Professor **Alexander Balatsky** will be joining Nordita in September 2012.

His field of research is theoretical condensed matter physics where he has made a number of seminal contributions. His recent work has mainly been in strongly correlated materials, unconventional superconductivity, and biomolecular electronics.

Professor Balatsky received his PhD in 1987 at the Landau Institute for Theoretical Physics and Moscow Physical Technical Institute in Moscow. He comes to Nordita from Los Alamos National Laboratory and has previously held positions at the Landau Institute and the University of Illinois at Urbana Champaign.

**John S. Wettlaufer**, the A.M. Bateman Professor at Yale University,
and currently a Wenner Gren visiting professor at Nordita (see the
Nordita News 2011, Issue 2), was awarded the
**Tage Erlander Guest Professorship 2012**.
A condensed matter theorist, John's expertise lies in, among other things, surface and size effects in melting and freezing, pattern formation and stability of moving boundaries, applied mathematics and fluid dynamics, and the statistical physics of soft matter. His work has implications in astrophysics, biophysics and geophysics.

The holder of the chair is appointed by invitation from the Swedish Research Council. Since its inception, this prestigious award has been given to accomplished scientists covering a broad range of topics including mathematics, signal processing, applied physics, theoretical biology, nuclear physics, and chemistry. Nobel Laureates, Fields Medalists and members of many National Academies of Science are included in the list of past Erlander Professors.

John's term will be spent at Nordita where with collaborators and students he plans to study the surface phase transitions underlying planetary accretion, the statistical physics of rapid climate change, and lattice Boltzmann methods for electromagnetism and fluid dynamics.

Three new postdoctoral fellows arrived at Nordita in October.

Nordita Fellow
**Dr. Dmitri Bykov** received his PhD from Trinity College Dublin in 2011.
His research interests include spin chains, sigma models, gauge theory and
string theory.

Post-doctoral fellow **Dr. Ville Keränen** received his PhD from the University of Helsinki in 2011. He is working on the use of the AdS/CFT duality to address questions in quantum field theory. His fellowship at Nordita is supported by a grant from the Icelandic Research Fund.

Nordita Fellow
**Dr. Dmytro Volin** received his PhD from Univesité Paris-Sud XI, Orsay in 2009 and was a postdoc at the Pennsylvania State University before joining Nordita. His research interests include strongly coupled gauge theories and exactly solvable models, with particular focus on integrability in the AdS/CFT correspondence.

Nordita PhD student **Tobias Zingg** successfully defended his PhD thesis "Holographic Models for Condensed Matter" at the University of Iceland on September 2. His PhD advisor is Nordita Director Larus Thorlacius.

Tobias will be staying on at Nordita as a post-doctoral fellow, supported by a grant from the Icelandic Research Fund, until summer 2012.

Nordita is happy to host **Christos Tsagas** for over 2 months.
Christos has been an Assistant Professor at the University of
Thessaloniki in Greece since the autumn of 2005. Previously, he has been a
postdoctoral researcher at Portsmouth (ICG), Cape Town (RCG) and Cambridge
(DAMTP). He received his PhD from the University of Sussex in 1998, where
he worked under the supervision of Professor John Barrow.

Christos is a theorist with research interests in the interface between Relativistic Cosmology and Relativistic Astrophysics and he is the author/coauthor of approximately fifty scientific articles, reviews and conference proceedings. His main expertise is in the area of cosmological magnetic fields and the large-scale structure of the universe. His work on the interaction between electromagnetism and spacetime geometry has attracted the attention of the wider scientific community, with related news pieces appearing in magazines and newspapers worldwide.

During
his visit between mid September and early December 2011,
Christos will be working with Axel Brandenburg and his research
group on a project studying the interaction between gravitational waves
and electromagnetic fields.

Members of the **ERC-supported AstroDyn project** were excited to report on
what they call a *negative effective magnetic pressure instability*
(or NEMPI for short). During the last year they did already verify that
on large enough length scales covering many turbulent eddies, a modestly
strong magnetic field can suppress turbulence, lowering therefore the
turbulence pressure locally. In spite of the added magnetic pressure, the
total effective pressure can still get reduced.

Last September, during the most recent visit of
**Nathan Kleeorin**
and **Igor Rogachevskii**,
they detected for the first time in a turbulence simulation
that this effect can lead to an instability and, as a result,
can form large-scale magnetic flux concentrations.
This paper is now published in the
**Astrophysical Journal Letters 740, L50 (2011)**
According to the authors, **this marks an important milestone in their
quest to understand the formation of active regions and ultimately sunspots**.
They have assembled some additional material including some movies on
a **web page**.
The picture above shows how a magnetized structure (yellow) with negative effective magnetic pressure must attain higher gas pressure to have lateral pressure equilibrium.
This higher pressure leads to higher density, which makes the structure heavier, so it sinks,
as is also seen in the sequence of pictures above.

