English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

It was known that a free, nonrelativistic particle in a superposition ofpositive momenta can, in certain cases, bear a negative probability current ---hence termed quantum backflow. Here, it is shown that more variations can bebrought about for a free Dirac particle, particularly when negative-energysolutions are taken into account. Since any Dirac particle can be understood asan antiparticle that acts oppositely (and vice versa), quantum backflow isfound to arise in the superposition (i) of a well-defined momentum butdifferent signs of energies, or more remarkably (ii) of different signs of bothmomenta and energies. Neither of these cases has counterpart in nonrelativisticquantum mechanics. A generalization by using the field-theoretic formalism isalso presented and discussed.

Quantum backflow in solutions to the Dirac equation of the spin-$1/2$ free particle