Complex Systems Studies
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@ComplexSys

#complexity #complex_systems #networks #network_science

📨 Contact us: @carimi
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Graph Limits and Processes on Networks: From Epidemics to Misinformation Boot Camp
Aug 29, 2022 to Sep 2, 2022

https://simons.berkeley.edu/workshops/graph2022-bc

The boot camp is intended to acquaint program participants with the key themes of the program. It will consist of five days of tutorial presentations from leading experts in the topics of the program.
Fixed-term position for a doctoral researcher/project researcher or research assistant in microbiome bioinformatics and data science

The Department of Computing at the University of Turku is searching for a doctoral researcher/project researcher or a research assistant in microbiome bioinformatics starting from 1.1.2023, or later according to a mutual agreement. This fixed-term position ends 28.2.2025. The position is full-time, but part-time work is also possible based on mutual understanding.

#phd https://rekry.saima.fi/certiahome/open_job_view.html?id=000013860&did=5600&lang=en&jc=14&nav_from_open_jobs_view_new=true
"Two days with Giorgio Parisi in Paris" - October 13-14, 2022

https://sites.google.com/view/parisiday-ens/home
Giorgio Parisi's scientific portray: Complex Systems and much more
Leticia F. Cugliandolo

https://t.co/zrsqcc1kwg

This article summarises the outstanding scientific career of Giorgio Parisi, who was awarded the 2021 Nobel Prize in Physics, with special emphasis on his contributions to the description of the equilibrium properties of disordered systems.
#PhD and #postdoc position at Saarland University.

’m building up a new “chair” (= research group) for Societal Computing at Saarland University (https://saarland-informatics-campus.de/en/). Societal Computing comprises both (i) computing _of_ society, i.e. the measurement and analysis of societal phenomena, and (ii) computing _for_ society, i.e. working with partners to improve things based on the obtained insights.
https://ingmarweber.de/publications/.

For my new group, I’m looking for motivated PhD students and postdocs who are enthusiastic about interdisciplinary data science with applications in these or similar areas. In terms of methodological expertise, I’m open for a range of profiles that include some computational experience. Of particular relevance is experience in studying societal phenomena using non-traditional data sources, such as social media, satellite imagery, or mobile phone records.

To qualify for a PhD student position, a MA/MSc in computer science or similar is required by the university. Applicants who hold only a BA/BSc are encouraged to get in touch. However, they will most likely be required to first take additional coursework.

To qualify for a postdoc position, a strong publication record is required. The publication record should include at least some work with an application to studying a societal issue.

All positions are 100% (in the German system) following the corresponding public pay scale. Specifics depend on marital status and other factors, but general information can be found at https://academicpositions.com/career-advice/phd-postdoc-and-professor-salaries-in-germany, https://fastepo.com/phd-and-postdocs-salary/phd-students-and-postdocs-salary-germany-2020/, or on similar websites.

To apply, please send a CV and, ideally, academic transcripts to ingmar.weber@uni-saarland.de

Applications will be considered on a rolling basis until positions are filled. For full consideration please apply by Sunday, September 11.

Ingmar Weber
Forwarded from Brain science journal club (Ali Vali)
سلام به همگی. بعد از یه رخوت شش ماهه کار مقاله‌خوانی رو از سر گرفتیم و امیدوارم این‌بار منقطع نشه. تو این دوره هرچند ماه یک تم برای مقاله‌ها در نظر میگیریم که شاید مفیدتر بشه. تم چند ماه آینده بیماری آلزایمر خواهد بود و سعی میکنیم مقالات مهم رو در حدود یک دهه اخیر مرور کنیم. این مقالات قبل از اینکه اینجا ارایه بشن، سه‌شنبه‌ها در جلساتی که در موسسه رهیافت برگزار میشه بررسی میشن. من خیلی دوست دارم که کانال یوتیوبی هم که داریم فعال بشه که البته با شرایط اینترنت موجود کار آسونی نیست. از پیشنهادات دوستان استقبال میکنیم.
Four #postdoc/research fellow positions in complex networks at the Czech Academy of Sciences in Prague
cobra.cs.cas.cz
I am currently looking for a #phd student to investigate the impact of network structures, interventions, and ranking algorithms on collective social behavior.

https://www.socialnetworks.uzh.ch/en/no-open-positions.html
Three open positions in data science & AI/ML methods and applications at Dpt of Computing, Turku, Finland for #PhD / project researcher / assistant.

