Quantum Computation with Schrödinger cat states

This project seeks to establish a radically new, alternative approach to realizing the fundamental building blocks of quantum computers with superconducting qubits. In the next 3 years, we plan to employ only a handful of realistic components to realize robust error-corrected logical quantum bits.

QUCOS announcement by Quantum Machines

What is QuCoS?

We aim to demonstrate the same level of protection provided by a few hundreds of qubits (with properties beyond the state of the art) in today’s mainstream approach of the so-called surface code architecture. Our alternative approach is known as cat codes, because it employs multiple interconnected high coherence cavity modes with non-linear dissipation, to encode a qubit in superpositions of Schrödinger cat states. Our project combines realizing the quantum processor architecture as well as the control system and the protocols that drive it, building towards a full-stack error-corrected quantum computer.

The partners in our collaboration form a strong synergetic group that has the full range of expertise needed to design and realize these systems, and to obtain these challenging goals. Furthermore, all partners of our project, including both industry and academia, have worked together and published works in the fields of quantum computing and quantum information processing. We aim to implement error protected qubits, fault tolerant operations, and demonstrate the scalability of this approach by realizing a repetition code. Our project will enable quantum experiments towards the ambitious and well-defined goal of constructing a logical qubit, on which we can perform gates, and most importantly, quantum error-correctio (QEC). All algorithms with theoretically proven quantum speedup require QEC, therefore, with this project we are realizing an essential building block of a European error corrected quantum processor.

QuCoS Group Picture
QuCoS Group Picture

QuCoS Meeting
Innsbruck

Who is involved?

University of Innsbruck UIBK

Gerhard Kirchmair

Gerhard Kirchmair

Coordinator
Teresa Hönigl-Decrinis

Teresa Hönigl-Decrinis

PostDoc
Desislava Atanasova

Desislava Atanasova

PhD Student

Ecole Normale Superieure de Lyon ENSL

Benjamin Huard

Benjamin Huard

PI
Antoine Marquet

Antoine Marquet

PhD Student

Ecole Normale Superieure de Paris QUANTIC1

Zak Leghtas

Zak Leghtas

PI
Clark Smith

Clark Smith

PostDoc
Alvise Borgognoni

Alvise Borgognoni

PhD Student

Karlsruher Institut Fur Technologie KIT

Ioan Pop

Ioan Pop

PI

Quantum Machines QM

Itamar Sivan

Itamar Sivan

CEO
Yonatan Cohen

Yonatan Cohen

CTO
Nissim Ofek

Nissim Ofek

Chief Engineer
Niv Drucker

Niv Drucker

Researcher
Lior Ella

Lior Ella

Researcher
Guy Kerem

Guy Kerem

Researcher
Ramon Szmuk

Ramon Szmuk

Researcher

National Institute For Research And Developement Of Isotopic And Molecular Technologies ITIM

