Gravitational cat states as a resource for quantum information processing

TL;DR

This work investigates gravitational cat states (gravcats) as a resource for preserving quantum correlations in open quantum systems. By modeling a two-qubit gravcat under thermal, classical stochastic, decaying, and power-law dephasing noises, and by employing estimators for steering, nonlocality, entanglement, and purity, the authors map how correlations degrade or persist and show that gravcats can robustly retain quantum resources, especially under non-Markovian memory effects. They also explore weak measurement protocols to enhance preservation, compare gravitational and electrostatic couplings, and analyze multi-channel and nonuniform-noise scenarios, concluding that gravcats offer a promising platform for quantum information processing and tests of gravity-quantum interfaces. The results highlight the role of system parameters (energy gap, coupling strength, noise characteristics) and memory effects in sustaining quantum correlations, with practical implications for designing gravity-aware quantum technologies and experiments.

Abstract

We investigate how resourceful gravitational cat states are to preserve quantum correlations. In this regard, we explore the dynamics of gravitational cat states under different situations such as thermal, classical stochastic, general decaying, and power-law noisy fields. In particular, the one-way steerability, Bell non-locality, entanglement, and purity in two qubits are our main focus. We also address the weak measurement protocol on the dynamics of quantum correlations and purity of the state. Our results show that the gravitational cat states have a reliable and better capacity to preserve quantum correlations and remain one of the good resources for the deployment of quantum information processing protocols. Additionally, two independent channels are also employed and it is observed that only the weaker coupling regimes are effective in preserving quantum correlations. Notably, in terms of non-Markovian dynamics implication, quantum correlations are found to be longer preserved because of the information feedback phenomenon between the system and environment. Finally, we present a brief analysis to extend our gravitational model to include the electrostatic notion, providing insight into the key differences between the considered configurations.

Figures (16)

• Figure 1: Schematic representation of the gravcats model. Each symmetric double-well potential is located along a distinct axis, while two axes are parallel at a distance $x =\sqrt{{x^{\prime}}^2-L^2}$.
• Figure 2: Four eigenvalues of the Hamiltonian versus $\gamma$ and $\omega$ when (a) $\omega=1$, (b) $\omega=5$, (c) $\gamma =1$, and (d) $\gamma =5$.
• Figure 3: Dynamics of EW for the two-qubit gravcat state prepared in the state $\rho(t, T)$ given in Eq. \ref{['rho-t']} influenced by a classical stochastic field when (a) $\delta=\gamma=\omega=1,~\lambda=0.5$, (b) $\delta=\gamma=1,~\lambda=0.5,~T =0.1$, (c) $\delta=\gamma=\omega=1,~T =0.1$, (d) $\delta=\omega=1,~\lambda=0.5,~T =0.1$, and (e) $\gamma=\omega=1,~ \lambda=0.5,~T =0.1$.
• Figure 4: Dynamics of EW for the two-qubit gravcat state prepared in the state $\rho(t, T)$ given in Eq. \ref{['rho-t']} influenced by a classical decaying field when (a) $\delta=\gamma=\omega=1,~\mu=0.5,~T =0.1$, (b) $\delta=\gamma=\omega=1,~ \chi=0.1,~T =0.1$, (c) $\delta=\gamma=\omega=1,~\chi =0.1,~\mu=0.5$, (d) $\delta=\gamma=1,~\chi =0.1,~\mu=0.5, ~T=0.1$, (e) $\delta=\omega=1,~\chi =0.1,~\mu=0.5,~T=0.1$, and (f) $\gamma=\omega=1,~\chi =0.1,~\mu=0.5,~T=0.1$.
• Figure 5: Dynamics of EW for the two-qubit gravcat state prepared in the state $\rho(t, T)$ given in Eq. \ref{['rho-t']} influenced by PL noise assisted with classical decaying field when (a) $~g_a=g_b=T=\gamma=10^{-1}$, $\omega=\mu=5$, (b) $g_a=g_b=\chi=T=\gamma=10^{-1},~\omega=5$, (c) $g_a=g_b=\chi=\gamma=10^{-1}$, $\mu=\omega=5$, (d) $g_a=g_b=T=\chi=\gamma=10^{-1}$, $\mu=5$, (e) $g_a=g_b=\chi=T=10^{-1}$, $\omega=\mu=5$, and (f) $g_b=\chi=T=\gamma=10^{-1},~\mu=\omega=5$.