Quantum Information in Relativity: Measurements and Causality
Can two distant detectors signal to each other, even when they are outside each other’s lightcones? Typical detector systems, that are not explicitly embedded in a relativistic spacetime, are not guaranteed to comply with the requirements of relativity theory. In this talk, we will analyse potential violations of causality in Unruh DeWitt-type detector models in relativistic quantum information. These models involve non-relativistic quantum-mechanical detector systems that are locally coupled to a relativistic quantum field. First, we will demonstrate the relation between faster-than-light signaling and the causal factorization of the dynamics for multiple detector-field interactions. Then, we will show in what way spatially extended non-relativistic detector models predict superluminal propagation of the field's initial conditions. We will apply these considerations to define the regime of validity of typical detector models in quantum field theory. Finally, we will argue that a notion of local quantum measurement that is consistent with relativity is essential for the reliable description of quantum information processing in relativistic spacetimes.
This talk will be mostly based on Phys. Rev. D 103, 085002 (2021), arXiv: 2102.03408.
Join the seminar on Zoom!
Meeting link: https://uwaterloo.zoom.us/j/92251599668?pwd=emZmYXUwTDQ5NGhVMWZEN1BUeXVXZz09
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