Johannes Majer

Welcome to my webpage. I am a quantum physicist working at the forefront of hybrid quantum systems, combining superconducting circuits and spin ensembles to explore new frontiers in quantum information. My group is part of the Division of Quantum Physics and Quantum Information at the University of Science and Technology of China.

My path into quantum physics began in Switzerland, where I studied at ETH Zurich (ETHZ) and graduated in 1997. I then moved to the Netherlands to pursue my PhD at TU Delft under the supervision of Hans Mooij — one of the pioneers of superconducting quantum circuits — completing my thesis "Superconducting Quantum Circuits" in 2002. Afterwards, I joined the group of Rob Schoelkopf at Yale University, where we coupled superconducting qubits to microwave cavities and helped establish the field of circuit QED — today one of the leading platforms for quantum computing.

Contact Information

Prof. Dr. Johannes Majer
Xiupu Road 99
University of Science and Technology
Shanghai Research Institute
Pudong New District

201315, Shanghai

P. R. China

Email: johannes [at] majer [dot] ch

Recent News

January, 2020

In 2020 I started a new lab at the Division of Quantum Physics and Quantum Information of the University of Science and Technology of China. If you interested in joining the lab, please contact me.

September 4th, 2018

We measured superradiance with our hybrid system. The article has just appeared in Nature Physics:

Superradiant emission from colour centres in diamond
Andreas Angerer, Kirill Streltsov, Thomas Astner, Stefan Putz, Hitoshi Sumiya, Shinobu Onoda, Junichi Isoya, William J. Munro, Kae Nemoto, Jörg Schmiedmayer & Johannes Majer
https://www.nature.com/articles/s41567-018-0269-7

Please refer to the press release of the TU Wien
https://www.tuwien.ac.at/aktuelles/news_detail/article/126159/

Check out the coverage at science.orf.at, der Standard

February 12th, 2018

Solid-state electron spin lifetime limited by phononic vacuum modes
T. Astner, J. Gugler, A. Angerer, S. Wald, S. Putz, N. J. Mauser, M. Trupke, H. Sumiya, S. Onoda, J. Isoya, J. Schmiedmayer, P. Mohn & J. Majer
Nature Materials 17, 313–317 (2018)

https://www.tuwien.ac.at/de/aktuelles/news_detail/article/125614/

December 8th, 2017

Ultralong relaxation times in bistable hybrid quantum systems
Andreas Angerer, Stefan Putz, Dmitry O. Krimer, Thomas Astner, Matthias Zens, Ralph Glattauer, Kirill Streltsov, William J. Munro, Kae Nemoto, Stefan Rotter, Jörg Schmiedmayer, and Johannes Majer
Science Advances 3, (2017)
DOI: 10.1126/sciadv.1701626

April 10, 2017

We managed to couple two distant diamonds with a superconducting cavity. The work is published in Physical Review Letters and is chosen as an "Editor's Suggestion"
Coherent Coupling of Remote Spin Ensembles via a Cavity Bus
T. Astner, S. Nevlacsil, N. Peterschofsky, A. Angerer, S. Rotter, S. Putz, J. Schmiedmayer, and J. Majer
Phys. Rev. Lett. 118, 140502 (2017)

You find more information and an explenation for a general audience on the TU Wien Homepage, in German http://www.tuwien.ac.at/aktuelles/news_detail/article/124834/ and in English http://www.tuwien.ac.at/en/news/news_detail/article/124834/ (Photo: Thomas Srdinko)

November 21, 2016

Our work on the "Spectral hole burning and its application in microwave photonics" has now appeared in Nature Photonics:
Spectral hole burning and its application in microwave photonics
Stefan Putz, Andreas Angerer, Dmitry O. Krimer, Ralph Glattauer, William J. Munro, Stefan Rotter, Jörg Schmiedmayer, Johannes Majer
Nature Photonics 11, 36–39 (2017)

You find more information on the TU Wien Homepage. http://www.tuwien.ac.at/aktuelles/news_detail/article/124550/

July 21, 2016

We have demonstrade a novel cavity with homogenous coupling:
Collective strong coupling with homogeneous Rabi frequencies using a 3D lumped element microwave resonator
Andreas Angerer, , Thomas Astner, Daniel Wirtitsch, Hitoshi Sumiya, Shinobu Onoda, Junichi Isoya, Stefan Putz, and Johannes Majer
Appl. Phys. Lett. 109, 033508 (2016)

November 12, 2015

Smooth Optimal Quantum Control for Robust Solid-State Spin Magnetometry
Tobias Nöbauer, Andreas Angerer, Bj\"orn Bartels, Michael Trupke, Stefan Rotter, J\"org Schmiedmayer, Florian Mintert, and Johannes Majer
Phys. Rev. Lett. 115, 190801 (2015)

