Permanent Members:

Eva Lindroth	Svante Jonsell
Professor	Assoc. Professor
Room: C4:1001	Room: C4:3011
+46-8-5537-8616	+46-8-5537-8625
E-mail-Name:	E-mail-Name:
Eva.Lindroth	Svante.Jonsell

Postdocs and PhD students




Marcus Dahlström	Tor Kjellsson	Muhammad Umair	Carl Wesslén
Postdoc	PhD student	PhD student	PhD student
Room: C4:3009	Room: C4:3007	Room: C4:3013	Room: C4:3009
+46-8-5537-8630	+46-8-5537-8623	+46-8-5537-8432	+46-8-5537-8630
E-mail-Name:	E-mail-Name:	E-mail-Name:	E-mail-Name:
Marcus.Dahlstrom	Tor.Kjellsson	Muhammad.Umair	Carl.Wesslen


To send an email: 'E-Mail-Name'@fysik.su.se





Former members:

Dr. Thomas Carette	Now at ING Belgium	tcarette@gmail.com
Dr. Jakob Bengtsson	Now at Lund University	jakob.bengtsson@matfys.lth.se
Dr. Paul Halkyard	Now at The International English School
Dr. Luca Argenti	Now at Universidad Autonoma de Madrid, Spain	luca.argenti@gmail.com
Dr. Michael Genkin	Now at the Max-Planck-Institute for the Physics of Complex Systems, Dresden, Germany	genkin@pks.mpg.de
Dr. Erik Waltersson	Now at Europaskolan in Strängnäs	Erik.Waltersson@student.europaskolan.se
Dr. Fabrizio Ferro	Now at Areva Erlangen, Germany	fabrizioferro79@googlemail.com
Dr. Sølve Selstø	Now at Oslo University College, Norway	solve.selsto@gmail.com
Dr. Dragan Nicolic	Now at California Institute of Technology, Jet Propulsion Laboratory, Ca, USA	dnikolic@ualberta.ca
Dr. Mohamed Ourdane	Now at CISCO SYSTEMS in Luxembourg	mourdane@cisco.com
Dr. Andre Bürgers	Now at Nacka Gymnasium	bilbobaggins@spray.se
Dr. Maria Tokman	Now back in St. Petersburg	tokman@mail.ru
Dr. Nicklas Brandefelt	Now at Royal Institute of Technology (KTH), Stockholm	Nicklas.Brandefelt@sth.kth.se
Dr. Josef Anton	Now at Ulm University, Germany	josef.anton@uni-ulm.de
Dr. Jose Luis Sanz-Vicario	Now at Universidad de Antioquiq, Medellin, Coulombia	sanjose@pegasus.udea.edu.co


 
 

Research Areas

 Electron-ion recombination

The electron-ion recombination processes are essential for a fundamental understanding of interactions in atoms and ions and have also astrophysical relevance. Experimental studies in storage rings where cold ions and electrons collide with a well defined relative energy allow us to follow the recombination process in detail. The studies are performed for ions of almost any degree of ionization. We work in close connection with experiments, performed for example at the S-EBIT (Stockholm Electron Beam Ion Trap) or at storage rings like CRYRING in Stockholm, TSR in Heidelberg, and also at GSI in Darmstadt. Since it is necessary to describe doubly excited states in medium or highly charged ions where a relativistic treatment is essential we have developed a scheme based on relativistic many-body perturbation theory combined with the method of complex rotation.

A few recent related publications:  PRL 100,  JPB 40,  A and A 459,  PRL 95

 Time-dependent problems in atomic systems, interaction of atoms with laser pulses

With the constant intensity increase and duration decrease of experimentally available laser pulses, more and more advanced theoretical models are necessary to describe their interaction with atoms. In particular, it is sometimes necessary to go beyond the dipole approximation and work with the Dirac equation rather then with the Schrödinger equation. We apply different methods, like complex scaling or Magnus propagator for explicitly time-dependent Hamiltonians and Floquet theory, to analyze ionization spectra, ionization probabilities and population of states in atoms exposed to electromagnetic fields.

A few recent related publications:  PRA 79,  PRA 78,  PRL 105,  PRA 85

 Quantum dots, dot molecules and rings

Since the beginning of the 1990's a new field has developed on the border between solid state, condensed matter and atomic physics. The possibility to confine a small and controllable number of electrons in tunable electrostatic potentials inside semiconductor materials has been vastly explored in this new field nowadays known as quantum dots and quantum rings physics. The interest for quantum dots and rings is mainly motivated by the fact that they can be used as building blocks for the construction of nanoelectronic devices, in the future possibly even as q-bits i.e. the essential part of quantum computers. We perform structural many-body perturbation theory calculations on quantum dots and also work with possible applications in quantum information processing.

