BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//SoPA UoE//Event Calendar//EN
X-WR-CALNAME:Statistical Physics and Complexity Group meeting
X-WR-CALDESC:Statistical Physics and Complexity Group meeting
X-PUBLISHED-TTL:PT12H
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VTIMEZONE
TZID:Europe/London
X-LIC-LOCATION:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
DTSTART:19810329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
TZNAME:BST
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19961027T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
TZNAME:GMT
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79524@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20190726T093830
LAST-MODIFIED:20190726T094104
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20190925T113000
DTEND;TZID=Europe/London:20190925T123000
SUMMARY:Temperature Interfaces in the Katz-Lebowitz-Spohn Driven Lattice G
as
DESCRIPTION:Authors: Ruslan I. Mukhamadiarov\, Priyanka\, Uwe C. Tauber\n
Department of Physics and Center for Soft Matter and Biological Physics\,\
n Virginia Tech\, Blacksburg\, VA\n We explore the intriguing spatial patt
erns that emerge in a two-dimensional \n spatially inhomogeneous Katz-Leb
owitz-Spohn (KLS) driven lattice gas with \n attractive nearest-neighbor
interactions. The domain is split into two \n regions with hopping rates
governed by different temperatures T > Tc and \n Tc\, respectively\, wher
e Tc indicates the critical temperature for phase \n ordering\, and with
the temperature boundaries oriented perpendicular to the \n drive. In the
hotter region\, the system behaves like the (totally) asymmetric\n exclus
ion processes (TASEP)\, and experiences particle blockage in front of \n
the interface to the critical region.\n To explain this particle density
\n accumulation near the interface\, we have measured the steady-state cur
rent in\n the KLS model at T > Tc and found it to decay as 1/T. In analogy
with TASEP \n systems containing "slow" bonds\, transport in the high-te
mperature subsystem \n is impeded by the lower current in the cooler regi
on\, which tends to set the \n global stationary particle current value.
This blockage is induced by the \n extended particle clusters\, growing l
ogarithmically with system size\, in the \n critical region. We observe t
he density profiles in both high-and low-\n temperature subsystems to be s
imilar to the well-characterized coexistence \n and maximal-current phase
s in (T)ASEP models with open boundary conditions\, \n which are respecti
vely governed by hyperbolic and trigonometric tangent \n functions. Yet i
f the lower temperature is set to Tc\, we detect marked \n fluctuation co
rrections to the mean-field density profiles\, e.g.\, the \n correspondin
g critical KLS power law density decay near the interfaces into \n the co
oler region. If the temperature interface is aligened parallel to the\n dr
ive\, we observe the cooler region to act as an absorbing sink for particl
e \n transport\, with blockages emerging at the subsystem boundaries.\n R
ef.: R.I. Mukhamadiarov\, Priyanka\, and U.C.T.\, arXiv:1907.08576\n Resea
rch was sponsored by the Army Research Office (ARO) and was accomplished\n
under Grant Number W911NF-17-1-0156.\n\nSpeaker:\n* Professor Uwe Tauber
(Virginia Tech)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79524-temperature-interfaces-in-th
e-katz-lebowitz-spohn-driven-lattice-gas
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79688@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191007T084430
LAST-MODIFIED:20191007T084430
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191009T113000
DTEND;TZID=Europe/London:20191009T123000
SUMMARY:RSB40 Conference update
DESCRIPTION:I will give an update on the conference "40 years of Replica S
ymmetry \n Breaking: A conference about systems with many states". I will
not \n discuss any of the technical details of replicas\, but will focus
on \n the interesting results obtained in areas like\n\nDeep neural netw
orks\n Statistical mechanics of protein evolution\n The glass transition\n
\n I will mention if the time the ongoing question of whether replica \n
symmetry breaking occurs in 3 dimensions.\n Slides and videos from the con
ference are available athttps://sites.google.com/view/rsb40/home\n\nSpeake
r:\n* Dr Peter Mottishaw (School of Physics & Astronomy\, University of Ed
inburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79688-rsb40-conference-update
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79675@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191002T163040
LAST-MODIFIED:20191002T163040
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191016T113000
DTEND;TZID=Europe/London:20191016T123000
SUMMARY:Dynamical fluctuation theory in a nutshell
DESCRIPTION:A dynamical fluctuation is an atypical value of a time-integra
ted observable such as entropy production\, particle current\, or number o
f state transitions in a stochastic system. A comprehensive theory exists
for how to characterize the likelihood of a dynamical fluctuation\, and to
determine the ensemble of system trajectories which realize it\, given th
at the observation times involved are large. In this talk I will explain t
he basic elements of this theory in the context of Markov jump processes.
