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Entanglement Entropy as a Probe beyond the Horizon
Konstantinos Boutivas1, Dimitrios Katsinis1, Georgios Pastras1
1National and Kapodistrian University of Athens, Department of Physics, 15784 Zografou, Attiki, Greece.
Physical Review Letters
|August 27, 2025
Summary
The expansion of de Sitter space enhances entanglement entropy through mode squeezing. This effect introduces a logarithmic dependence on system size, relevant for cosmological models.
Area of Science:
- Quantum field theory in curved spacetime
- Cosmology
- Entanglement entropy
Background:
- Entanglement entropy quantifies quantum correlations in a system.
- De Sitter space is a model for an accelerating universe.
- Mode squeezing is a quantum phenomenon affecting field properties.
Purpose of the Study:
- To analytically investigate the impact of cosmic expansion on entanglement entropy.
- To determine how mode squeezing influences entanglement in de Sitter space.
- To establish the relationship between system size and entanglement entropy in cosmological contexts.
Main Methods:
- Analytical calculations of entanglement entropy for a free field.
- Investigating the effects of mode squeezing in de Sitter spacetime.
- Deriving the dependence of entanglement entropy on system size.
Main Results:
- Cosmic expansion, via mode squeezing, enhances entanglement entropy.
- A logarithmic term dependent on system size is identified in the entanglement entropy.
- This size dependence is relevant for spatially finite universes and early inflationary modes.
Conclusions:
- The expansion of de Sitter space fundamentally alters entanglement entropy.
- The identified logarithmic term provides a new observable in cosmological settings.
- This work connects quantum information concepts with large-scale cosmic structures.
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