All Nordita positions are announced through the job application manager,
**jam.nordita.org**, where one also finds electronic application forms.

**Nordita Post-Doctoral Fellowships**

- Application deadline: 15 November 2011
- For details see http://www.nordita.org/docs/nordita_fellows_2012.pdf

**Nordita Assistant Professor in Theoretical Condensed-Matter Physics**

- Application deadline: 22 November 2011
- For details see http://www.nordita.org/docs/nordita_astprofessor_2012.pdf

Nordita invites **applications for a new round of Nordita Programs** in 2013-2014. The announcement and the guidelines for submitting a proposal can be found at **www.nordita.org/propose**.
The deadline is the **15th of December**.

A Nordita Scientific program is an extended workshop where a limited number of scientists work together on specific topics for a period of 4 to 6 weeks. **Program topics can range beyond the traditional borders of theoretical physics and scientists in related areas of the natural sciences are encouraged to submit proposals.**

Up to 25 participants can be accommodated at any given time. This typically includes a core of 8-12 internationally recognized leaders in the subject area of the program, 5-8 invited Nordic scientists, and a limited number of other applicants including accompanying postdoctoral fellows and PhD students.

- November 1 to November 30 2011

- The 4-week program will be devoted to geometrical subjects motivated by string theory, and to recent developments in string theory and related physical fields (including quantum field theory) which are of strong geometrical interest. While the program will cover all areas of interaction between string theory and geometry, to provide additional focus we will emphasize particular subareas such as: the application of supersymmetry in differential geometry, generalized geometry, vertex algebras, and topological field theories.

- January 23 to February 17, 2012

- There has been remarkable progress in understanding non-perturbative dynamics of gauge fields and their relationship to string theory in recent years. Many important developments have been made by using methods of exactly solvable systems. The topics will include (i) exact results in the AdS/CFT correspondence (ii) scattering amplitudes (iii) supersymmetric gauge theories (iv) Bethe ansatz and exact solvability in quantum field theory

- Coordinators: Lisa Freyhult, Vladimir Kazakov, Charlotte Kristjansen, Joseph Minahan, Konstantin Zarembo

- 27 February ? 23 March 2012

- This program focuses on the different methods for modeling the dynamics of biomolecular systems, ranging from force-field based all-atom representation of individual biomolecules to coarse-grained models for multi-component systems. In particular, the link between these 'complementary' modelling approaches, which cover distinct length and time scales, is of central interest.

- Coordinators: Hans Behringer, Stefan Wallin, Ralf Eichhorn

- January 9-20, 2012

- The
**Nordita School in Theoretical Particle Physics**will take place at Nordita in the period**January 9-20, 2012**and is organized by**Paolo Di Vecchia**,**Troels Harmark**,**Lárus Thorlacius**, and**Konstantin Zarembo**. It is the third annual winter school organized at Nordita in Stockholm. The school is mainly intended for PhD students and young postdocs from the Nordic countries. The topics at the school include lectures on the*standard model of particle physics, beyond the standard model physics, non-perturbative aspects of quantum field theory, black holes, string theory, holography and AdS/CFT, applications of AdS/CFT, and the experimental search for quantum gravity*. Lecturers will include P. Di Vecchia (Nordita), G. Ferretti (Chalmers, Göteborg), S. Hannestad (University of Aarhus), T. Harmark (Nordita), S. Hossenfelder (Nordita), N. A. Obers (Niels Bohr Institute), A. Raklev (Oslo), F. Sannino (CP3 origins, SDU, Odense), L. Thorlacius (Nordita), P. Vieira (Perimeter Institute, Canada) and K. Zarembo (Nordita)

The **final report**
from the Nordita program on
**Dynamo, Dynamical Systems and Topology (25 July - 19 August 2011)**
lists among its main achievements the establishment of links between
the dynamo theory, numerical simulations and observational results,
developing collaborations, approaches and ideas, and getting new science
results. The Nordita program **stimulated further development of the dynamo
theory, numerical simulations and observational programs**.

The total number of program participants was 45 including 4 women, and
20 Nordic participant (Denmark 1, Finland 3, Sweden 16, of which 12 from
Stockholm). A significant portion of the participants came from the US
(5), Russia (4), Brazil (2), as well as Germany (6), Israel (2), and
the UK (2). Of the 33 people from outside Stockholm, 24 stayed for 3
weeks or longer. The program marked a highlight in **the ERC-supported
Astrophysical Dynamo Project at Nordita**, with two of the post-docs
(Piyali Chatterjee and Gustavo Guerrero) just departing.

