Excellent news: Our project Open 2D Quantum Simulator (Open-2QS) is funded by a European Research Council (ERC) Synergy Grant - see here. We will be working alongside the groups of Igor Lesanovsky from the University of Tübingen and Ferdinand Schmidt-Kaler from the Johannes Gutenberg University Mainz on this exciting journey. Our project Open-2QS aims to use quantum simulators with electronically excited ion crystals to explore complex questions in physics, while also shedding light on intricate processes in chemistry, biology, and information processing. It’s an ambitious endeavor, and we’re grateful for the support of the ERC.
We have submitted our manuscript Harry Parke, et al., Phononic bright and dark states: Investigating multi-mode light-matter interactions with a single trapped ion arXiv:2403.07154.
We have submitted our manuscript Marion Mallweger, Milena Guevara-Bertsch, et al., Motional state analysis of a trapped ion by ultra-narrowband composite pulses, arXiv:2402.10041 .
We say goodbye to our wonderful interns Valeria (bottom left), Thomas (middle left) and Jan (top left)!
They all helped us with designing and testing a free-space UV laser bridge. The bridge is intended to deliver UV Gaussian beams between neighbouring labs using a commercial beam stabilisation system.
Our paper on Single-shot measurements of phonon number states using the Autler-Townes effect has been published in PRL. We are happy that it has been selected as an editor suggestion!
Marion Mallweger, et al.,Single-Shot Measurements of Phonon Number States Using the Autler-Townes Effect, Phys. Rev. Lett. 131, 223603 (2023).
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.
Our pre-print on Single-shot measurements of phonon number states using the Autler-Townes effect has been uploaded on Arxivs: Marion Mallweger, et al., Single-shot measurements of phonon number states using the Autler-Townes effect, New J. Phys. 23, 123028 (2021), 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.
We welcome Ivo Straka in our group. He will be joining us as a Postdoc.
Our paper on Micromotion minimization using Ramsey interferometry has been published in New Journal of Physics: Gerard Higgins, et al., Micromotion minimization using Ramsey interferometry, New J. Phys. 23, 123028 (2021), 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.
European Conference on Trapped Ions (hybrid ECTI 2021) hybrid conference was held as an online event with satellite meetings in Oxford (22 Nov) and Mainz (25 Nov). The conference brings together the European and international ion trapping communities and will cover topics in quantum computing and quantum simulations, quantum networks, precision measurements and optical clocks, molecular ions and atom-ion mixtures, non-neutral plasmas, novel approaches, and more.
We have submitted our manuscript José A. S. Lourenço, Gerard Higgins, Chi Zhang, Markus Hennrich, Tommaso Macrì, Non-Hermitian dynamics and PT-symmetry breaking in interacting mesoscopic Rydberg platforms, arXiv:2111.04378. In this work we simulate the dissipative dynamics of a mesoscopic system of long-range interacting particles which can be mapped into non-Hermitian spin models with a PT symmetry. We find rich PT-phase diagrams with PT-symmetric and PT-broken phases. Systems of Rydberg atoms and systems of Rydberg ions with strong dipolar interactions are particularly well suited for such studies.
Natalia has joined the group as a PhD student. Welcome Natalia!
Robin has joined the group as a PhD student. Welcome Robin!
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).
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.
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)).
Today we have installed a magnetic field shielding around our Rydberg ion experiment in order to increase the coherence times of our ion qubits.
Fabian today has defended his PhD thesis. Congratulations Dr. Fabian!
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)).
Chi today has defended his PhD thesis. Congratulations Dr. Chi!
Marion has joined the group as a PhD student. Welcome Marion!
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.
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.
Erik Jansson has defended his Master thesis via Zoom. Congratulations Erik!
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.
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.
Anders Lindberg has defended his Master thesis. Congratulations Anders!
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)).
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.
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.
Fabian today has defended his licentiate thesis at Stockholm University. Congratulations Fabian!
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.
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Erik has joined the group as a Master student. Welcome Erik! |
Gerard today has defended the second part of his PhD thesis at University of Innsbruck. Congratulations Dr. Gerard!
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Shalina has joined the group as a PhD student. Welcome Shalina! |
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Harry has joined the group as a PhD student. Welcome Harry! |
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Anders has joined the group as a Master student. Welcome Anders! |
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Andreas today has defended his Master thesis. Congratulations Andreas! |
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!
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.
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.
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.
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Andreas has joined the group as a Master student. Welcome Andreas! |
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.
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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! |
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!
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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! |
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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! |
We successfully moved the ion trap experiment from University of Innsbruck to Stockholm University. See below some pictures from the move.
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