While somewhat technical\, most of the developments can be made physically
intuitive by exploiting the clear analogy to ensemble theory in equilibri
um physics\, with distributions over microstates generalized to distributi
on of dynamical trajectories\, and the large N-limit replaced by the large
t-limit. In the following session we apply these tools to an analytically
solvable model. \n\nSpeaker:\n* Mr Emil Mallmin (School of Physics & Ast
ronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79675-dynamical-fluctuation-theory
-in-a-nutshell
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79676@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191002T170513
LAST-MODIFIED:20191021T144533
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191023T113000
DTEND;TZID=Europe/London:20191023T123000
SUMMARY:Dynamical fluctuations: a solved example
DESCRIPTION:In this talk I will apply the tools of dynamical large deviati
on theory introduced in the previous week's talk to a 1D asymmetric random
walk conditioned on spending a finite fraction of time at the origin. Thi
s problem was first studied by Nyawo & Touchette (PRE 98\, 052103 (2018))
in the continuum where they revealed a dynamical phase transition. At a c
ritical time-fraction\, there is a transition from trajectories localized
around the origin to trajectories which escape after some fraction of time
. The lattice version is solvable in closed form and is one of several mod
els examined in a recent publication of mine (J. Phys. A. 52 425002 (2019)
). \n\nSpeaker:\n* Mr Emil Mallmin (School of Physics & Astronomy\, Unive
rsity of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79676-dynamical-fluctuations-a-sol
ved-example
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79756@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191103T214145
LAST-MODIFIED:20191103T214222
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191106T113000
DTEND;TZID=Europe/London:20191106T123000
SUMMARY:The Hopfield model of neural networks
DESCRIPTION:I will use the Hopfield model as a common thread to review som
e aspects of the statistical mechanics of neural networks. Starting from t
he definition of the model and connection with spin glasses\, I will discu
ss it's representation as a restricted Boltzmann machine and how\, within
the latter representation\, one can witness the emergence of the layered s
tructure typical of deep learning methods.\n The talk will serve as a pres
entation of the reading group---another weekly meeting focused on an aspec
t of theoretical statistical mechanics.\n\nSpeaker:\n* Mr Francesco Cagnet
ta (School of Physics & Astronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79756-the-hopfield-model-of-neural
-networks
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79673@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191002T152605
LAST-MODIFIED:20191111T103632
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191113T113000
DTEND;TZID=Europe/London:20191113T123000
SUMMARY:Conference talks on turbulence and microswimmer collective behavio
ur
DESCRIPTION:Viktor Skultety and James Hitchen will give dry-runs of their
upcoming conference talks.\n\nJames' talk (~10 min):\n\nThe mechanism of l
ong turbulent lifetimes in a low-dimensional model of plane Couette flow\n
\nRecently\, our understanding of the transition to turbulence has signifi
cantly changed due to the discovery of exact solutions of the Navier-Stoke
s equations and the introduction of the self-sustaining process in paralle
l shear flows. This theory has been very successful in describing the main
features of weakly turbulent states\, including the metastable nature of
turbulence close to the transition and the super-exponential dependence of
its lifetime on the Reynolds number. The main strength of this approach i
s that it allows for a semi-analytical description of the turbulent dynami
cs in the form of a rather low-dimensional model. Here we systematically d
evelop a novel low-dimensional model that allows us to investigate the ori
gin of the very long turbulent life-times close to the transition. We find
that there exists a particular periodic orbit that acts as a porous refle
cting barrier between the laminar and turbulent states\, and that serves t
o greatly increase the time before relaminarisation.\n\nViktor's talk (~30
min):\n\nThe role of correlations in the collective behaviour of microswi
