Degree distribution in quantum walks on complex networks

Mauro Faccin, Tomi Johnson, Jacob Biamonte, Sabre Kais, Piotr Migdal

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


In this theoretical study, we analyze quantum walks on complex networks, which model network-based processes ranging from quantum computing to biology and even sociology. Specifically, we analytically relate the average long-time probability distribution for the location of a unitary quantum walker to that of a corresponding classical walker. The distribution of the classical walker is proportional to the distribution of degrees, which measures the connectivity of the network nodes and underlies many methods for analyzing classical networks, including website ranking. The quantum distribution becomes exactly equal to the classical distribution when the walk has zero energy, and at higher energies, the difference, the socalled quantumness, is bounded by the energy of the initial state. We give an example for which the quantumness equals a Rényi entropy of the normalized weighted degrees, guiding us to regimes for which the classical degree-dependent result is recovered and others for which quantum effects dominate.

Original languageEnglish (US)
Article number041007
JournalPhysical Review X
Issue number4
StatePublished - 2014

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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