1) Scientific data analysis; DL Sep 30.
2) Microbiome & metagenome research; DL Sep 19
3) Computational humanities; DL Sep 30
I am happy to announce that I made a group for all Persian Kagglists around the globe. I made this group wishing to gather all Persian Kagglist and interested people under the same roof. Communication is the key! This group would help people to find and know each other. This will also help to increase the chance of being seen for finding a desired data science job. Please spread the word. Thanks!
#kaggle #datascience
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AI4Science #Call for fellows!
Deadline: Oct. 31, 2022

The #Fellowship gives researchers the chance to collaborate EPFL faculties on accelerating the use and furthering the understanding of #MachineLearning methods in the scientific discovery process. You hold a PhD, in any field relevant to this endeavour, are fluent in English and have a collaborative spirit.

https://www.epfl.ch/research/domains/cis/call-for-fellows/
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Spontaneous Symmetry Breaking
A little thread by Michael Sentef

Did you know that there was a connection to nonequilibrium physics?
Take a collection of bar magnets (it's all classical physics), with a force between neighboring ones that wants to align them with one another. We call this "ferromagnetic exchange". Now, each little magnet is free to rotate in space. So is the collective magnetization.

This is the energy of the system. x is the spatial location of the "spin", and delta is a vector connecting nearest neighbors. J is the ferromagnetic exchange interaction. The collective magnetization M is the sum of all spin vectors. As written above, the energy is minimal when all spins are aligned, and the modulus |M| is maximal then. But where will the M-vector point in space? This is *impossible* to predict from our theory. Why?

The energy functional written above does not tell us! This is precisely what we call spontaneous symmetry breaking. And this is what we all learn in our textbooks.

Now, here is a plot twist. We also learn in statistical mechanics how to compute thermal expectation values of stuff. Take all states (all possible spin configurations). Take their magnetization (=sum of little spins). Attach a "Boltzmann weight". Sum over all states. This statistical <M> value will always be zero! Why? Because the E-functional does not tell us which direction M should point into. There is no preferred direction.

In other words, stat-mech tells us that spontaneous symmetry breaking does not exist. Ummm... but you told us that it did, right? Also, how does my fridge magnet work if stat-mech forbids it to exist?

Here is an answer: We should consider the "thermodynamic limit". Which is "singular". How so? The prescription that we still all learn is the following: Pretend that there is a preferred direction, given by this little h-field (an "external magnetic field" -- where it comes from doesn't matter here).

Now all spins align with this h-field, and with one another. All problems solved? Not quite. We have to consider two limits. We can first let h->0 and then the number of little magnets N->infinity, or vice versa. The order of limits matters! (They do not "commute"). When we let h->0 for any finite system, <M> will be zero. When we first let N->infinity (the thermodynamic limit) and then h->0, <M> will remain finite and maximal, and will remember the direction in which h pointed originally. This is still all well known.

But here is a conundrum. We think of spontaneous symmetry breaking only in the thermodynamic limit. It is being taught like this everywhere. But ... nothing is infinite in nature! Yet we have fridge magnets, and they work! Why? Nonequilibrium comes to the rescue! How quickly does a fridge magnet de-magnetize after it has been magnetized? I.e., how does the limiting process in which we apply the h-field for a finite (but large) collection of spins, then turn the h-field off, work in real time? When the number of spins is large, they need to "fluctuate" away from the perfectly aligned configuration spontaneously in order to de-magnetize. This is increasingly unlikely when (a) the temperature is low and (b) N is large.

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The system does not explore its state space. More precisely, the state space is not explored according to the "Boltzmann weights" mentioned above. We call this behavior "non-ergodic". Relaxation to a non-magnetic configuration is super slow for your fridge magnet. Wait long enough, and it will fall off the fridge. But "long" means "almost till eternity", provided that the magnet is sufficiently strong and sufficiently large. This is what we mean by "thermodynamic limit" for all practical purposes. The time scale on which we see "thermalization" is really really large. Now, this was all somewhere in the back of my mind, but I never thought about it so clearly. Who did? These guys: Aron J. Beekman, Louk Rademaker, Jasper van Wezel. Props to Aron, Louk and Jasper for spelling out what one rarely finds spelled out in textbooks.
I highly recommend reading their lecture notes. I should do it as well.

https://twitter.com/sentefmi/status/1572463208262434817

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