Sóley Benediktsdóttir

Benedikt Magnússon, september 24, 2021

Menntun framhaldsskólakennara

Þróun verkefna um diffrun með áherslu á skilning og uppgötvun

Leiðbeinendur: Benedikt Steinar Magnússon og Bjarnheiður Kristinsdóttir
Prófdómari: Kristín Bjarnadóttir, Professor Emerita

Ágrip
Stærðfræðinám í framhaldsskólum reynist mörgum nemendum erfitt. Sumir nemendur gefast upp eða byrja að halda því fram að þeir geti ekki reiknað stærðfræði. Fyrir kennara er mikilvægt að sporna við slíku hugarfari. Rannsóknir sýna að ein besta leiðin til að hjálpa nemendum að finnast þeir hafa tök á stærðfræði sé að leyfa þeim að mynda eigin tengingar milli ólíkra efnisþátta stærðfræðinnar og að uppgötva sjálfir stærðfræðilegar hugmyndir. Markmið þessa verkefnis var að búa til og þróa verkefni fyrir nemendur í framhaldsskóla með þetta í huga. Ákveðið var að verkefnin skyldu snúast um diffrun bæði vegna áhuga höfundar á því efni og að rannsóknir hafa sýnt að íslenskir framhaldsskólanemendur eiga í mestum erfiðleikum með diffrun og tegrun að loknum framhaldsskóla. Continue reading 'Sóley Benediktsdóttir'»

Nýdoktorsstaða

Benedikt Magnússon, júlí 6, 2021

Laust er til umsóknar starf nýdoktors við stærðfræðistofu Raunvísindastofnunar Háskólans. Nýdoktornum, sem starfið hlýtur, er ætlað að stunda rannsóknir á sviði stærðfræði, hreinnar eða hagnýtrar, eða stærðfræðilegrar eðlisfræði.

Sjá:
https://euraxess.ec.europa.eu/jobs/658209
https://www.stjornarradid.is/efst-a-baugi/laus-storf-a-starfatorgi/auglysing/?id=25274

Doktorsvörn — Aruna Rajagopal

Benedikt Magnússon, maí 20, 2021

Hvenær: 21. maí 2021 13:00 til 15:00
Hvar: Askja, stofa 132

Vörninni verður streymt

Doktorsefni: Aruna Rajagopal

Heiti ritgerðar: Vökvaaflfræði utan varmajafnvægis frá sjónarhóli samhverfu (Out of equilibrium hydrodynamics with and without boost symmetry)

Continue reading 'Doktorsvörn — Aruna Rajagopal'»

Gestur Ólafsson, Louisiana State University

Carlos Argaez Garcia, febrúar 11, 2021

Math colloquium

Fyrirlesari: Gestur Ólafsson, Louisiana State University

Titill: Atomic decomposition of Bergman spaces on Hermitian Symmetric Spaces

Staðsetning: Zoom link will be sent by email
Tími: Þriðjudag 16.febrúar kl. 16:00

Ágrip:

Hermitian symmetric spaces, bounded or unbounded, and spaces of functions or distributions on those spaces show up naturally in com- plex analysis, Lie theory, functional analysis and several other parts of mathematics. In this talk we will discuss some resent work on dis- cretization/atomic decomposition of Bergman spaces on those domains and their unbounded realization.

The story goes back to the work of Coifman and Rochberg in the 1980’s where they provided atomic decompositions for Bergman spaces on (the unbounded realization of) bounded symmetric domains as well as on the unit ball. Their atoms were build from the Bergman kernel. One of the shortcomings of their work was that their results did not readily transfer to the bounded realization of the domain except in the case of the unit ball.

By applying representation/coorbit theory we obtain a large family of new atoms, including those of Coifman and Rochberg, for Bergman spaces on bounded symmetric domains. Our approach also allows us to describe the relation between atoms for the bounded and unbounded realizations of the domain thus solving one of the issues raised by Coif- man and Rochberg. If time allows then we will list some open questions for domains of rank higher than one.

NORNDiP 2021 – Annual conference on January 29

Valentina Giangreco, janúar 24, 2021

This year, the Nordic Network for Diversity in Physics is holding its annual meeting as a one-day online event on 29th January, from 9.00 to 15.30.
Attendance is free of charge, but registration is mandatory to get access to the Zoom link and the recorded videos.