mmer suspensions\n\nThe main distinction of 'active matter' from its passi
ve counterpart is the ability to extract energy from the environment (cons
ume food) and convert it into directed motion. One of the most striking co
nsequences of this distinction is the appearance of collective motion in s
elf-propelled particles suspended in a fluid observed in recent experiment
s and simulations: at low densities particles move around in an uncorrelat
ed fashion\, while at higher densities they organise into jets and vortice
s comprising many individual swimmers. Although this problem received sign
ificant attention in recent years\, the precise origin of the transition i
s poorly understood. Here we present a novel kinetic theory that captures
correlations below the transition\, and is non-perturbative in the swimmer
density. We show that correlations cannot be neglected at any density.\n\
nSpeakers:\n* Mr Viktor Skultety (School of Physics & Astronomy\, Universi
ty of Edinburgh)\n* Mr James Hitchen (School of Physics & Astronomy\, Univ
ersity of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79673-conference-talks-on-turbulen
ce-and-microswimmer-collective-behaviour
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79817@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191119T153324
LAST-MODIFIED:20191119T153324
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191120T113000
DTEND;TZID=Europe/London:20191120T123000
SUMMARY:Breaking replica symmetry at two different temperatures
DESCRIPTION:I will provide a basic introduction to the idea an overlap dis
tribution to describe phase transitions in disordered systems and for a si
mple problem show how this can be calculated using Parisi's replica symmet
ry breaking scheme. I will then summarise our current research on how thi
s can be extended to the overlap between 2 different temperatures. This re
search is in collaboration with Bernard Derrida.\n\nThe agenda.\n\n\n Intr
oduction to overlap distribution to describe phase transitions - ferromagn
et vs spin glass.\n \n \n Why we would like to know the overlap distributi
on between two different temperatures - chaos or not?\n \n \n Random energ
y model - the simplest non-trivial model.\n \n \n Overlap distribution in
the random energy model and 1 step replica symmetry breaking at a single t
emperature.\n \n \n Generalisation of the replica symmetry breaking scheme
to 2 temperatures.\n \n\n\nThe basic concepts of overlap distributions an
d replicas are discussed in Mézard\, M.\, Parisi\, G. and Virasoro\, M.\,
1987. Spin glass theory and beyond: An Introduction to the Replica Metho
d and Its Applications\n\nSpeaker:\n* Dr Peter Mottishaw (School of Physic
s & Astronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79817-breaking-replica-symmetry-at
-two-different-temperatures
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79795@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191111T124351
LAST-MODIFIED:20191127T101246
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191127T113000
DTEND;TZID=Europe/London:20191127T123000
SUMMARY:Extreme value distributions: the “max-stable distribution” app
roach
DESCRIPTION:The maximum of some large set of independent\, identically-dis
tributed random variables is known to approach one of three distributions
(Fréchet\, Gumbel or Weibull). In this talk\, I will show that these are\
, in fact\, special cases of a common distribution\, a fact that can be es
tablished from a self-similarity property known in the trade as “max sta
bility”. Time permitting\, I will also write down a recipe for determini
ng the large-N limiting forms\, since this is likely to be most useful in
applications.\n\nSpeaker:\n* Professor Richard Blythe (School of Physics &
Astronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79795-extreme-value-distributions-
the-max-stable-distribution-approach
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79870@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191202T214514
LAST-MODIFIED:20191202T214514
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191204T113000
DTEND;TZID=Europe/London:20191204T123000
SUMMARY:Continuous-time quantum walks
DESCRIPTION:Given a graph\, classical random walks evolve a probability di
stribution over its vertices. Quantum walks do the same but for wave funct
ions\, which are described by giving the wave's amplitude at each vertex.
