Mérnöki kvantumrendszerek központja, Matematikai és Fizikai Iskola, Queenslandi Egyetem, QLD 4072 Ausztrália
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Absztrakt
One of the key ways in which quantum mechanics differs from relativity is that it requires a fixed background reference frame for spacetime. In fact, this appears to be one of the main conceptual obstacles to uniting the two theories. Additionally, a combination of the two theories is expected to yield non-classical, or “indefinite”, causal structures. In this paper, we present a background-independent formulation of the process matrix formalism – a form of quantum mechanics that allows for indefinite causal structure – while retaining operationally well-defined measurement statistics. We do this by postulating an arbitrary probability distribution of measurement outcomes across discrete “chunks” of spacetime, which we think of as physical laboratories, and then requiring that this distribution be invariant under any permutation of laboratories. We find (a) that one still obtains nontrivial, indefinite causal structures with background independence, (b) that we lose the idea of local operations in distinct laboratories, but can recover it by encoding a reference frame into the physical states of our system, and (c) that permutation invariance imposes surprising symmetry constraints that, although formally similar to a superselection rule, cannot be interpreted as such.
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► Referenciák
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Idézi
[1] Matheus Capela, Harshit Verma, Fabio Costa, and Lucas Chibebe Céleri, “Indefinite causal order is not always a resource for thermodynamic processes”, arXiv: 2208.03205.
A fenti idézetek innen származnak SAO/NASA HIRDETÉSEK (utolsó sikeres frissítés: 2022-11-28 18:53:22). Előfordulhat, hogy a lista hiányos, mivel nem minden kiadó ad megfelelő és teljes hivatkozási adatokat.
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