A few recent related publications:  PRB 81 (1),  PRB 81 (2),  PRB 79 (1),  PRB 79 (2),  PRB 76 (1),  PRB 76 (2)

 Decoherence and open quantum systems

Open quantum systems have become more and more important during the last decades, covering a wide spectrum of applications in surface, atomic, nuclear and particle physics. In particular, they present a crucial framework in quantum information theory which makes it possible to study fundamental aspects like dephasing and entanglement dynamics and environmentally induced loss of quantum coherence ususally called decoherence. The resulting non-unitary time evolution is often described by so called master equations for the density matrix. We use one of the most common, the Lindblad master equation, to study open atomic systems and devices that are potential candidates for a quantum computer basis, like quantum dots or ion traps.

A few recent related publications:  PRA 80,  JPA 42 (1),  PRB 79 (1),  JPA 42 (2),  JPA 41

 Multiply excited states in atoms and ions

Doubly excited states are very sensitive to correlation and the usual independent particle models can often not even give a qualitative description of them. These states thus provide good test cases for studies of correlation. For such studies few-body systems with two or three electrons are especially interesting since they are within reach for a complete ab initio treatment. Doubly excited states, which in general are autoionizing, are also important as intermediate states in many physical processes. Their description is essential to describe ionization of many-electron systems by photons or other particles, to understand the decay of states with inner shell vacancies or to describe electron-ion recombination for non-bare ions.

A few recent related publications:  EPJD 51,  JPB 40,  JPB 37

 Negative ions and photodetachment

In negative ions the last electron is, in general, bound only due to the dipole part of the electron-electron interaction, which is attractive. Many negative ions have just one bound state but often also long-lived resonant states exist which can be observed in photodetachment studies. We have worked with H^-, Li^- and He^- which has been treated from first principles as a full three-body system.

A few recent related publications:  PRA 78,  PRA 68

 Highly charged ions and inner shell vacancies in heavy elements

Inner shell vacancies in heavy elements are in general unstable and decay by electron or photon emission. Accurate X-ray spectroscopy of the emitted photon when the system make a transition between the the K, L and M shells gives information about relativistic and radiative effects. During a long time collaboration with the group of Paul Indelicato in Paris we have combined different numerical approaches and calculated a large number of transition energies for elements with nuclear charges ranging from Z=10 -100.

A few recent related publications:  PRA 73,  Rev. Mod. Phys. 75



  Further research topics (Antihydrogen, Brownian motors and Few-body physics) can be found on Svante Jonsell's homepage


 
 

Thesis from our group:

PhD Thesis September 2001: N. Brandefelt, Resonant States in Negative Ions

Licenciate Thesis June 2003: D. Nikolic, Dielectronic Recombination of lithiumlike ions

Master Thesis October 2003: E. Waltersson, A numerical survey of artifical atoms - Quantum Dots in two dimensions

PhD Thesis June 2004: D. Nikolic, Autoionizing states and their relevance in electron-ion recombination

Licenciate Thesis June 2007: E. Waltersson, Performance of Many-Body Perturbation Theory calculations on 2D Quantum Dots

Licenciate Thesis December 2008: M. Genkin, Feasibility study of resonant antiproton capture by ions and an open system approach to resonance decay

Licenciate Thesis June 2009: J. Bengtsson, Analysis of time-dependent systems decribed with a complex-scaled Hamiltonian

PhD Thesis May 2010: M. Genkin, Resonances, dissipation and decoherence in exotic and artificial atoms

PhD Thesis June 2010: E. Waltersson, On the role of the electron-electron interaction in two-dimensional quantum dots and rings

PhD Thesis April 2012: J. Bengtsson, On the use of the uniform complex scaling-method for studying time-dependent systems



"Examensarbeten" in Atomic Theory:

We can offer a variety of "Examensarbeten" within all the areas listed above. You will of course always work in close collaboration with us and get "hands on" help to understand and use the numerical tools we are using. Whether you consider writing your "Examensarbete" or just want more information or to discuss things - don't hesitate to contact us!
 
 

Recent Publications can be found at:

Eva Lindroth's homepage
Svante Jonsell's homepage
Marcus Dahlström's homepage
 
 

Address

Department of Physics
Stockholm University
Alba Nova University Center
S-106 91 Stockholm
SWEDEN
Fax: (+46)-8-5537 86 01
How to find us:
 

If you have questions or suggestions about this page please send an e-mail to
lindroth@fysik.su.se















Last updated Apr 10, 2012