With photonic quantum computers, quantity is no substitute for quality (article in PRL by alumnus Jelmer Renema)


Scientists around the world are racing to be the first to demonstrate the power of quantum computers by using one to solve a specially selected mathematical problem. The problem needs to be easy for a quantum computer but also hard enough for a regular computer that the quantum computer will be able to solve it far earlier than the classic computer.

One such problem that can demonstrate the power of quantum computers is boson sampling, which involves interference from particles of light (i.e. photons). Dutch Physicist Jelmer Renema has shown that the photons involved need to meet a minimum standard of quality: if they are of lesser quality, the quantum computer will have no advantage over classic computers in terms of its calculating power. Renema's results have major consequences for those who are attempting to build an optical quantum computer. Whereas scientists had previously assumed that larger numbers of photons could compensate for imperfections, that no longer appears not to be the case. In other words: quantity is no substitute for quality. This means that scientists who are in the process of building such quantum machines will need to focus on photon sources that provide high-quality photons rather than on those that simply provide mass quantities of photons, as has been the trend in recent years.

Jelmer Renema carried out the research as a Rubicon Fellow during a two-year appointment with Department of Physics at Oxford University. The research was published in Physical Review Letters on 30 May. The article can be read here.

About Jelmer Renema

Jelmer Renema is a physicist with a PhD in quantum optics from Leiden University. After a two-year stay at Oxford University, he is currently doing postdoctoral research in complex photonic systems at the University of Twente.

About the Rubicon programme

NWO's Rubicon programme offers brand-new PhDs the opportunity to gain experience at a top-level institute abroad. That can provide an important impetus for the individual’s scientific career.

For more information about Rubicon, please visit the: Rubicon website.

More information about the research

For more information about the research, please contact Jelmer Renema: j.j.renema@utwente.nl.