APA

Spekkens, R. (2016). Experimental implementation of quantum-coherent mixtures of causal relations. Perimeter Institute. https://pirsa.org/16090056

MLA

Spekkens, Robert. Experimental implementation of quantum-coherent mixtures of causal relations. Perimeter Institute, Sep. 23, 2016, https://pirsa.org/16090056

BibTex

@misc{ pirsa_PIRSA:16090056,
  doi = {10.48660/16090056},
  url = {https://pirsa.org/16090056},
  author = {Spekkens, Robert},
  keywords = {Quantum Foundations},
  language = {en},
  title = {Experimental implementation of quantum-coherent mixtures of causal relations},
  publisher = {Perimeter Institute},
  year = {2016},
  month = {sep},
  note = {PIRSA:16090056 see, \url{https://pirsa.org}}
}
            

Abstract

Understanding the causal influences that hold among the parts of a system is critical both to explaining that system's natural behaviour and to controlling it through targeted interventions. In a quantum world, understanding causal relations is equally important, but the set of possibilities is far richer. The two basic ways in which a pair of time-ordered quantum systems may be causally related are by a cause-effect mechanism or by a common cause acting on both. Here, we show that it is possible to have a coherent mixture of these two possibilities. We realize such a nonclassical causal relation in a quantum optics experiment and derive a set of criteria for witnessing the coherence based on a quantum version of Berkson's paradox. (Joint work with Katja Ried and Kevin Resch)