10 papers
An Operational Resolution of the Third-Particle Paradox
Äaslav Brukner, Esteban Castro-Ruiz, Marius Krumm
We give an operational resolution of the third-particle paradox, relevant in the theory of quantum reference frames. The apparent paradox is that a system which is irrelevant in on…
Schroedinger's Equation at 100: The Wave Picture That Helped and Possibly Hurt
Caslav Brukner
Schroedinger's equation gave early quantum theory a visual language that looked like physics again: a wave evolving by a linear differential equation. This essay argues that the sa…
Circuit locality from relativistic locality in scalar field mediated entanglement
Andrea Di Biagio, Richard Howl, Äaslav Brukner +2
Locality is a central notion in modern physics, but different disciplines understand it in different ways. Quantum field theory focuses on relativistic locality, based on spacetime…
The sum of entanglement and subsystem coherence is invariant under quantum reference frame transformations
Carlo Cepollaro, Ali Akil, PaweÅ CieÅliÅski +2
Recent work on quantum reference frames (QRFs) has demonstrated that superposition and entanglement are properties that change under QRF transformations. Given their utility in qua…
Indefinite causal order and quantum coordinates
Anne-Catherine de la Hamette, Viktoria Kabel, Marios Christodoulou +1
Classically the causal order of two timelike separated events A and B is fixed -- either A before B or B before A. This is no longer true in quantum theory, where it is possible to…
Knot invariants and indefinite causal order
Samuel Fedida, Anne-Catherine de la Hamette, Viktoria Kabel +1
We explore indefinite causal order between events in the context of quasiclassical spacetimes in superposition. We introduce several new quantifiers to measure the degree of indefi…