Highlights of the event:

Angela Saini’s talk. Angela Saini is a British journalist whose highly-regarded books and broadcasts on important issues around representation and discrimination in science and society have received widespread praise. She will speak on “Racism in science and society”. This is a topic that Angela researched extensively for her book Superior: The Return of Race Science.

Round-table: How to work against harassment – A discussion from a Nordic perspective. There will be reports on harassment reporting practices in academia from all the Nordic countries, and a round table discussion. Jóhanna Ella Jónsdóttir will be be the speaker for Iceland. Professor Helen Dannetun from Linköping University will moderate the discussion on „How to work against harassment – A discussion from a Nordic perspective“.

For more details about the conference, program, and the NORNDiP network visit: https://www.norndip.net
Registration at this link: https://indico.cern.ch/event/979804/registrations/66795/

Anders Karl Claesson, University of Iceland

Carlos Argaez Garcia, janúar 12, 2021

Math colloquium

Fyrirlesari: Anders Karl Claesson, Háskóli Íslands

Titill: On the problem of Hertzsprung and similar problems

Staðsetning: Via Zoom. Link to be sent.
Tími: Þriðjudag 19.janúar kl.10:00

Ágrip:

Drawing on a problem posed by Hertzsprung in 1887 (sometimes called the n-kings problem), we say that a permutation w contains the Hertzsprung pattern u if there is factor w(d+1)w(d+2)…w(d+k) of w such that w(d+1)-u(1) = … = w(d+k)-u(k).  Using a combination of the Goulden-Jackson cluster method (which we explain) and the transfer-matrix method we determine the joint distribution of occurrences of any set of (incomparable) Hertzsprung patterns, thus substantially generalizing earlier results by Jackson et al. on the distribution of ascending and descending runs in permutations.  We apply our results to the problem of counting permutations up to pattern-replacement equivalences, and using pattern-rewriting systems—a new formalism similar to the much studied string-rewriting systems—we solve a couple of open problems raised by Linton et al. in 2012.

Midway evaluation, Daniel Amankwah

Sigurður Örn Stefánsson, nóvember 30, 2020

Room: Via Zoom. Link to be sent.
Time: Friday, December 11, at 10:00.

Doctoral student: Daniel Amankwah

Project title: Scaling limits of random, face-weighted, tree like planar maps.

Project description: The doctoral project lies in the scope of random planar maps. We investigate scaling limits of various classes of discrete planar maps which are by construction “tree-like”. These include Halin maps, outerplanar maps, series-parallel maps and more. The Brownian Continuum Random tree (CRT), introduced by David Aldous has been known to be the limit of various different discrete models of planar maps uniformly sampled. We focus on the case when each face in the maps is assigned a heavy tailed weight so that a typical face is in the domain of attraction of a stable law. It is known that for several such models for treelike graphs the scaling limits are the so-called stable looptrees. We aim to understand how generically this happens. For this reason we will consider classes of maps which have not been studied in this scope in the literature. Examples include Halin maps, Series-Parallel maps and Maps of bounded tree-width.

Supervisor: Sigurður Örn Stefánsson

Elisa Domínguez-Hüttinger, Universidad Nacional Autónoma de México

Carlos Argaez Garcia, nóvember 7, 2020

Math colloquium

Fyrirlesari: Elisa Domínguez-Hüttinger, Universidad Nacional Autónoma de México

Titill: A “triple-switch” hybrid mathematical model of epidermal homeostasis.

Staðsetning: Via Zoom. Link to be sent.
Tími: Föstudag 13.nóvember kl.14:00

Ágrip:

