},
  issn         = {1099-4300},
  journal      = {Entropy},
  number       = {1},
  publisher    = {MDPI},
  title        = {{Dynamics of ion channels via non-hermitian quantum mechanics}},
  doi          = {10.3390/e23010125},
  volume       = {23},
  year         = {2021},
}