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Recent News


2 August 2021: Paper in PR Research

Our paper is published where we measure effects of the quadrupole polarizability of a single atom in a quadrupole electric field: Gerard Higgins, Chi Zhang, et al., Observation of second- and higher-order electric quadrupole interactions with an atomic ion, Phys. Rev. Research 3, L032032 (2021).

 
July 2021: Manuscript on micromotion minimization

We have submitted our manuscript Gerard Higgins, et al., Micromotion minimization using Ramsey interferometry, arXiv:2107.01902.
In this work we introduce and demonstrate new techniques which allow us to minimize unwanted electric fields at the ions’ position fast and precisely via interferometric pulse sequences.

 


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11 June 2021: Paper published in PRL

Our recent manuscript Filippo M. Gambetta, et al., "Exploring the Many-Body Dynamics Near a Conical Intersection with Trapped Rydberg Ions" has been published in Physical Review Letters (Phys. Rev. Lett. 126, 233404 (2021)).


20 January 2021 - Magnetic field shielding installed

Today we have installed a magnetic field shielding around our Rydberg ion experiment in order to increase the coherence times of our ion qubits.


21 October 2020 - PhD defense by Fabian Pokorny

Fabian today has defended his PhD thesis. Congratulations Dr. Fabian!


22 September 2020: Paper published in PRL

Our paper Filippo M. Gambetta, et al., "Long-range multibody interactions and three-body antiblockade in a trapped Rydberg ion chain" has been published in PRL (Phys. Rev. Lett. 125, 133602 (2020)).


21 September 2020 - PhD defense by Chi Zhang

Chi today has defended his PhD thesis. Congratulations Dr. Chi!


September 2020: Welcome Marion Mallweger!

Marion has joined the group as a PhD student. Welcome Marion!


May 2020: Manuscript on magic trapping

We have submitted our manuscript Fabian Pokorny, Chi Zhang, Gerard Higgins and Markus Hennrich, Magic trapping of a Rydberg ion with a diminished static polarizability, arXiv:2005.12422. In this work we report the realization of a microwave-dressed Rydberg states with vanishing polarizability. In this way, we make the Rydberg ion insensitive to low-frequency electric fields. This allows us to achieve magic trapping of a Rydberg system for the first time. We demonstrate Rabi oscillations between a low-lying electronic state and the magically trapped Rydberg state.


May 2020: Manuscript on quadrupole polarizability

We have submitted our manuscript Gerard Higgins, Chi Zhang, Fabian Pokorny, Harry Parke, Erik Jansson, Shalina Salim, and Markus Hennrich, Observation of effects due to an atom's electric quadrupole polarizability, arXiv:2005.01957. In this work we report the direct observation of effects due to a fundamental atomic property for the first time, namely, the electric quadrupole polarizability. To observe these effects we probe a highly-excited Rydberg ion confined in the strong electric quadrupole fields of a Paul trap.


29 April 2020 - Master thesis defense by Erik Jansson

Erik Jansson has defended his Master thesis via Zoom. Congratulations Erik!


15 April 2020 - Paper published in Nature

Today, our paper Chi Zhang, et al., "Sub-microsecond entangling gate between trapped ions via Rydberg interaction" has been published in Nature (Nature 580, 345 (2020)). Read more.


25 February 2020 - Paper published in PRL

Our paper Fabian Pokorny, et al., "Tracking the dynamics of an ideal quantum measurement" has been published in Physical Review Letters (Phys. Rev. Lett. 124, 080401 (2020)). Read more.


31 January 2020 - Master thesis defense by Anders Lindberg

Anders Lindberg has defended his Master thesis. Congratulations Anders!


October 2019: Paper on Highly Polarizable Rydberg Ion published in PRL

Our recent paper Gerard Higgins, et al., "Highly Polarizable Rydberg Ion in a Paul Trap" has been published in Physical Review Letters (Phys. Rev. Lett. 123, 153602 (2019)).


August 2019: Fast entanglement gate realised

Today, we have submitted our manuscript Chi Zhang, et al., "Sub-microsecond entangling gate between trapped ions via Rydberg interaction" to arXiv (arXiv:1908.11284). In this work we demonstrate a very fast entanglement gate in a trapped ion quantum computer by using Rydberg interaction. This work shows a viable route to increase the computational speed of a trapped ion quantum computer by two to three orders of magnitude.