Luiza Buimaga-Iarinca

Luiza Buimaga-Iarinca

PI
Christian Morari

Christian Morari

Researcher
Doru Cristian Sticlet

Doru Cristian Sticlet

Researcher
Liviu Zarbo

Liviu Zarbo

Researcher
Adrean Calborean

Adrean Calborean

Researcher

Publications

Dennis Willsch, Dennis Rieger, Patrick Winkel, Madita Willsch, Christian Dickel, Jonas Krause, Yoichi Ando, Raphaël Lescanne, Zaki Leghtas, Nicholas T. Bronn, Pratiti Deb, Olivia Lanes, Zlatko K. Minev, Benedikt Dennig, Simon Geisert, Simon Günzler, Sören Ihssen, Patrick Paluch, Thomas Reisinger, Roudy Hanna, Jin Hee Bae, Peter Schüffelgen, Detlev Grützmacher, Luiza Buimaga-Iarinca, Cristian Morari, Wolfgang Wernsdorfer, David P. DiVincenzo, Kristel
Observation of Josephson harmonics in tunnel junctions.
Francesco Valenti, Andrew N. Kanagin, Andreas Angerer, Luiza Buimaga-Iarinca, Cristian Morari, Jörg Schmiedmayer, and Ioan M. Pop
Hydrogen crystals reduce dissipation in superconducting resonators
A. Marquet, A. Essig, J. Cohen, N. Cottet, A. Murani, E. Albertinale, S. Dupouy, A. Bienfait, T. Peronnin, S. Jezouin, R. Lescanne, and B. Huard
Autoparametric Resonance Extending the Bit-Flip Time of a Cat Qubit up to 0.3 s
Daria Gusenkova, Francesco Valenti, Martin Spiecker, Simon Günzler, Patrick Paluch, Dennis Rieger, Larisa-Milena Pioraş-Ţimbolmaş, Liviu P. Zârbo, Nicola Casali, Ivan Colantoni, Angelo Cruciani, Stefano Pirro, Laura Cardani, Alexandru Petrescu, Wolfgang Wernsdorfer, Patrick Winkel, Ioan M. Pop
Operating in a deep underground facility improves the locking of gradiometric fluxonium qubits at the sweet spots
W. C. Smith, M. Villiers, A. Marquet, J. Palomo, M. R. Delbecq, T. Kontos, P. Campagne-Ibarcq, B. Douçot, and Z. Leghtas
Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing
U. Réglade, A. Bocquet, R. Gautier, J. Cohen, A. Marquet, E. Albertinale, N. Pankratova, M. Hallén, F. Rautschke, L.-A. Sellem, P. Rouchon, A. Sarlette, M. Mirrahimi, P. Campagne-Ibarcq, R. Lescanne, S. Jezouin & Z. Leghtas
Quantum control of a cat qubit with bit-flip times exceeding ten seconds
C. Berdou, A. Murani, U. Réglade, W.C. Smith, M. Villiers, J. Palomo, M. Rosticher, A. Denis, P. Morfin, M. Delbecq, T. Kontos, N. Pankratova, F. Rautschke, T. Peronnin, L.-A. Sellem, P. Rouchon, A. Sarlette, M. Mirrahimi, P. Campagne-Ibarcq, S. Jezouin, R. Lescanne, and Z. Leghtas
One Hundred Second Bit-Flip Time in a Two-Photon Dissipative Oscillator

Under review

Antoine Marquet, Simon Dupouy, Ulysse Réglade, Antoine Essig, Joachim Cohen, Emanuele Abertinale, Audrey Bienfait, Théau Peronnin, Sébastien Jezouin, Raphaël Lescanne, Benjamin Huard
Harnessing two-photon dissipation for enhanced quantum measurement and control
Ian Yang, Thomas Agrenius, Vasilisa Usova, Oriol Romero-Isart, Gerhard Kirchmair
Hot Schrödinger Cat States
W. C. Smith, A. Borgognoni, M. Villiers, E. Roverc'h, J. Palomo, M. R. Delbecq, T. Kontos, P. Campagne-Ibarcq, B. Douçot, Z. Leghtas
Spectral signature of high-order photon processes mediated by Cooper-pair pairing
Diego Ruiz, Jérémie Guillaud, Anthony Leverrier, Mazyar Mirrahimi, Christophe Vuillot
LDPC-cat codes for low-overhead quantum computing in 2D
Desislava G. Atanasova, Ian Yang, Teresa Hönigl-Decrinis, Daria Gusenkova, Ioan M. Pop, Gerhard Kirchmair
In-situ tunable interaction with an invertible sign between a fluxonium and a post cavity

Patents

Product development

Videos

Panel on Quantum Technologies

Dr. Liviu Zarbo, Radio Romania, 12.05.2021

To Facebook
Panel on Quantum Technologies
QISKIT seminar on Fluxonium qubits

QISKIT seminar on Fluxonium qubits

Ioan Pop, Daria Gusenkova & Martin Spiecker

To YouTube

Google Quantum AI on Fluxonium qubits made from Granular aluminium

Ioan Pop

To YouTube
Google Quantum AI on Fluxonium qubits made from Granular aluminium

Public Outreach

The consortium was part of the following public outreach activities
Quantum Future Academy 2020
European Quantum week
The Second Quantum Revolution: from Concepts to Quantum Hardware, Dr. Liviu Zarbo, 14.04.2021, World Quantum Day, Organized by ITIM, Transilvania Quantum, Transylvania University, Brasov
Tag der Physik (Open house day Institute for Physics), Gerhard Kirchmair, 21.04.2022, University of Innsbruck
Pint of Science, Gerhard Kirchmair, 11.05.2022
4. Presentation for High school teachers April 2022, ENS Paris, Zaki Leghtas Gender of first/corresponding author
This research was funded in whole or in part by the Austrian Science Fund (FWF), Grant DOI 10.55776/W1259, and the 10.55776/I4395 QuantERA grant QuCOS