The next Nordita Board meeting will take place in Stockholm on **10 February 2012**.

→ Link to electronic preprints: **www.nordita.org/preprints**

The following preprints have been posted to the Nordita on-line archive since the last newsletter issue:

- 2011-070
- "Is the solar spectrum latitude dependent? An investigation with SST/TRIPPEL"
- D. Kiselman, T. Pereira, B. Gustafsson, M. Asplund, J. Melendez, K. Langhans
*Astron. Astrophys. (submitted)*

- 2011-071
- "Mean-field theory in magneto-hydrodynamics and the generation of magnetic flux concentrations"
- Koen Kemel
*Licentiate Thesis*

- 2011-072
- "Detection of negative effective magnetic pressure instability in simulations"
- A. Brandenburg, K. Kemel, N. Kleeorin, D. Mitra, I. Rogachevskii
*Astrophys. J. Lett. 740, L50 (2011)*

- 2011-073
- "Holographic Schwinger Effect"
- G. Semenoff and K. Zarembo
*Phys. Rev. Lett. 107 (2011) 171601*

- 2011-074
- "Spin diffusion in clouds of strongly interacting cold atoms"
- G. M. Bruun and C. J. Pethick

- 2011-075
- "An Extreme Pulsar Tail Protruding from the Frying Pan Supernova Remnant"
- Ng, C. -Y.; Bucciantini, N.; Gaensler, B. M.; Camilo, F.; Chatterjee, S.; Bouchard, A.
*submitted to the Astrophysical Journal*

- 2011-076
- "Numerical simulation of forced convection over a periodic series of rectangular cavities at low Prandtl number"
- E. Stalio, D. Angeli, G.S. Barozzi
*Int. J. Heat Fluid Flow, 32, 1014-1023 (2011)*

- 2011-077
- "Effects of stratification in spherical shell convection"
- P. J. Käpylä, M. J. Mantere, A. Brandenburg
*Astron. Nachr. (submitted)*

- 2011-078
- "Verification of Reynolds stress parameterizations from simulations"
- J. E. Snellman, A. Brandenburg, P. J. Käpylä, M. J. Mantere,
*Astron. Nachr. (submitted)*

- 2011-079
- "Dependence of the large-scale vortex instability on latitude, stratification and domain size"
- Maarit J. Mantere, Petri J. Käpylä, Thomas Hackman
*submitted to Astronomische Nachrichten*

- 2011-080
- "A Low Order Theory of Arctic Sea Ice Stability"
- W. Moon, J.S. Wettlaufer

- 2011-081
- "Decadal to seasonal variability of Arctic sea ice albedo"
- S. Agarwal, W. Moon, J.S. Wettlaufer

- 2011-082
- "Crustal failure during binary inspiral"
- A. J. Penner, N. Andersson, D. I. Jones, L. Samuelsson and I. Hawke

- 2011-083
- "Role of correlations in population coding"
- Peter E Latham and Yasser Roudi
*To appear in "Principles of Neural Coding", edited by Stefano Panzeri and Rodrigo Quian Quiroga*

- 2011-084
- "Integrability in anyonic quantum spin chains via a composite height model"
- Paata Kakashvili, Eddy Ardonne

- 2011-085
- "Dynamics of saturated energy condensation in two-dimensional turbulence"
- Chi-kwan Chan, Dhrubaditya Mitra, Axel Brandenburg
*Phys. Rev. E (submitted)*

- 2011-086
- "Interaction of gravitational waves with matter"
- A. Cetoli and C. J. Pethick

- 2011-087
- "Modeling spatio-temporal nonlocality in mean-field dynamos"
- M. Rheinhardt, A. Brandenburg
*Astron. Nachr. (submitted)*

- 2011-088
- "The fluctuating ?-effect and Waldmeier relations in the nonlinear dynamo models"
- V.V. Pipin, D.D. Sokoloff
*Phys. Scr. (submitted)*

- 2011-089
- "Friedel Oscillations in Holographic Metals"
- V. Giangreco M. Puletti, S. Nowling, L. Thorlacius, and T. Zingg

- 2011-091
- "The Young Modulus of Black Strings and the Fine Structure of Blackfolds"
- J. Armas, J. Camps, T. Harmark, N. A. Obers

- 2011-092
- "Current helicity of active regions as a tracer of large-scale solar magnetic helicity"
- H. Zhang, D. Moss, N. Kleeorin, K. Kuzanyan, I. Rogachevskii, D. Sokoloff, Y. Gao, H. Xu

If you have information about meetings or other items that would be useful to include in Nordita News, please send it to Anne Jifält, Nordita, email: anne /+/ kth.se.

For back issues of the Nordita newsletter, see http://www.nordita.org/news/about/archive/issues/index.php