You find more information on the TU Wien Homepage. https://www.tuwien.ac.at/aktuelles/news_detail/article/9775/

August 18, 2014

Today our work on the cavity protection effect has been published in Nature Physics:
Protecting a spin ensemble against decoherence in the strong-coupling regime of cavity QED, S. Putz, D. O. Krimer, R. Amsüss, A. Valookaran, T. Nöbauer, J. Schmiedmayer, S. Rotter, J. Majer, Nature Physics (2014) doi:10.1038/nphys3050

Also see the News and Views article by Klaus Molmer Quantum memory: Needle in a haystack

You find more information on the TU Wien Homepage. "Cavity Protection Effect" macht Quanteninformation langlebig

July 10, 2014

Our recent proposal for realizing a Dicke lattice model in hybrid quantum system has been published in PRL.
Phys. Rev. Lett. 113, 023603

June 4, 2012

PhD position available: There is a PhD position within the Solids4Fun doctoral program available. http://solidfun.tuwien.ac.at

May 2, 2012

Our paper on "Strong magnetic coupling of an inhomogeneous nitrogen-vacancy ensemble to a cavity" has been published in Physical Review A: Phys. Rev. A 85, 053806 (2012)

August 8, 2011

Our paper on "Cavity QED with Magnetically Coupled Collective Spin States" has been published in Physical Review Letters: Phys. Rev. Lett. 107, 060502 (2011)
You can find more information in german on the TU Wien Presseaussendung.

April 20, 2011

I have received a TOP research grant from the TU Wien:
TU setzt neue Impulse für Spitzenforschung

June 29, 2009

Our article "Demonstration of two-qubit algorithms with a superconducting quantum processor" appeared online in Nature.
You can find more information in german on the TU Wien website Presseaussendung.

May, 2009

I wrote an article for a general audience in german which appeared in the SEV Bulletin. The SEV Bulleting is the official publication of the electrosuisse, which is the Swiss association for electrical engineering, power and information technologies.
Quantum Computing.pdf.

Sept 15, 2008

Our proposal for "Strong magnetic coupling of an ultracold gas to a superconducting waveguide cavity" appeared on the arXiv arXiv:0809.2552.

Sept 26, 2007

The cavity bus paper has appeared in this weeks issue of nature and is featured on the cover.

Sept 19, 2007

Our article on the the generation of single microwave photons is published in this weeks issue of Nature Magazin. For more information please refere to the Schoelkopf Lab Webpage.

Sept 13, 2007

Our work on coupling qubits via the cavity bus is now available on the arXive.