A photon traversing an array of crystals is a physical example of a quantu
m walk. Here\, it's not just a particle walking a graph\, but a wave propa
gating through it and interfering with itself. Interference changes the be
haviour of the walk in surprising ways and it has been shown to provide po
werful computational advantages.\n\nIn this talk I'll introduce the topic
of continuous-time quantum walks. We will focus on studying the scattering
of wave packets on open graphs. The final goal is to explain Andrew M. Ch
ild's paper "Universal computation by quantum walk" (2009)\, which provide
s a method to execute any quantum computation (i.e. simulate any quantum e
volution) using quantum walks. If there's time left\, I will briefly discu
ss some of the algorithms that have been proposed using quantum walks.\n\n
Speaker:\n* Pablo Andres-Martinez (School of Informatics\, University of E
dinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79870-continuous-time-quantum-walk
s
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79674@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20191002T152858
LAST-MODIFIED:20191209T151111
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20191211T113000
DTEND;TZID=Europe/London:20191211T123000
SUMMARY:First-passage times of many persistent random walkers in higher di
mensions
DESCRIPTION:The field of active matter studies particles\, or collections
thereof\, which consume energy to perform motion. This defining property's
main consequence is the breaking of detailed balance: active systems are
inherently out of equilibrium\, and as such cannot be described by the Bol
tzmann distribution. With a general framework of non-equilibrium statistic
al mechanics lacking\, active-matter models serve as an effective means by
which we can develop our intuition for the former.\n\nOriginally inspired
by Escherichia coli bacteria\, one such set of models which have been hea
vily studied are run-and-tumble models. While much analytical work has bee
n conducted at a field-theoretic level\, almost all microscopic\, interact
ing run-and-tumble models are limited in particle number and are restricte
d to one dimension. Here\, we will first lift the latter restriction by pr
esenting an approximate solution to a two-particle first-passage problem i
n two dimensions. We will then extend this approach by generalising to N d
ilute particles in d dimensions\, and present evidence for clustering beha
viour even at very low densities.\n\nSpeaker:\n* Mr Matthew Metson (School
of Physics & Astronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2019/79674-first-passage-times-of-many-
persistent-random-walkers-in-higher-dimensions
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79948@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200127T182240
LAST-MODIFIED:20200127T182240
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200129T113000
DTEND;TZID=Europe/London:20200129T123000
SUMMARY:New year startup & maximum displacement calculation
DESCRIPTION:In the first statistical physics group meeting of the year\, M
atthew Metson will present a classic calculation: the statistics of the ma
ximum displacement achieved by a Brownian random walk. This example is mot
ivated by the current theme of the Reading Group\, extreme value statistic
s\, but will be a fully self-contained presentation. The other half of the
session will be an open discussion about the format and speakers in the s
tat-phys-group meetings going forward.\n\nSpeaker:\n* Mr Matthew Metson (S
chool of Physics & Astronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/79948-new-year-startup-maximum-dis
placement-calculation
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79959@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200131T165803
LAST-MODIFIED:20200131T165803
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200205T113000
DTEND;TZID=Europe/London:20200205T123000
SUMMARY:Eoin's Operational Researcher Internship
DESCRIPTION:I recently finished an internship with the Scottish Government
as an Operational Researcher. In this talk\, I will explain what Operatio
nal Research entails\, share some details on the model I was working on\,
talk about what skills a physicist can bring to the table\, and answer que
stions on my time there.\n\nSpeaker:\n* Mr Eoin Ó Laighléis (School of P
hysics & Astronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/79959-eoins-operational-researcher
-internship
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79976@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200206T133428
LAST-MODIFIED:20200206T133428
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200212T113000
DTEND;TZID=Europe/London:20200212T123000
SUMMARY:Ribosome dynamics in mRNA translation under steady and non-steady
state conditions
DESCRIPTION:Abstract: Recent advances in fluorescence imaging have made it
possible to track single ribosomes translating messenger RNA (mRNA) in vi
vo in real-time. These experiments are typically performed under non-stead
y state conditions\, yet most models of mRNA translation assume the steady
state. I will present a mathematical framework based on continuous-time r
andom walk for tracking individual ribosomes in the standard model of mRNA
translation\, the totally asymmetric simple exclusion process (TASEP). In
particular\, I will consider translation under these three conditions: tr
anslation starting from a newly produced mRNA\, translation in the steady
state and run-off translation after inhibition of translation initiation.\
n \n\nSpeaker:\n* Dr Juraj Szavits Nossan (School of Physics & Astronomy
\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/79976-ribosome-dynamics-in-mrna-tr
anslation-under-steady-and-non-steady-state-conditions
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79995@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200220T173156
LAST-MODIFIED:20200220T173156
