Max Schaefer

Thrilled to see my PhD supervisor Michel Devoret win the 2025 Nobel Prize in Physics — so well deserved for a visionary scientist and inspiring mentor. His pioneering work made much of today’s superconducting-circuit quantum research possible.

#Quantum #NobelPrize

Clarke, Devoret and Martinis win 2025 Nobel Prize in Physics Scientists John Clarke, Michel Devoret and John Martinis won the 2025 Nobel Prize in Physics for "the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit", the award-giving body said on Tuesday.

Clarke, Devoret and Martinis win 2025 Nobel Prize in Physics reut.rs/3KHTfTs

Heekun Nho, Thomas Connolly, Pavel D. Kurilovich, Spencer Diamond, Charlotte G. L. B{\o}ttcher, Leonid I. Glazman, Michel H. Devoret
Recovery dynamics of a gap-engineered transmon after a quasiparticle burst
https://arxiv.org/abs/2505.08104

Had a great time at #APSGlobalSummit! Discussed unexpected resonances and sudden lifetime drops at high photon numbers in #KerrCat qubits. We ran experiments to explore the cause, and there's much to learn. Check out our findings here: arxiv.org/abs/2409.13113. Would love to hear your insights!

Excited to share our latest work at #APSGlobalSummit! I’ll be presenting on tunneling in a tunable asymmetric double-well Kerr parametric oscillator and its role in simulating proton tunneling in chemical reactions. Catch my talk (MAR-C33) Mon, Mar 17, 5:48–6:00 PM, Anaheim CC, Room 253C! #APS2025

Jakob G\"unther, Freek Witteveen, Alexander Schmidhuber, Marek Miller, Matthias Christandl, Aram Harrow
Phase estimation with partially randomized time evolution
https://arxiv.org/abs/2503.05647

Nam P. Vu, Daniel Dong, Xiaohan Dan, Ningyi Lyu, Victor Batista, Yuan Liu
A Computational Framework for Simulations of Dissipative Non-Adiabatic Dynamics on Hybrid Oscillator-Qubit Quantum Devices
https://arxiv.org/abs/2502.17820

Aniket Maiti, John W. O. Garmon, Yao Lu, Alessandro Miano, Luigi Frunzio, Robert J. Schoelkopf
A Linear Quantum Coupler for Clean Bosonic Control
https://arxiv.org/abs/2501.18025

LDPC-cat codes for low-overhead quantum computing in 2D - Nature Communications Implementing full quantum error correction incurs a significant hardware overhead. Here, the authors propose a quantum computing architecture combining superconducting cat qubits with 2D local LDPC co...

Happy to share our work with @anthony-leverrier.bsky.social, @christophe.vuillot.info, Jérémie Guillaud and Mazyar Mirrahimi on the LDPC-cat architecture was published in Nature Communications! Thanks to the reviewers for their useful feedback
www.nature.com/articles/s41...

Check out this paper by my friends and colleagues achieving an order of magnitude improvement in the QNDness of transmon readout

Check out this interesting theory paper on switching rates in the asymmetric/biased Kerr Parametric Oscillator

Exact amplitudes of parametric processes in driven Josephson circuits We present a general approach for analyzing arbitrary parametric processes in Josephson circuits within a single degree of freedom approximation. Introducing a systematic normal-ordered expansion for ...

My colleague's new work: a general method for the normal-ordered Hamiltonian expansion of arbitrary single-DOF potentials, yielding exact coefficients for driven Josephson circuits. This is crucial to analyze strongly driven systems like the Cat qubits. Check it out: arxiv.org/abs/2501.07784

Great set of Paul Bernays lectures by Michel Devoret at @ethzurich.bsky.social this week.
You will be able to listen to the recorded lectures soon by following this link: math.ethz.ch/news-and-eve... .
It was great to discuss with Michel and show him around at the labs.
Thanks for the visit!

Check out this exciting paper about the Kerr-cat qubit from my friends and colleagues!

Check out our new Quantum Device Lab (qudev.ethz.ch) paper on entangling #quantum error corrected logical qubits in superconducting circuits "Realizing Lattice Surgery on Two Distance-Three Repetition Codes with Superconducting Qubits" published on arXiv today ( arxiv.org/abs/2501.04612 ).
1/4

Circuits Galore! Check out our latest work demonstrating three new circuits for implementing the surface code: arxiv.org/abs/2412.14360 They all perform well below threshold on a device optimised for the standard surface code, but they each open up wild new possibilities for devices.

Over the past year I played a supporting role on experiments showing we have a flexibility in how we do QEC on a planar chip. We do a color code (arxiv.org/abs/2412.14256), and three interesting variations of the surface code circuit (arxiv.org/abs/2412.14360), all below threshold.

Mark your calendars!
The second big lecture series of the term on #quantum #science and #technology at @ethzurich.bsky.social will be given by one of the pioneers of mesoscopic physics and superconducting quantum circuits Michel Devoret.
- math.ethz.ch/news-and-eve...
Hope to see you there.

Meet Willow, our state-of-the-art quantum chip Our new quantum chip demonstrates error correction and performance that paves the way to a useful, large-scale quantum computer.

🌳 Excited to introduce Willow, Google Quantum AI’s latest chip. Willow 5x’s coherence times, beats the Surface Code QEC threshold, and the time to reproduce Willow's RCS on Frontier supercomputer is estimated at 10^25 years⏳! 👇 thread #Quantum #Physics #Science

blog.google/technology/r...

A Roadmap for Simulating Chemical Dynamics on a Parametrically Driven Bosonic Quantum Device Chemical reactions are commonly described by the reactive flux transferring the population from reactants to products across a double-well free energy barrier. Dynamics often involves barrier recrossi...

Thrilled to share our paper, "A Roadmap for Simulating Chemical Dynamics on a Parametrically Driven Bosonic Quantum Device," in The Journal of Physical Chemistry Letters! We explore Kerr-cat devices for simulating proton transfer, including in DNA base pairs. Read here: pubs.acs.org/doi/abs/10.1...