---
_id: '8999'
abstract:
- lang: eng
  text: "In many basic shear flows, such as pipe, Couette, and channel flow, turbulence
    does not\r\narise 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. "
acknowledgement: "This research was funded by the Central Research Development Fund
  of the University of\r\nBremen grant number ZF04B /2019/FB04 Avila_Kerstin (“Independent
  Project for Postdocs”). Shreyas Jalikop is acknowledged for recording some of the
  lifetime measurements\r\n"
article_number: '58'
article_processing_charge: No
article_type: original
author:
- first_name: Kerstin
  full_name: Avila, Kerstin
  id: fcf74381-53e1-11eb-a6dc-b0e2acf78757
  last_name: Avila
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Avila K, Hof B. Second-order phase transition in counter-rotating taylor-couette
    flow experiment. <i>Entropy</i>. 2021;23(1). doi:<a href="https://doi.org/10.3390/e23010058">10.3390/e23010058</a>
  apa: Avila, K., &#38; Hof, B. (2021). Second-order phase transition in counter-rotating
    taylor-couette flow experiment. <i>Entropy</i>. MDPI. <a href="https://doi.org/10.3390/e23010058">https://doi.org/10.3390/e23010058</a>
  chicago: Avila, Kerstin, and Björn Hof. “Second-Order Phase Transition in Counter-Rotating
    Taylor-Couette Flow Experiment.” <i>Entropy</i>. MDPI, 2021. <a href="https://doi.org/10.3390/e23010058">https://doi.org/10.3390/e23010058</a>.
  ieee: K. Avila and B. Hof, “Second-order phase transition in counter-rotating taylor-couette
    flow experiment,” <i>Entropy</i>, vol. 23, no. 1. MDPI, 2021.
  ista: Avila K, Hof B. 2021. Second-order phase transition in counter-rotating taylor-couette
    flow experiment. Entropy. 23(1), 58.
  mla: Avila, Kerstin, and Björn Hof. “Second-Order Phase Transition in Counter-Rotating
    Taylor-Couette Flow Experiment.” <i>Entropy</i>, vol. 23, no. 1, 58, MDPI, 2021,
    doi:<a href="https://doi.org/10.3390/e23010058">10.3390/e23010058</a>.
  short: K. Avila, B. Hof, Entropy 23 (2021).
date_created: 2021-01-10T23:01:17Z
date_published: 2021-01-01T00:00:00Z
date_updated: 2023-08-07T13:31:07Z
day: '01'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.3390/e23010058
external_id:
  isi:
  - '000610135400001'
  pmid:
  - '33396499'
file:
- access_level: open_access
  checksum: 3ba3dd8b7eecff713b72c5e9ba30d626
  content_type: application/pdf
  creator: dernst
  date_created: 2021-01-11T07:50:32Z
  date_updated: 2021-01-11T07:50:32Z
  file_id: '9003'
  file_name: 2021_Entropy_Avila.pdf
  file_size: 9456389
  relation: main_file
  success: 1
file_date_updated: 2021-01-11T07:50:32Z
has_accepted_license: '1'
intvolume: '        23'
isi: 1
issue: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
pmid: 1
publication: Entropy
publication_identifier:
  eissn:
  - 1099-4300
publication_status: published
publisher: MDPI
quality_controlled: '1'
scopus_import: '1'
status: public
title: Second-order phase transition in counter-rotating taylor-couette flow experiment
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 23
year: '2021'
...
---
_id: '9020'
abstract:
- lang: eng
  text: '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. '
acknowledgement: "A.K. was supported by NSF grants DMR-2037654. T.G. acknowledges
  funding from the Institute of Science and Technology (IST) Austria, and from the
  European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie
  Grant Agreement No. 754411.\r\nWe are indebted to Boris Shklovskii for introducing
  us to the problem, and Alexander Gorsky and Peter Koroteev for introducing us to
  the Picard-Fuchs methods. A very special thanks goes to Michael Janas for several
  years of excellent collaboration on these topics. TG thanks Michael Kreshchuk for
  introduction to the exact WKB method and great collaboration on related projects.
  Figure 3 and Figure 4 are reproduced from Reference [25] with friendly permission
  by the Russian Academy of Sciences. Figure 2, Figure 4, Figure 5, Figure 6, and
  Figure 8 are reproduced from Reference [26] with friendly permission by IOP Publishing."
article_number: e23010125
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Tobias
  full_name: Gulden, Tobias
  id: 1083E038-9F73-11E9-A4B5-532AE6697425
  last_name: Gulden
  orcid: 0000-0001-6814-7541
- first_name: Alex
  full_name: Kamenev, Alex
  last_name: Kamenev
citation:
  ama: Gulden T, Kamenev A. Dynamics of ion channels via non-hermitian quantum mechanics.
    <i>Entropy</i>. 2021;23(1). doi:<a href="https://doi.org/10.3390/e23010125">10.3390/e23010125</a>
  apa: Gulden, T., &#38; Kamenev, A. (2021). Dynamics of ion channels via non-hermitian
    quantum mechanics. <i>Entropy</i>. MDPI. <a href="https://doi.org/10.3390/e23010125">https://doi.org/10.3390/e23010125</a>
  chicago: Gulden, Tobias, and Alex Kamenev. “Dynamics of Ion Channels via Non-Hermitian
    Quantum Mechanics.” <i>Entropy</i>. MDPI, 2021. <a href="https://doi.org/10.3390/e23010125">https://doi.org/10.3390/e23010125</a>.
  ieee: T. Gulden and A. Kamenev, “Dynamics of ion channels via non-hermitian quantum
    mechanics,” <i>Entropy</i>, vol. 23, no. 1. MDPI, 2021.
  ista: Gulden T, Kamenev A. 2021. Dynamics of ion channels via non-hermitian quantum
    mechanics. Entropy. 23(1), e23010125.
  mla: Gulden, Tobias, and Alex Kamenev. “Dynamics of Ion Channels via Non-Hermitian
    Quantum Mechanics.” <i>Entropy</i>, vol. 23, no. 1, e23010125, MDPI, 2021, doi:<a
    href="https://doi.org/10.3390/e23010125">10.3390/e23010125</a>.
  short: T. Gulden, A. Kamenev, Entropy 23 (2021).
date_created: 2021-01-19T11:12:06Z
date_published: 2021-01-19T00:00:00Z
date_updated: 2023-08-07T13:34:18Z
day: '19'
ddc:
- '530'
department:
- _id: MaSe
doi: 10.3390/e23010125
ec_funded: 1
external_id:
  arxiv:
  - '2012.01390'
  isi:
  - '000610122000001'
file:
- access_level: open_access
  checksum: 6cd0e706156827c45c740534bd32c179
  content_type: application/pdf
  creator: tgulden
  date_created: 2021-01-19T11:11:14Z
  date_updated: 2021-01-19T11:11:14Z
  file_id: '9021'
  file_name: Final published paper.pdf
  file_size: 981285
  relation: main_file
file_date_updated: 2021-01-19T11:11:14Z
has_accepted_license: '1'
intvolume: '        23'
isi: 1
issue: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Entropy
publication_identifier:
  eissn:
  - 1099-4300
publication_status: published
publisher: MDPI
quality_controlled: '1'
status: public
title: Dynamics of ion channels via non-hermitian quantum mechanics
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 23
year: '2021'
...