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200226T113000
DTEND;TZID=Europe/London:20200226T123000
SUMMARY:First passage times for (persistent) random walkers: a mystery
DESCRIPTION:A random walker hops between sites of a lattice\, choosing a n
ew direction at each hop. A persistent random walker has a memory of its h
opping direction\, so the same direction may be used for multiple hops. In
both cases we can ask how long it takes for a particle to fall off the ed
ge of finite lattice: this defines a first passage problem. We find that t
he mean first-passage time\, starting from an edge of the lattice\, is the
same for a random walker and a persistent walker. This implies that rate
at which a persistent walker changes direction does not enter into this fi
rst-passage time. The reason why is (at present) a mystery\; with perhaps
a walker that interpolates between these two behaviours shedding some ligh
t (or not) on it...\n\nSpeaker:\n* Professor Richard Blythe (School of Phy
sics & Astronomy\, University of Edinburgh)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/79995-first-passage-times-for-pers
istent-random-walkers-a-mystery
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79966@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200131T170846
LAST-MODIFIED:20200227T093134
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200318T113000
DTEND;TZID=Europe/London:20200318T123000
SUMMARY:Current fluctuations in reset and run-and-tumble processes
DESCRIPTION:I will present work on current fluctuations in stochastic pro
cesses with resetting\, demonstrating in particular how phase transitions
in the large deviations can be understood via a mapping to the classic P
oland-Scheraga model for DNA denaturation [R. J. Harris and H. Touchette\
, J. Phys. A: Math. Theor. 50\, 10LT01 (2017)]. This approach can be ex
tended to treat the case where the dynamics between resets depends on the
value of a parameter fixed at the last reset and\, in this context\, I wi
ll briefly discuss the application to run-and-tumble models of bacterial
dynamics. Finally\, I will mention the recent development of a "Thermodyna
mic Uncertainty Relation" which applies for such run-and-tumble–type pr
ocesses [M. Shreshtha and R. J. Harris\, EPL (Europhysics Letters) 126\,
40007 (2019)].\n\nSpeaker:\n* Dr Rosemary Harris (Queen Mary University of
London)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/79966-current-fluctuations-in-rese
t-and-run-and-tumble-processes
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-79964@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200131T170508
LAST-MODIFIED:20200131T170508
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200401T113000
DTEND;TZID=Europe/London:20200401T123000
SUMMARY:TBA
DESCRIPTION:TBA\n\nSpeaker:\n* Dr Ludovic Berthier (Universite de Montpell
ier)
LOCATION:Room 2511\, JCMB
URL:https://www.ph.ed.ac.uk/events/2020/79964-tba
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80085@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200406T092105
LAST-MODIFIED:20200406T092105
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200408T113000
DTEND;TZID=Europe/London:20200408T123000
SUMMARY:Current fluctuations in reset and run-and-tumble processes
DESCRIPTION:I will present work on current fluctuations in stochastic\n pr
ocesses with resetting\, demonstrating in particular how phase\n transitio
ns in the large deviations can be understood via a mapping to the\n classi
c Poland-Scheraga model for DNA denaturation [R. J. Harris and H.\n Touche
tte\, J. Phys. A: Math. Theor. 50\, 10LT01 (2017)]. This approach can\n
be extended to treat the case where the dynamics between resets depends on
\n the value of a parameter fixed at the last reset and\, in this context\
, I\n will briefly discuss the application to run-and-tumble models of bac
terial\n dynamics. Finally\, I will mention the recent development of a\n
"Thermodynamic Uncertainty Relation" which applies for such\n run-and-tumb
le–type processes [M. Shreshtha and R. J. Harris\, EPL\n (Europhysics Le
tters) 126\, 40007 (2019)].\n\nSpeaker:\n* Dr Rosemary Harris (Queen Mary
University of London)
LOCATION:Online
URL:https://www.ph.ed.ac.uk/events/2020/80085-current-fluctuations-in-rese
t-and-run-and-tumble-processes
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80049@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200309T093743
LAST-MODIFIED:20200420T084826
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200422T113000
DTEND;TZID=Europe/London:20200422T123000
SUMMARY:Wrinkle patterns in active viscoelastic thin sheets
DESCRIPTION:We show that a viscoelastic thin sheet driven out of equilibri
um by active structural remodelling develops a rich variety of shapes as
a result of a competition between viscous relaxation and activity. In the
regime where active processes are faster than viscoelastic relaxation\, w
rinkles that are formed due to remodelling are unable to relax to a confi
guration that minimises the elastic energy and the sheet is inherently ou
t of equilibrium. We argue that this non-equilibrium regime is of particu
lar interest in biology as it allows the system to access morphologies tha
t are unavailable if restricted to the adiabatic evolution between config
urations that minimise the elastic energy alone. Here\, we introduce acti
vity using the formalism of an evolving target metric and showcase the div
ersity of wrinkling morphologies arising from out of equilibrium dynamics
. \n\nSpeaker:\n* Dr Rastko Sknepnek (University of Dundee)
LOCATION:Online
URL:https://www.ph.ed.ac.uk/events/2020/80049-wrinkle-patterns-in-active-v
iscoelastic-thin-sheets
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80099@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200426T102532
LAST-MODIFIED:20200426T102651
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200429T113000
DTEND;TZID=Europe/London:20200429T123000
SUMMARY:Will a large stable system be complex?
