Distributed Quantum Systems

In our group we work on developing methods to establish entanglement between remote quantum systems and using that capability to realize new scientific and technological applications. Our remote quantum systems are equivalent to registers of spins, in which entanglement can be stored and processed, that are linked together using photons.  We would like to develop such quantum networks over distances from a few meters, in order to study scalable many-body quantum systems, up to thousands of kilometers, for global quantum communication and sensing networks. Our key research questions are:

• How can we distribute, store and grow entanglement between remote locations?
• What are the most promising applications of distributed entanglement and how can we realize them in the near future?
  
  

In our lab we focus on developing spin registers encoded into arrays of trapped atomic ions. The singularly-ionized atoms are held in a radio-frequency linear Paul trap. Each atom encodes a quantum spin, or quantum bit, and universal quantum processing can be realized over the spin register using laser-driven interactions. An optical cavity integrated around the trap allows for efficiently interfacing the spins with single photons.  The image below shows our cavity-integrated ion-trap. We also develop non-linear optical systems for interconverting the wavelengths of photons from ion-compatible values to the special value of 1550nm. This `Telecom C-band’ wavelength is used by the global classical telecommunications industry, suffers minimal loss whilst travelling through optical fibers and is the ideal value for a future quantum communication standard.

View into the vacuum chamber. The ion trap is made of gold-coated titanium electrodes and is attached to the top of the vacuum chamber. The optical cavity is formed by two mirrors in bluish titanium holders and sits on piezo stacks for cavity length control (the four wires supplying voltage to the piezos are visible). The cavity is attached, via translation stages (not shown), to the bottom vacuum chamber flange.

Recent news

• The EU has written an article here on our work within the project 'quantum internet alliance'
• We have PhD and Postdoc positions available. Please email us directly at This email address is being protected from spambots. You need JavaScript enabled to view it.
• There has been quite some press about our repeater node paper. e.g., this viewpoint in Physics, this article in Optica and this article in Physics World.
• May 2023. Our repeater node paper was published in Physical Review letters, here.
• Feb 2023. Our paper on realizing a quantum repeater node [arXiv:2210.05418] was accepted for publication in Physical Review letters.
• Feb 2023. Our paper on entangling two ions in remote buildings was published in Physical Review letters. This work was carried out in close collaboration with the groups of Prof. Tracy Northup and of Prof. Nicolas Sangouard. Congratulations to the teams! Phys. Rev. Lett. 130, 050803 (2023) and  arXiv:2208.14907 (see press release and editor's choice article).

Our Team

This email address is being protected from spambots. You need JavaScript enabled to view it. (Master)

This email address is being protected from spambots. You need JavaScript enabled to view it. (Master)

This email address is being protected from spambots. You need JavaScript enabled to view it. (PhD)

This email address is being protected from spambots. You need JavaScript enabled to view it. (Administrative assistant)

This email address is being protected from spambots. You need JavaScript enabled to view it. (PhD)

This email address is being protected from spambots. You need JavaScript enabled to view it. (PhD)

This email address is being protected from spambots. You need JavaScript enabled to view it. (PhD)

Vojtech Krcmarsky (PhD)

This email address is being protected from spambots. You need JavaScript enabled to view it. (Postdoc)

This email address is being protected from spambots. You need JavaScript enabled to view it. (Project Leader)

PhD defense of Dr. Meraner. From left to right: Ben Lanyon, Josef Schupp, Zhe Koong, Armin Winkler, Marco Canteri, Viktor Krutianskii, Martin Meraner, James Bate, Vojtech Krcmarksy, Tabea Stroinski, Johannes Helgert

Former project members

Dr. Zhe Koong (Postdoc), now at the University of Oxford

Dr. Martin Meraner (PhD), now at BERNARD group

Dr. Josef Schupp (PhD), now at Alpine Quantum Technologies

Helene Hainzer (Master Student), now in the group of Ch. Roos

Dr. Muir Kumph (Postdoc), now IBM Watson Research Centre

Contact

Our new labs are on the 1st floor of the Viktor-Franz-Hess Haus, building TE025 on the Technik campus of the University of Innsbruck. Technikerstrasse 25, A-6020 Innsbruck, Austria.

Tel: +43-512-507-52900

Publications

• A telecom-wavelength quantum repeater node based on a trapped-ion processor
  Victor Krutyanskiy, Marco Canteri, Martin Meraner, James Bate, Vojtech Krcmarsky, Josef Schupp, Nicolas Sangouard, Ben P. Lanyon
  arXiv:2210.05418
• Entanglement of trapped-ion qubits separated by 230 meters
  V. Krutyanskiy, M. Galli, V. Krcmarsky, S. Baier, D. A. Fioretto, Y. Pu, A. Mazloom, P. Sekatski, M. Canteri, M. Teller, J. Schupp, J. Bate, M. Meraner, N. Sangouard, B. P. Lanyon, T. E. Northup
  Phys. Rev. Lett. 130, 050803 (2023) and  arXiv:2208.14907 (see press release and editor's choice)
• Interface between Trapped-Ion Qubits and Traveling Photons with Close-to-Optimal Efficiency
  J. Schupp, V. Krcmarsky, V. Krutyanskiy, M. Meraner, T.E. Northup, and B.P. Lanyon
  PRX Quantum 2, 020331 (2021)
• Indistinguishable photons from a trapped-ion quantum network node
  M. Meraner, A. Mazloom, V. Krutyanskiy, V. Krcmarsky, J. Schupp, D. A. Fioretto, P. Sekatski, T. E. Northup, N. Sangouard, and B. P. Lanyon
  Phys. Rev. A 102, 052614 (2020)
• Light-matter entanglement over 50 km of optical fibre
  V. Krutyanskiy, M. Meraner, J. Schupp, V. Krcmarsky, H. Hainzer & B. P. Lanyon
  npj Quantum Information, volume 5, Article number: 72 (2019)
• Deterministic quantum state transfer between remote qubits in cavities
  B. Vogell, B. Vermersch, T. E. Northup, B. P. Lanyon, C. A. Muschik
  Quantum Sci. Technol. 2 045003, arXiv:1704.06233

• "Polarisation-preserving photon frequency conversion from a trapped-ion-compatible wavelength to the telecom C-band"
  V. Krutyanskiy, M. Meraner, J. Schupp and B. P. Lanyon
  Appl. Phys. B 123, 228 (2017) (Open access)
• "Quantum repeaters based on trapped ions with decoherence-free subspace encoding"
  M. Zwerger, B. P. Lanyon, T. E. Northup, C. A. Muschik, W. Dür and N. Sangouard
  Quantum Sci. Technol.2 (2017),arXiv:1611.07779

Theses

PhD

• Martin Meraner, A photonic quantum interface between trapped ions and the telecom C-band, 2022, Download
• Josef Schupp, Interface between trapped-ion qubits and travelling photons with close-to-optimal efficiency, Download

Master

• Helene Hainzer, Laser locking for trapped-ion quantum networks, 2018, Download
• Marco Canteri, Single-atom-focused laser for photon generation and qubit control, 2020, Download
• Armin Winkler, Frequency Stabilization of a 729 nm Ti:Sa Laser for Qubit Manipulation in Trapped Calcium Ions, 2023, Download