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Faculty of Mathematics



  • 2017-today: Draper's Company Junior Research Fellow, Pembroke College, University of Cambridge
  • 2017: EPSRC Doctoral Price Award
  • April-June 2016 and July-August 2017: Visiting Student Researcher, California Institute of Technology
  • 2015-today: Honorary Research Assistant, University College London
  • 2014-2017: PhD in Quantum Information, DAMTP, St John's College, University of Cambridge
  • 2012-2013: MASt in Pure Mathematics and Theoretical Physics, DPMMS, St John's College, University of Cambridge
  • 2011-2012: Cornell-Heidelberg fellow, Physics, Cornell University
  • 2008-2011: BSc in Physics, University of Heidelberg

Research Interest

I am researching the interplay between quantum mechanics and information theory, such as Hamiltonian complexity and quantum channel divisibility. I am particularly interested in the local Hamiltonian problem and related topics in condensed matter physics, and how systems described by local interactions are able to perform universal computation. My general interest ranges from quantum and high energy physics to pure mathematics, analysis and probability, as well as computer science, especially algorithms, machine learning, and simulations.

I also like neural networks and won the 2nd price in Microsoft's Quantum Challenge with a quantum data classifier, as well as an AI Grant for the search for new error correcting codes.


Publications and Preprints

Invited Talks and Conference Presentations

  • QuID 2018 in Zürich, Italy (invited lecture). Principles of Quantum Algorithms
  • QTML 2017 in Verona, Italy. Quantum Neural Networks: a Hamiltonian Complexity Approach
  • STRUCTURES, June 2017, in Heidelberg (invited talk): The Complexity of Translationally Invariant Spin Systems with Low Dimension. Joint work with Toby Cubitt, Maris Ozols, Stephen Piddock, and Elizabeth Crosson.
  • Heilbronn and QALGO Quantum Algorithms Meeting 2016 in Cambridge, UK: The Complexity of Translationally Invariant Spin Chains with Low Dimension. Joint work with Toby Cubitt and Maris Ozols.
  • QIP 2016 in Banff, Canada: The Complexity of Translationally Invariant Spin Chains with Low Local Dimension.
  • AQIS 2015 in Seoul, South Korea: The Complexity of Divisibility. Joint work with Toby Cubitt.
  • QIPC 2015 in Leeds, UK: The Complexity of Divisibility.
  • Further invited talks at group meetings and seminars at UCL (2015), Universidad Complutense de Madrid (2015 and 2018), University of Bristol (2016), Caltech (2016), Heidelberg (2017), and Amsterdam (2018).


  • QIP 2015 in Sydney, Australia: The Complexity of Divisibility.
  • Microsoft Faculty Summit 2016 in Seattle, USA: Quantum Neural Networks: a Hamiltonian Complexity Approach
  • YQIS 2016 in Barcelona, Spain, and QIP 2017 in Seattle, USA: The Complexity of Low-Dimensional Spin Lattices in 3D
  • QIP 2017 in Seattle, USA: Size Driven Quantum Phase Transitions  BEST POSTER AWARD
  • QIP 2017 in Seattle, USA: Increasing the Quantum UNSAT Penalty




Classifying data using near-term quantum devices
J Bausch
– Int. J. Quantum Inf. 1840001 (2018)
Analysis and limitations of modified circuit-to-Hamiltonian constructions
J Bausch, E Crosson
– Quantum
Size-driven quantum phase transitions
J Bausch, TS Cubitt, A Lucia, D Perez-Garcia, MM Wolf
– Proceedings of the National Academy of Sciences
The Complexity of Translationally-Invariant Spin Chains with Low Local Dimension.
J Bausch, T Cubitt, M Ozols
– Ann. Henri Poincar\'e (2017) 18(11), 3449-3513
The complexity of translationally-invariant low-dimensional spin lattices in 3D
J Bausch, S Piddock
– Journal of Mathematical Physics
The complexity of divisibility
J Bausch, T Cubitt
– Linear Algebra and its Applications
On the efficient calculation of a linear combination of chi-square random variables with an application in counting string vacua
J Bausch
– Journal of Physics A: Mathematical and Theoretical
Quantum Codes from Neural Networks
J Bausch, F Leditzky
Perturbation Gadgets: Arbitrary Energy Scales from a Single Strong Interaction
J Bausch
Undecidability of the Spectral Gap in One Dimension
J Bausch, T Cubitt, A Lucia, D Perez-Garcia
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Research Group

Centre for Quantum Information and Foundations




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