DESCRIPTION:We consider a first-order dynamical system where the NxN pairw
ise interaction matrix is random and sparse\, i.e. it is the (weighted) ad
jacency matrix of an underlying random graph. We focus on the transient be
haviour in the vicinity of a stationary point. The squared norm of the pop
ulation vector — averaged over the random graph ensemble and uniform ini
tial conditions — may exhibit a large degree of universality at short ti
mes. For oriented graphs\, we can universally characterise the transient b
ehaviour solely in terms of the average connectivity c\, the variance σ2
of the bond disorder\, and simple spectral properties (e.g. presence and l
ocation of outliers). Our predictions are numerically tested on a wide var
iety of graph topologies and bond disorder with excellent agreement\, as w
ell as on simulated first-order dynamics on small empirical networks. On t
he technical side\, the results follow from the calculation of a Dunford-T
aylor integral over the two-point resolvent of random graphs\, which can b
e efficiently computed for large N using the celebrated ‘cavity method
’ — borrowed from the physics of disordered systems.\n\nJoint work wit
h Izaak Neri (King's College London) and Wojciech Tarnowski (Krakow). [htt
ps://arxiv.org/abs/1906.10634]\n\nSpeaker:\n* Dr Pierpaolo Vivo (Dept of M
athematics\, King's College London)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80099-will-a-large-stable-system-b
e-complex
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80221@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200507T181754
LAST-MODIFIED:20200511T094357
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200513T113000
DTEND;TZID=Europe/London:20200513T123000
SUMMARY:Speed-dispersion-induced alignment: A one-dimensional model inspir
ed by swimming droplets experiments
DESCRIPTION:Richard will discuss the paper:\n\nSpeed-dispersion-induced al
ignment: A one-dimensional model inspired by swimming droplets experim
ents\n\nby Illien et al (2020) Physical Review E 101\, 040602(R)\n\nDetai
ls of talk:\n\nThis paper outlines some experiments of out-of-equilibrium
water droplets that are confined to a one-dimensional channel\, have an ex
cluded volume interaction and collide inelastically. A model of the observ
ed dynamics demonstrates that an interplay between activity and the inelas
tic collisions leads to macroscopic alignment when (i) the energy lost in
collisions is high and (ii) the rate at which particles return to their us
ual speed is low. It also suggests the transient appearance of condensates
at the earlier stages of the alignment process. This system is of interes
t as it combines aspects of persistent exclusion processes (aka run-and-tu
mble) and flocking models.\n\nSpeaker:\n* Professor Richard Blythe (School
of Physics & Astronomy\, University of Edinburgh)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80221-speed-dispersion-induced-ali
gnment-a-one-dimensional-model-inspired-by-swimming-droplets-experiments
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80222@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200507T181905
LAST-MODIFIED:20200518T101033
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200520T113000
DTEND;TZID=Europe/London:20200520T123000
SUMMARY:Steady-state currents in active matter: origin and implications
DESCRIPTION:It is well known that under rather generic circumstances activ
e systems can generate currents due to\, say\, an external potential. In t
he talk\, I will discuss several implications of this fact on the physics
of different systems. Specifically\, I will focus on interactions between
objects immersed in an active fluid\, the effects of disorder on active pa
rticles\, and escape problems.\n\nSpeaker:\n* Professor Yariv Kafri (Techn
ion)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80222-steady-state-currents-in-act
ive-matter-origin-and-implications
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80215@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200502T175822
LAST-MODIFIED:20200519T093848
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200527T113000
DTEND;TZID=Europe/London:20200527T123000
SUMMARY:On the largest eigenvalue of a random matrix: Tracy-Widom distribu
tion\, large deviations and third order phase transition.
