About

Jens Koch is a Professor of Physics and Astronomy at Northwestern University. He earned his Ph.D. from Freie Universität Berlin, Germany, in 2006, and his B.S. in Physics from Universität Kaiserslautern in 2000. His research focuses on theoretical condensed matter physics, quantum optics, and quantum information. He is particularly interested in strongly correlated quantum systems, quantum information processing with solid-state devices, and quantum coherence in mesoscopic systems. A central theme of his work is the study of artificial quantum systems—man-made systems that behave quantum mechanically and are used to explore new quantum effects not realized in nature. Professor Koch has made significant contributions to the development of superconducting qubits and circuit quantum electrodynamics (cQED). His research includes the design and control of superconducting circuits patterned on microchips, such as the transmon and fluxonium devices, and the demonstration of the first two-qubit gates in cQED. His group explores complex superconducting circuits with potential for increased coherence and topological protection. Additionally, his research investigates arrays of coupled cQED systems as a means to study strongly correlated systems of photons or polaritons. He collaborates closely with experimental groups, notably with Andrew Houck at Princeton, to advance the understanding and application of these quantum systems.

Research topics

• Computer Science
• Quantum mechanics
• Electrical engineering
• Philosophy
• Algorithm
• Physics

Selected publications

• Protecting a bosonic qubit with autonomous quantum error correction

  Nature · 129 citations

  • Computer Science
  • Computer Science
  • Physics

  Abstract To build a universal quantum computer from fragile physical qubits, effective implementation of quantum error correction (QEC)1 is an essential requirement and a central challenge. Existing demonstrations of QEC are based on an active schedule of error-syndrome measurements and adaptive recovery operations2, 3, 4, 5, 6, 7 that are hardware intensive and prone to introducing and propagating errors. In principle, QEC can be realized autonomously and continuously by tailoring dissipation within the quantum system1, 8, 9, 10, 11, 12, 13, 14, but so far it has remained challenging to achieve the specific form of dissipation required to counter the most prominent errors in a physical platform. Here we encode a logical qubit in Schrödinger cat-like multiphoton states15 of a superconducting cavity, and demonstrate a corrective dissipation process that stabilizes an error-syndrome operator: the photon number parity. Implemented with continuous-wave control fields only, this passive protocol protects the quantum information by autonomously correcting single-photon-loss errors and boosts the coherence time of the bosonic qubit by over a factor of two. Notably, QEC is realized in a modest hardware setup with neither high-fidelity readout nor fast digital feedback, in contrast to the technological sophistication required for prior QEC demonstrations. Compatible with additional phase-stabilization and fault-tolerant techniques16, 17, 18, our experiment suggests quantum dissipation engineering as a resource-efficient alternative or supplement to active QEC in future quantum computing architectures.

  DOI

• Christine Windbichler zum 70. Geburtstag

  De Gruyter eBooks · 2020

  • Philosophy
  DOI

Recent grants

• CAREER: Quantum Phases and Non-Equilibrium Dynamics of Strongly Correlated Photons

  NSF · $500k · 2011–2017

Frequent coauthors

• Andrew Houck

  58 shared

• Uwe Hüffer

  58 shared

• David Schuster

  Electronics for Imaging (United States)

  48 shared

• Herausgegeben Von

  University of Bern

  46 shared

• Jochen Vetter

  36 shared

• Stephan Harbarth

  35 shared

• Mathias Habersack

  30 shared

• Volker Emmerich

  29 shared

Education

• Ph.D.

  Freie Universität Berlin

  2006

• B.S.

  Universität Kaiserslautern

  2000

Similar researchers at Northwestern University

• Mercouri G. Kanatzidish-205
• Chad Mirkinh-189
• Omar Farhah-184
• Tobin J. Marksh-176
• Joseph Hupph-171