Chiral quantum walks

Dawei Lu, Jacob D. Biamonte, Jun Li, Hang Li, Tomi H. Johnson, Ville Bergholm, Mauro Faccin, Zoltán Zimborás, Raymond Laflamme, Jonathan Baugh, Seth Lloyd

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Given its importance to many other areas of physics, from condensed-matter physics to thermodynamics, time-reversal symmetry has had relatively little influence on quantum information science. Here we develop a network-based picture of time-reversal theory, classifying Hamiltonians and quantum circuits as time symmetric or not in terms of the elements and geometries of their underlying networks. Many of the typical circuits of quantum information science are found to exhibit time asymmetry. Moreover, we show that time asymmetry in circuits can be controlled using local gates only and can simulate time asymmetry in Hamiltonian evolution. We experimentally implement a fundamental example in which controlled time-reversal asymmetry in a palindromic quantum circuit leads to near-perfect transport. Our results pave the way for using time-symmetry breaking to control coherent transport and imply that time asymmetry represents an omnipresent yet poorly understood effect in quantum information science.

Original languageEnglish (US)
Article number042302
JournalPhysical Review A
Issue number4
StatePublished - Apr 1 2016

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics


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