Daniel Brod

Daniel Brod's picture

Area of Research:

Research Interests

My main research interests are on intermediate models of quantum computation, classical simulation of quantum circuits, quantum computation with linear optics and foundations of quantum computing in general.

More specifically, I have worked on linear-optical quantum computing and BosonSampling, the latter which is an intermediate model of quantum computation expected to not be universal for quantum computing nor classically simulable. Although BosonSampling is expected to be much weaker, from a computational point of view, than universal quantum computers, its promised ease of implementation has recently attracted much attention from the experimental quantum optics community, which regard it as an intermediate milestone on the way to universal fault-tolerant quantum computers.

I have also worked on matchgates, a restricted set of 2-qubit gates which are related to the dynamics of noninteracting fermions, and which are known to be efficiently classically simulable. In particular, I investigated several ways to bridge the gap between classically simulable and quantum universal in the context of matchgates.

Besides these models which I have worked on, I am also generally interested in intermediate models of quantum computing, i.e. those which are not classically simulable nor quantum universal, such as DQC1, constant-depth quantum circuits, circuits of commuting gates, etc., as well as other restricted (e.g. Clifford circuits) or alternative (e.g. topological or measurement-based) models of quantum computing.

Recent Publications

  • D. J. Brod, J. Combes, A passive CPHASE gate via cross-Kerr nonlinearities, Phys. Rev. Lett. 117, 080502 (2016) - arXiv: 1604.04278 [quant-ph]
  • D. J. Brod, J. Combes, J. Gea-Banacloche, Two photons co- and counter-propagating through N cross-Kerr sites, Phys. Rev. A 94, 023833 (2016) - arXiv: 1604.03914 [quant-ph]
  • D. J. Brod, Efficient classical simulation of matchgate circuits with generalized inputs and measurements, Phys. Rev. A 93, 062332 (2016) - arXiv: 1602.03539 [quant-ph]
  • S. Aaronson, D. J. Brod, BosonSampling with Lost Photons, Phys. Rev. A 93, 012335 (2016) - arXiv: 1510.05245 [quant-ph]
  • M. Bentivegna, N. Spagnolo, C. Vitelli, F. Flamini, N. Viggianiello, L. Latmiral, P. Mataloni, D. J. Brod, E. F. Galvão, A. Crespi, R. Ramponi, R. Osellame, F. Sciarrino, Experimental scattershot boson sampling, Science Advances 1, e1400255 (2015) - arXiv: 1505.03708 [quant-ph]
  • D. J. Brod, Complexity of simulating constant-depth BosonSampling, Phys. Rev. A 91, 042316 (2015) - arXiv: 1412.6788 [quant-ph]


  • Computational Complexity of constant-depth BosonSampling, at the V Quantum Information Workshop, Paraty, Brazil
  • PIRSA:14010085, The computational power of matchgates and the XY interaction on arbitrary graphs, 2014-01-08, Perimeter Institute Quantum Discussions