April 2019: Paper on arXiv

Today we have submitted our manuscript Gerard Higgins, et al., "Highly-polarizable ion in a Paul trap" to arXiv:1904.08099. In this work we investigate a trapped ion with a gigantic polarizability. Ions are routinely trapped through the action of electric fields on the ion charge, with a tiny adjustment due to the ion polarizability. In this manuscript we study a highly-excited Rydberg ion, with a polarizability 100,000,000 times larger than a normal ion. We observe striking, new phenomena, such as strong coupling between the ion’s outer electron and the center-of-mass motion of the ion as a whole. This strong coupling lies at the heart of proposals to generate quantum entanglement fast, to drive phase transitions quantum-mechanically, and to carry out quantum simulations. Only now has this strong coupling been directly observed and thoroughly investigated. Moreover, this work sheds light on a miniscule correction that is applied to most precise atomic clocks. This correction results from the ion polarizability and the ion’s thermal motion. It’s thanks to the giant polarizability of Rydberg ions that we have been able to scrutinize this correction.


2 April 2019: Fabian Pokorny has defended his licentiate thesis!

Fabian today has defended his licentiate thesis at Stockholm University. Congratulations Fabian!


March 2019: Paper on arXiv

Today we have submitted our manuscript Fabian Pokorny, et al., "Tracking the dynamics of an ideal quantum measurement" to arXiv:1903.10398. In this work we observe the dynamics of a natural quantum measurement in a qutrit system.


December 2018: Welcome Erik Jansson!

 

Erik has joined the group as a Master student. Welcome Erik!

 

6 July 2018: Gerard Higgins has defended his PhD thesis - part 2!

Gerard today has defended the second part of his PhD thesis at University of Innsbruck. Congratulations Dr. Gerard!


July 2018: Welcome Shalina Salim!

 

Shalina has joined the group as a PhD student. Welcome Shalina!

 

July 2018: Welcome Harry Parke!

 

Harry has joined the group as a PhD student. Welcome Harry!

 

May 2018: Welcome Anders Lindberg!

 

Anders has joined the group as a Master student. Welcome Anders!

 

May 2018: Andreas Pöschl has defended his Master thesis!

 

Andreas today has defended his Master thesis. Congratulations Andreas!


27 April 2018: Gerard Higgins has defended his PhD thesis - part 1!

Gerard today has defended his PhD thesis at Stockholm University. This was the first part of his defence as he still needs to defend in Innsbruck in July. Congratulations Gerard!


November 2017: Paper published in Physical Review Letters

Today our manuscript G. Higgins, et al., "Coherent Control of a Single Trapped Rydberg Ion" was published in Physical Review Letters. The paper was highlighted as an Editors' selection.


August 2017: Paper on arXiv

Today we have submitted our manuscript Gerard Higgins, et al., "Coherent control of a single trapped Rydberg ion" to arXiv:1708.06387. In this work we carry out the first coherent Rydberg excitation of an ion and perform a single-qubit Rydberg gate, thus demonstrating basic elements of a trapped Rydberg ion quantum computer.


June 2017: Paper published in Physical Review X

Today our manuscript Gerard Higgins, Weibin Li, et al., "Single strontium Rydberg ion confined in a Paul trap" was published in Physical Review X. The paper was featured in physics.aps.org. for more details read the Fysikum's blog.


March 2017: Welcome Andreas Pöschl!

 

Andreas has joined the group as a Master student. Welcome Andreas!

 

November 2016: Paper on arXiv

Today we have submitted our manuscript Gerard Higgins, Weibin Li, et al., "A single strontium Rydberg ion confined in a Paul trap" to arXiv:1611.02184. In this work we investigate the basic physical properties of a trapped Rydberg ion in the electric field of a Paul trap. We believe that this investigation will be essential for future applications of trapped Rydberg ions in quantum information processing.


July 2016: Welcome Chi Zhang!

 

Chi has joined the group as a PhD student. He has done his Master at Ludwig-Maximilians-Universität München and his Master thesis in Michael Köhl's group (University of Bonn). Welcome Chi!

 

20 December 2015: First trapped Rydberg ions at Stockholm University

Today Gerard has for the first time after our move to Stockholm excited a trapped strontium ion into the Rydberg state. What is most impressive, this is less than 4 months after we started working on the experiment here in Stockholm. Congratulations! Excellent work of the whole team!


October 2015: First trapped ions at Stockholm University

 

Today we have observed our first trapped strontium ions at Stockholm University. Less than 2 months after starting to work in the lab here at Stockholm University the experiment is running again. Great job!

 

October 2015: Welcome Quentin Bodart!

 

Quentin has joined the group as a postdoctoral researcher. He has done his PhD on Atomic Gravimetry at the Université Pierre et Marie Curie, Paris 6 (Observatoire de Paris – SYRTE and Laboratoire National de Métrologie et d'Essais). Afterwards he worked as postdoctoral researcher at the European Space Agency and the University of Florence on Space Atom Interferometers. Welcome Quentin!

 

August 2015: Move to Stockholm University

We successfully moved the ion trap experiment from University of Innsbruck to Stockholm University. See below some pictures from the move.

move1
The packed ion trap in Innsbruck.
 
move2
Loading the ion trap into the truck.
 
move3
Unloading the equipment at Albanova.
 
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Fabian, ion trap and lasers in the new lab at SU.