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Joachim Schäfer

Email: joschaef (at) ulb.ac.be
Phone: +32-2-650 29 56
Fax: +32-2-650 29 41
Address: QuIC - Ecole Polytechnique de Bruxelles
Université Libre de Bruxelles
50 av. F. D. Roosevelt - CP 165/59
B-1050 Bruxelles

Short biography

  • Born in 1984 in Mainz, Germany.
  • I started my physics studies at the Johannes-Gutenberg Universität, Mainz in 2003.
  • From summer 2006 to end of spring 2007 I did an Erasmus term at the Kungliga Tekniska Högskolan KTH, Stockholm, Sweden.
  • After my final exams I did the last year of my studies (the diploma thesis/“Diplomarbeit”) from beginning 2008 to beginning 2009, at our service QuIC under the direction of Nicolas J. Cerf in collaboration with Arno Rauschenbeutel (now head of the group Applied Quantum Physics in Vienna).
  • Since spring 2009 I am a PhD student at QuIC in the field of continuous variable communication

Research interests

  • Quantum Information Theory
  • Quantum Channels
  • Quantum Key Distribution with Continuous Variables
  • Quantum Repeaters


  • Théorie de l'Information (2009/2010)
  • Théorie de l'Information (2010/2011)
  • Mécanique Quantique I (2010/2011)
  • Mécanique Quantique I (2011/2012)
  • Information Theory (2011/2012)

Master Thesis

PhD Thesis


Gaussian classical capacity of Gaussian quantum channels (Proceedings Paper),
E. Karpov, J. Schäfer, R. Garcia-Patron, O. V. Pilyavets, and N. J. Cerf
Nanosystems: Physics, Chemistry, Mathematics 4, 496 (2013).
PDF file

Equivalence relations for the classical capacity of single-mode Gaussian quantum channels,
Joachim Schäfer, Evgueni Karpov, Raúl García-Patrón, Oleg V. Pilyavets and Nicolas J. Cerf,
Phys. Rev. Lett. 111, 030503 (2013),
DOI: 10.1103/PhysRevLett.111.030503,
PDF file, Supp. Mat., arXiv:1303.4939 [quant ph]

Gaussian matrix-product states for coding in bosonic communication channels,
Joachim Schäfer, Evgueni Karpov and Nicolas J. Cerf,
Phys. Rev. A 85, 012322 (2012),
DOI: 10.1103/PhysRevA.85.012322,
PDF file, arXiv:1201.0200 [quant ph]

Gaussian capacity of the quantum bosonic memory channel with additive correlated Gaussian noise,
Joachim Schäfer, Evgueni Karpov and Nicolas J. Cerf,
Phys. Rev. A 84, 032318 (2011),
DOI: 10.1103/PhysRevA.84.032318,
PDF file, arXiv:1011.4118 [quant ph]

Quantum water-filling solution for the capacity of Gaussian information channels (Proceedings Paper),
Joachim Schäfer, Evgueni Karpov and Nicolas J. Cerf,
Proceedings of SPIE, Vol. 7727, 77270J (2010),
DOI: 10.1117/12.854641,
PDF file

Capacity of a bosonic memory channel with Gauss-Markov noise,
Joachim Schäfer, David Daems, Evgueni Karpov and Nicolas J. Cerf,
Phys. Rev. A 80, 062313 (2009),
DOI: 10.1103/PhysRevA.80.062313,
PDF file, arXiv:0907.0982 [quant ph]