Publications List

Check out my Google Scholar Profile, ResearcherID, arXiv.org

• Quantum Computing
  Johannes Majer
  SEV Bulletin, , 5 (2009), electrosuisse (Swiss association for electrical engineering, power and information technologies) Quantum Computing.pdf
This paper explains in lay-mans terms the working principle of a quantum computer and the state-of-the-art of qubit research.
• Reversible state transfer between superconducting qubits and atomic ensembles
  David Petrosyan, Guy Bensky, Gershon Kurizki, Igor Mazets, Johannes Majer, and Jorg Schmiedmayer
  Phys. Rev. A 79, 040304 (2009), 10.1103/PhysRevA.79.040304, arXiv:0902.0881.
• Suppressing charge noise decoherence in superconducting charge qubits
  J. A. Schreier, A. A. Houck, Jens Koch, D. I. Schuster, B. R. Johnson, J. M. Chow, J. M. Gambetta, J. Majer, L. Frunzio, M. H. Devoret, S. M. Girvin, and R. J. Schoelkopf
  Phys. Rev. B 77, 180502 (2008), 10.1103/PhysRevB.77.180502, arXiv:0712.3581.
• Charge-insensitive qubit design derived from the Cooper pair box
  Jens Koch, Terri M. Yu, Jay Gambetta, A. A. Houck, D. I. Schuster, J. Majer, Alexandre Blais, M. H. Devoret, S. M. Girvin, and R. J. Schoelkopf
  Phys. Rev. A 76, 042319 (2007), 10.1103/PhysRevA.76.042319, arXiv:cond-mat/0703002.
• Coupling Superconducting Qubits via a Cavity Bus
  J. Majer, J. M. Chow, J. M. Gambetta, Jens Koch, B. R. Johnson, J. A. Schreier, L. Frunzio, D. I. Schuster, A. A. Houck, A. Wallraff, A. Blais, M. H. Devoret, S. M. Girvin, and R. J. Schoelkopf
  Nature 449, 443-447 (2007), doi:10.1038/nature06184, arXiv:0709.2135.
• Introducing the Transmon: a new superconducting qubit from optimizing the Cooper Pair Box
  Jens Koch, Terri M. Yu, Jay Gambetta, A. A. Houck, D. I. Schuster, J. Majer, Alexandre Blais, M. H. Devoret, S. M. Girvin, R. J. Schoelkopf
  arXiv:cond-mat/0703002.
• Generating Single Microwave Photons in a Circuit
  A. A. Houck, D. I. Schuster, J. M. Gambetta, J. A. Schreier, B. R. Johnson, J. M. Chow J. Majer, L. Frunzio, M. H. Devoret, S. M. Girvin and R. J. Schoelkopf
  Nature 449, 328-331 (2007), doi:10.1038/nature06126, arXiv:cond-mat/0702648.
• Resolving photon number states in a superconducting circuit
  D. I. Schuster, A. A. Houck, J. A. Schreier, A. Wallraff, J. M. Gambetta, A. Blais, L. Frunzio, J. Majer, B. Johnson, M. H. Devoret, S. M. Girvin, R. J. Schoelkopf
  Nature 445, 515 - 518 (2007), doi:10.1038/nature05461, arXiv:cond-mat/0608693.
• Qubit-photon interactions in a cavity: Measurement-induced dephasing and number splitting
  Jay Gambetta, Alexandre Blais, D. I. Schuster, A. Wallraff, L. Frunzio, J. Majer, M. H. Devoret, S. M. Girvin, and R. J. Schoelkopf
  Phys. Rev. A 74, 042318 (2006), doi:10.1103/PhysRevA.74.042318, arXiv:cond-mat/0602322.
• Approaching Unit Visibility for Control of a Superconducting Qubit with Dispersive Readout
  A. Wallraff, D. I. Schuster, A. Blais, L. Frunzio, J. Majer, M. H. Devoret, S. M. Girvin, and R. J. Schoelkopf
  Phys. Rev. Lett. 95, 060501 (2005), doi:10.1103/PhysRevLett.95.060501, arXiv:cond-mat/0502645.
• AC Stark Shift and Dephasing of a Superconducting Qubit Strongly Coupled to a Cavity Field
  D. I. Schuster, A. Wallraff, A. Blais, L. Frunzio, R.-S. Huang, J. Majer, S. M. Girvin, and R. J. Schoelkopf
  Phys. Rev. Lett. 94, 123602 (2005), doi:10.1103/PhysRevLett.94.123602, arXiv:cond-mat/0408367.
• Backaction effects of a SSET measuring a qubit spectroscopy and ground State measurement
  B. Turek, J. Majer, A. Clerk, S. Girvin, A. Wallraff, K. Bladh, D. Gunnarsson, T. Duty, P. Delsing, R. J. Schoelkopf
  IEEE Transactions on Applied Superconductivity, 15, 880 - 883 (2005), doi:10.1109/TASC.2005.850096.
• Fabrication and characterization of superconducting circuit QED devices for quantum computation
  L. Frunzio, A. Wallraff, D. Schuster, J. Majer, R. Schoelkopf
  IEEE Transactions on Applied Superconductivity, 15, 860 - 863 (2005), doi: 10.1109/TASC.2005.850084, arXiv:cond-mat/0411708.
• Spectroscopy on two coupled flux qubits
  J. B. Majer, F. G. Paauw, A. C. J. ter Haar, C. J. P. M. Harmans, J. E. Mooij
  Phys. Rev. Lett. 94 , 090501 (2005), doi:10.1103/PhysRevLett.94.090501, arXiv:cond-mat/0308192.
• Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics
  A. Wallraff, D. I. Schuster, A. Blais, L. Frunzio, R.- S. Huang, J. Majer, S. Kumar, S. M. Girvin, R. J. Schoelkopf
  Nature 431, 162 (2004), doi:10.1038/nature02851, arXiv:cond-mat/0407325.
• Superconducting Quantum Circuits
  Johannes Majer
  PhD Thesis
• Quantum Ratchet Effect for Vortices
  J. B. Majer, J. Peguiron, M. Grifoni, M. Tusveld, and J. E. Mooij
  Phys. Rev. Lett. 90 , 056802 (2003), doi:10.1103/PhysRevLett.90.056802, arXiv:cond-mat/0308192.
• Quantum Ratchets with Few Bands below the Barrier
  M. Grifoni, M. S. Ferreira, J. Peguiron, and J. B. Majer
  Phys. Rev. Lett. 89 , 146801 (2002), doi:10.1103/PhysRevLett.89.146801, arXiv:cond-mat/0208549.
• Simple phase bias for superconducting circuits
  J. B. Majer, J. R. Butcher, and J. E. Mooij
  Appl. Phys. Lett. 80 , 3638 (2002), doi:10.1063/1.1478150, arXiv:cond-mat/0108266.

PhD Thesis

Superconducting Quantum Circuits
Johannes B. Majer
ISBN 90-407-2360-5
Published by Delft University Press.

You can download my thesis from a dedicated website which also contains some additional online material. My thesis can also be purchased from Amazon or Barnes & Noble.