Optical systems are the most suitable physical systems for transmitting quantum information over large distance. What is more, recent years have seen a remarkable progress in the understanding of performing precise quantum state manipulation of optical systems, both in the discrete variable setting involving polarization or time-bin encoding as well as so-called continuous variables. We are concerned with understanding what quantum state manipulation is possible after all, often in close collaboration with leading experimentalists.

Selected group publications

• Reliable quantum certification for photonic quantum technologies
  Nature Communications 6, 8498 (2015)

• Experimental implementation of the optimal linear-optical controlled phase gate
  Physical Review Letters 106, 013602 (2011)

• Directly estimating non-classicality
  Physical Review Letters 106, 010403 (2011)

• Photonic polarization gears for ultra-sensitive angular measurements
  Nature Communications 4, 2432 (2013)

• Optical generation of matter qubit graph states
  New Journal of Physics 7, 194 (2005) 

• Optimizing linear optics quantum gates
  Physical Review Letters 95, 040502 (2005) 

• Measuring measurement
  Nature Physics 5, 27 (2009)

• Distillation of continuous-variable entanglement with optical means
  Annals of Physics (NY) 311, 431 (2004) 

• Driving non-Gaussian to Gaussian states with linear optics
  Physical Review A 67, 062320 (2003)

• The entangling power of passive optical elements
  Physical Review Letters 90, 047904 (2003) 

• Gaussification and entanglement distillation of continuous variable systems: a unifying picture
  Physical Review Letters 108, 020501 (2012)

• Preparing the bound instance of quantum entanglement
  Physical Review Letters 107, 240503 (2011)

Group reviews

• Advances in quantum teleportation
  Nature Photonics 9, 641 (2015)
• Introduction to the basics of entanglement theory in continuous-variable systems
  International Journal of Quantum Information 1, 479 (2003) 
• Gaussian quantum channels
  In: Continuous-variable quantum information science, Eds. E. Polzik, N. Cerf, G. Leuchs, (Imperial College Press, 2007)