Description (de)
Workshop »Interplay of quantum information, foundations and gravity«
Mitschnitt einer Veranstaltung des Institute for Quantum Optics and Quantum Information (IQOQI) am Montag, dem 28. Mai 2018 im Theatersaal der Österreichischen Akademie der Wissenschaften
Teil 6: Esteban Castro Ruiz: Entanglement of quantum clocks through gravity
Kamera: Zizhu Wang
Schnitt: Daniel Winkler
Esteban Castro Ruiz arbeitet am Institut für Quantenoptik and Quanteninformation (IQOQI) der Österreichischen Akademie der Wissenschaften.
Abstract: In general relativity, the picture of space-time assigns an ideal clock to each world line. Being ideal, gravitational effects due to these clocks are ignored and the flow of time according to one clock is not affected by the presence of clocks along nearby world lines. However, if time is defined operationally, as a pointer position of a physical clock that obeys the principles of general relativity and quantum mechanics, such a picture is, at most, a convenient fiction. Specifically, we show that the general relativistic mass-energy equivalence implies gravitational interaction between the clocks, whereas the quantum mechanical superposition of energy eigenstates leads to a non fixed metric background. Based only on the assumption that both principles hold in this situation, we show that the clocks necessarily get entangled through time dilation effect, which eventually leads to a loss of coherence of a single clock. Hence, the time as measured by a single clock is not well defined. However, the general relativistic notion of time is recovered in the classical limit of clocks.
INHALT
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Kapitel Titel Position
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1. Vorspann 00:00:00
2. Clocks as physical systems. Time dilation 00:00:08
3. Gravitational interaction of clocks 00:07:25
4. Clocks as coherent states 00:15:02
5. Emergence of classical time dilation 00:20:23
6. Page and Wooters' internal time 00:25:43
7. Three-clock toy model 00:28:22
8. Questions from the audience 00:32:23