DESCRIPTION:The statistical properties of the largest eigenvalue $\\lambda
_{\\max}$ of a random matrix are of interest in diverse fields such as in
the stability of large ecosystems\, in disordered systems and related st
ochastic growth processes\, in statistical data analysis and even in stri
ng theory. In this talk I will review the developments in the theory of t
he fluctuations of $\\lambda_{\\max}$ in the classical Gaussian ensembles
of Random Matrix Theory -- such as the Gaussian Orthogonal Ensemble. In
the limit of large matrix size $N$\, the probability density function (PD
F) $\\lambda_{\\max}$ consists of a central part described by the celebra
ted Tracy-Widom distribution flanked\, on both sides\, by two large devia
tions tails. While the central part characterizes the typical fluctuati
ons of $\\lambda_{\\max}$\, the large deviations tails are instead asso
ciated to extremely rare fluctuations. I will discuss in particular the t
hird-order phase transition which separates the left tail from the right t
ail\, a transition akin to the so-called Gross-Witten-Wadia phase trans
ition found in 2-d lattice quantum chromodynamics. If time permits\, I wi
ll discuss the occurrence of similar third-order transitions in various
physical problems\, such as the Sardar-Parisi-Zhang equation in $1+1$ di
mensions. \n\nSpeaker:\n* Dr Gregory Schehr (Université de Paris-Sud)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80215-on-the-largest-eigenvalue-of
-a-random-matrix-tracy-widom-distribution-large-deviations-and-third
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80223@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200507T182701
LAST-MODIFIED:20200527T093235
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200603T113000
DTEND;TZID=Europe/London:20200603T123000
SUMMARY:Some exact results on continuous-time quantum walks
DESCRIPTION: Quantum analogs of classical random walks have been defined
in quantum information theory as a useful concept to implement algorit
hms. Due to interference effects\, statistical properties of quantum
walks can drastically differ from their classical counterparts\, leading
to much faster computations.\n \n In this talk\, we shall discuss
various statistical properties of continuous-time quantum walks on a
lattice\, such as: survival properties of quantum particles in the pr
esence of traps\, the growth of a quantum population in the presence
of a source\, and quantum return probabilities (Loschmidt echoes).\n\nS
peaker:\n* Kirone Mallick (CEA Saclay)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80223-some-exact-results-on-contin
uous-time-quantum-walks
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80250@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200526T134546
LAST-MODIFIED:20200526T134546
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200610T113000
DTEND;TZID=Europe/London:20200610T123000
SUMMARY:Dynamical Large Deviations of Reflected Diffusions
DESCRIPTION:In this talk I discuss the calculation of the large deviation
functions characterizing the fluctuations of dynamical observables of Mark
ov diffusions with reflecting boundaries. In practice\, these large deviat
ion functions are often found via a spectral calculation. The proper bound
ary conditions for this spectral calculation in the presence of reflecting
boundaries is discussed\, and the implications for the driven process (wh
ich describes how fluctuations arise in the long-time limit) are explored.
As an illustration of our results\, I will discuss two particular applica
tions (reflected Ornstein-Uhlenbeck process and reflected Brownian motion
with drift). Finally\, I mention open problems and possible extensions of
this work. \n\nSpeaker:\n* Johan du Buisson (Stellenbosch University\, De
partment of Physics)
URL:https://www.ph.ed.ac.uk/events/2020/80250-dynamical-large-deviations-o
f-reflected-diffusions
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80234@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200513T161021
LAST-MODIFIED:20200611T135128
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200617T113000
DTEND;TZID=Europe/London:20200617T123000
SUMMARY:Bringing together two paradigms of non-equilibrium: Driven dynamic
s of aging systems
DESCRIPTION:Non-equilibrium behaviour can be broadly split into two catego
ries. The first is aging\, where a system can in principle reach an equi
librium state but its slow dynamics leads to extremely long transients dur
ing which the properties of the system depend on its age since preparation
. In the second category are driven systems\, whose dynamics breaks detail
ed balance leading to non-equilibrium steady states. An attractive way of
constructing descriptions of such driven systems is based on maximum entro
py arguments in trajectory space\, leading to so-called biased trajectory
ensembles.\n In this talk I will describe how these two non-equilibrium sc
