Quenched entanglement harvesting

TL;DR

This work analyzes entanglement harvesting in a (1+1)-dimensional quench spacetime that models a Dirac-field analogue of the Unruh effect, using derivative-coupled Unruh-DeWitt detectors. By computing the post-quench Wightman function and the detector correlation terms, it demonstrates that harvested concurrence and mutual information resemble those in Rindler spacetime, with a small but detectable enhancement when the quench-induced energy pulse crosses the detectors. The results strengthen the case that entanglement harvesting can be realized in Rodríguez-Laguna et al.'s optical-lattice analogue, highlighting a path toward experimental observation of Unruh-like phenomena in controllable quantum simulators. The study also clarifies how the energy-pulse dynamics imprint on correlations, offering quantitative predictions for future investigations in analogue gravity setups.

Abstract

Ultracold fermionic atoms in an optical lattice, with a sudden position-dependent change (a quench) in the effective dispersion relation, have been proposed by Rodríguez-Laguna et al as an analogue spacetime test of the Unruh effect. We provide new support for this analogue by analysing the entanglement of a scalar field in a (1 + 1)-dimensional continuum spacetime with a similar quench, and the harvesting of this entanglement by a pair of Unruh-DeWitt detectors. We present numerical evidence that the concurrence and mutual information harvested by the detectors are qualitatively similar to those in Rindler spacetime, but they exhibit a small yet noticeable variation when the energy pulse created by the quench crosses the detectors. These findings provide further motivation to implement the experimental proposal of Rodríguez-Laguna et al.

Figures (5)

• Figure 1: Schematic image of the trajectories swept over to calculate their concurrence. The trajectory $X_A$ was kept at fixed $y_{0A}$, while that for $X_B$ was swept from $y_{0B_0}$ (red) to $y_{0B_f}$ (blue). The supports of the switching functions were studied in three separate cases, above (purple), at (orange), and below (green) the lightcone. These supports are shown with bolder lines.
• Figure 2: Concurrence obtained by detectors interacting below the SET pulse, as a function of $\Omega$ and initial position of detector B, $\chi_{B0}$.
• Figure 4: Concurrence obtained by detectors interacting above the SET pulse, as a function of $\Omega$ and initial position of detector B, $\chi_{B0}$.
• Figure 6: Mutual Information obtained by detectors interacting below the SET pulse, as a function of $\Omega$ and initial position of detector B, $\chi_{B0}$.
• Figure 8: Mutual Information obtained by detectors interacting above the SET pulse, as a function of $\Omega$ and initial position of detector B, $\chi_{B0}$.