Supervisors: 

• Prof. Martin Plenio, University of Ulm/Imperial College London
• Dr. Alex Retzker, Hebrew University of Jerusalem

PhD Research Project: Phase Transitions in Ion Traps

During the PhD studies at the doctoral training centre in Controlled Quantum Dynamics, my research was focused on using ion traps for studying phase transitions.

Ion traps are devices that use a combination of electric and magnetic fields to trap ions in vacuum. Ions can then be cooled to temperatures close to absolute zero. At low temperatures ions form crystals and they can be directly seen using a microscope and a camera. The shape of the crystals can be precisely controlled by changing trap parameters. It is possible to obtain linear chains, zigzag chains, planes of ions and various three dimensional structures. 
A structural change of ion crystal from one configuration to another is a phase transition.  Thus ion traps are potentially great systems for studying the physics of phase transitions and processes associated with phase transitions, such as formation of topological defects. Moreover, ions can be cooled to such low temperatures that they have to be described using quantum mechanics. Therefore, ion crystals may be useful for quantum computation and quantum simulations.

DTC Publications and preprints

For full list of my publication refer to arXiv

• Universality in the dynamics of second-order phase transitions, G. Nikoghosyan, R. Nigmatullin, M.B. Plenio, arXiv:1311.1543
• Dynamics of topological defects in ion Coulomb crystals,  H. L. Partner, R. Nigmatullin, T. Burgermeister, K. Pyka, J. Keller, A. Retzker, M. B. Plenio, T. E. Mehlstäubler, New Journal of Physics, 15 103013 (2013)
• Causality and Defects as Relics of Symmetry Breaking in Ion Traps, K. Pyka, J. Keller, H. Partner, R. Nigmatullin, T. Burgermeister, D.M. Meier, K. Kuhlmann, A. Retzker, M.B. Plenio, W.H. Zurek, A. del Campo, T.E. Mehlstäubler, Nature Communications 4, 2291 (2013)
• Observation of the Kibble-Zurek scaling law for defect formation in ion crystals, S. Ulm, J. Roßnagel, G. Jacob, C. Degünther, S.T. Dawkins, U.G. Poshinger, R. Nigmatullin, A. Retzker, M. B. Plenio, F. Schmidt-Kaler, K. Singer, Nature Communications 4, 2290 (2013)
• Formation of helical ion chains, R. Nigmatullin, A. del Campo, G. De Chiara, G. Morigi, M. B. Plenio,  A. Retzker, arXiv:1112.1305

Talks

• Dynamics of topological defects in ion Coulomb crystals. Seminar, Institute of theoretical physics, University of Ulm, Germany, June 2013
• Investigating Kibble-Zurek mechanism in ion traps. Seminar, Quantum physics institute, University of Ulm, Germany, April 2013
• Testing Kibble-Zurek mechanism in ion traps. APS meeting, Baltimore, US, March 2013
• Experimental Tests of Kibble-Zurek Mechanism in Ion Traps. Seminar, Institute of theoretical physics, University of Ulm, Germany, February 2013
• Invited talk: Linear to zigzag phase transition in ion traps. Quantum Lunch Seminar, Los Alamos National Laboratory, US, July 2013
• Trapped ions as simulators of physical systems. Seminar, Ion Quantum Technology Group, University of Sussex, UK, April 2012
• Formation of helical ion chains. DPG meeting, Stuttgart, Germany, April 2012
• Invited talk: Solitons in zigzag ion chains. CoQuS retreat, Traunkirchen, Austria, October 2011
• Testing Kibble-Zurek mechanism using Penning traps. Seminar, Theoretical Quantum Physics Group, University of Saarland, Germany, February 2011 

Posters

Phase transitions in ion traps, Sep 2010