enarios interact\, by studying the bias-driven dynamics of two simple mode
ls that are inspired by the physics of glasses and exhibit aging at low te
mperatures. The analysis allows one to detect dynamical phase transitions
that reveal unexpected qualitative differences in the robustness of aging
to additional driving.\n\nSpeaker:\n* Professor Peter Sollich (Universitä
t Göttingen\, Institut für Theoretische Physik)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80234-bringing-together-two-paradi
gms-of-non-equilibrium-driven-dynamics-of-aging-systems
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80231@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200512T181215
LAST-MODIFIED:20200618T100731
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200624T113000
DTEND;TZID=Europe/London:20200624T123000
SUMMARY:Flagellar length control in biflagellate eukaryotes: time-of-fligh
t\, shared pool\, train traffic and cooperative phenomena
DESCRIPTION:Flagella of eukaryotic cells are transient long cylindrical pr
otrusions. Very recently we have developed a stochastic model for flagell
ar length control based on a time-of-flight (ToF) mechanism. The proteins
needed to form and maintain flagella are synthesized in the cell body an
d transported to the distal tips by Intra-flagellar transport (IFT) train
s. We represent the traffic of IFT trains as a totally asymmetric simple
exclusion process (TASEP). The ToF mechanism for each flagellum\, togeth
er with the TASEP-based description of the IFT trains\, combined with a
scenario of sharing of a common pool of flagellar structural proteins in
biflagellates\, can account for all key features of experimentally known
phenomena. These include ciliogenesis\, resorption\, deflagellation as w
ell as regeneration after selective amputation of one of the two flagella
. Moreover\, we make new predictions on the flagellar length fluctuations
and the role of the common pool.\n\nSpeaker:\n* Professor Debashish Chow
dhury FNA\, FASc\, FNASc (Department of Physics\, Indian Institute of Tech
nology\, Kanpur 208016\, India)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80231-flagellar-length-control-in-
biflagellate-eukaryotes-time-of-flight-shared-pool-train-traffic-and
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80252@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200526T135145
LAST-MODIFIED:20200526T135145
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200701T113000
DTEND;TZID=Europe/London:20200701T123000
SUMMARY:Numerical computation and estimation of large deviations
DESCRIPTION:I will give in this talk a basic overview of numerical methods
developed recently for computing large deviation functions characterizing
the fluctuations of observables of Markov processes\, which are used in s
tatistical physics to model nonequilibrium processes. I will focus on two
methods - direct diagonalization and importance sampling - to explain how
the estimation of large deviations relates in general to optimal control t
heory\, and what differences or difficulties arise when treating reversibl
e vs non-reversible processes. I will end by discussing pros and cons of d
ifferent numerical methods\, as well as problems that remain in the field
of numerical large deviations.\n\nSpeaker:\n* Professor Hugo Touchette (St
ellenbosch University\, Department of Mathematical Sciences)
URL:https://www.ph.ed.ac.uk/events/2020/80252-numerical-computation-and-es
timation-of-large-deviations
END:VEVENT
BEGIN:VEVENT
CLASS:PUBLIC
UID:EVENT-80229@www.ph.ed.ac.uk
DTSTAMP:20200704T135835
CREATED:20200511T100859
LAST-MODIFIED:20200702T094222
STATUS:CONFIRMED
DTSTART;TZID=Europe/London:20200708T113000
DTEND;TZID=Europe/London:20200708T123000
SUMMARY:Absolute Negative Mobility: can it take place in thermal equilibri
um?
DESCRIPTION:Absolute Negative Mobility (ANM) is a phenomenon whereby curre
nt in a stationary system is in a direction opposite to the driving fi
eld. Naïve argument suggests that ANM cannot take place in systems in th
ermal equilibrium as this could lead to a violation of the second law of
thermodynamics. Thus numerous previous theoretical and experimental studie
s of ANM have dealt with the response to a driving field in nonequilibriu
m steady states. In this talk a simple lattice model of a driven trace
r is introduced and demonstrated to exhibit ANM in equilibrium\, with no
violation of the basic laws of thermodynamics. The limits of validity o
f the naïve argument are elucidated and the entropy production which acc
ompany the motion of the tracer is calculated.\n\nSpeaker:\n* David Mukame
l (Department of Physics of Complex Systems Weizmann Institute of Science
Israel)
LOCATION:Online - see email.
URL:https://www.ph.ed.ac.uk/events/2020/80229-absolute-negative-mobility-c
an-it-take-place-in-thermal-equilibrium
END:VEVENT
END:VCALENDAR