The epidermis is the outermost layer of the skin. It is a stratified epithelium, constituted by layers of epithelial cells (keratinocytes) with increasing levels of differentiation. The basal layer is formed by undifferentiated cells with proliferative capacity, while the most external layer, termed skin barrier, is formed by terminally differentiated cells that are embedded in a lipid matrix. This skin barrier hinders the invasion of pathogens and other aggressors, protecting the organism from environmental disturbances. Transient environmental perturbations that increase the pathogen load or damage the skin barrier can trigger both immune and tissue remodelling responses, resulting in increased pathogen elimination but also affecting its infiltration rate. Under healthy conditions, this complex feedback control structure effectively counteracts environmental aggressors.  However, perturbations by genetic and environmental factors can lead to the loss of homeostasis and the onset and progression of complex epidermal tissue diseases including atopic dermatitis, psoriasis and skin carcinomas. Characterizing the responses of the epidermis to these perturbations is pivotal to uncover pathogenic mechanisms and improve strategies for diagnosis, prevention and treatment of these diseases.  However, this task is difficult to achieve from a purely experimental or clinical perspective, because these perturbations: (1) Often lead to synergic and non-linear responses that are hard to predict experimentally; (2) Can affect several regulatory processes that operate at different time scales; (3) May result in symptoms that are clinically subtle; and (4) Can affect disease progression  in a history-dependent manner. Here we propose a triple-switch mathematical model that couples a bistable motifs describing the activation of innate and adaptive immune responses as well as the differentiation of skin cells with the dynamically changing tissue level properties. We will show how mathematical analysis of this hybrid model has allowed us to: (1) Characterize the effects of genetic and environmental perturbations on epithelial homeostasis; (2) Identify risk factors that increase the vulnerability to environmental aggressors, and (3) Design new strategies for early detection and prevention of complex epidermal diseases.

Juan Fernando Angel Ramelli

Valentina Giangreco, nóvember 4, 2020

PhD defense, Friday November 6 at 14.00, in Veröld, room 023

Entanglement in Quantum Lifshitz Theories

The defense will be streamed

Live stream:https://www.youtube.com/user/HIvarp/live

Opponents: 
Dr. Stefan Vandoren, Professor at Utrecht University, The Netherlands.
Dr. Jens Hjörleifur Bárðarson, Associate Professor at KTH Royal Institute of Technology, Sweden

Advisor: Dr. Valentina Giangreco Puletti, Professor at the Faculty of Physical Sciences, University of Iceland 

Doctoral committee: 

Dr. Lárus Thorlacius, Professor at the Faculty of Physical Sciences, University of Iceland
Dr. Þórður Jónsson, Professor at the Faculty of Physical Sciences, University of Iceland
Dr. Erik Tonni, Associate Professor at SISSA, Italy.

Chair of Ceremony: Dr. Einar Örn Sveinbjörnsson, Professor and the Head of the Faculty of Physical Sciences, University of Iceland

Abstract:
In recent years, the study of entanglement properties of quantum field theories has led to deep insights in fields as diverse as quantum gravity and condensed matter physics. Originating as effective field theories for certain quantum dimer models, the Quantum Lifshitz Model (QLM) and its generalizations are bosonic quantum field theories with anisotropic scaling symmetry between space and time. Being closely related to conformal field theories, they provide a fruitful playground, where diverse entanglement calculations can be performed analytically.

In this thesis, we concentrate on two entanglement measures, the entanglement entropy and logarithmic negativity. Motivated to extract subleading universal behavior, we perform analytic calculations in two and higher even dimensions. In order to make the calculations tractable, we put the QLM on compact manifolds, such as spheres and tori, where the spectrum of a certain operator appearing in the ground state of the theory is explicitly known. Mostly by means of the replica method, we then find analytic expressions for the finite subleading terms of the entanglement entropy and logarithmic negativity of the ground state, as well as the entanglement entropy of the excited states of the QLM. In the case of the ground state entanglement entropy, we provide analytic expressions for the sub-leading terms as functions of the dimension and the dynamical critical exponent. For the excited states we provide analytic formulae of the sub-leading coefficients as functions of the excitation numbers.

Watse Sybesma, Háskóli Íslands

Carlos Argaez Garcia, október 27, 2020

Math Phys seminar

Fyrirlesari: Watse Sybesma, Háskóli Íslands

Titill: Myndun svarthola og risamassinn í miðju sólkerfisins.

Staðsetning: Via Zoom. Link to be sent.
Tími: Föstudag 30.október kl.12:00

Ágrip:

Nóbelsverðlaunin í eðlisfræði í ár snúast um svarthol, bæði út frá kenningum og rannsóknum. Breski eðlisfræðingurinn Roger Penrose setti fram kenningu sem tengir saman myndun svarthola og almennu afstæðiskenninguna og þýski stjarneðlisfræðingurinn 
Reinhard Genzel og bandaríski stjörnufræðingurinn Andrea Ghez hafa sýnt fram á að ósýnilegur og afar eðlisþungur hlutur stýrir hreyfingu stjarna í miðju sólkerfis okkar og risasvarthol er eina mögulega skýringin. Í fyrirlestrinum verður farið yfir þessar rannsóknir og þær kynntar. Athugið að fyrirlesturinn fer fram á ensku.