Quantum causal histories in the light of quantum information

Etera R. Livine*, Daniel R. Terno

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)
    9 Downloads (Pure)


    We use techniques of quantum information theory to analyze the quantum causal histories approach to quantum gravity. While it is consistent to introduce closed timelike curves (CTCs), they cannot generically carry independent degrees of freedom. Moreover, if the effective dynamics of the chronology-respecting part of the system is linear, it should be completely decoupled from the CTCs. In the absence of a CTC, not all causal structures admit the introduction of quantum mechanics. It is possible for those and only those causal structures that can be represented as quantum computational networks. Dynamics of the subsystems should not be unitary or even completely positive. However, we show that other commonly made assumptions ensure the complete positivity of the reduced dynamics.

    Original languageEnglish
    Article number084001
    Pages (from-to)1-8
    Number of pages8
    JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
    Issue number8
    Publication statusPublished - 2 Apr 2007

    Bibliographical note

    Copyright 2007 by The American Physical Society. Reprinted from Physical review D.


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