Quantum Energy Teleportation under Equilibrium and Nonequilibrium Environments

Sachiko Kitajima, Toshihico Arimitsu, MASASHI OBINATA +1 more

Xiaokun Yan, Kun Zhang, Jin Wang

Quantum energy teleportation (QET), implemented via local operations and classical communication, enables carrier-free energy transfer by exploiting quantum resources. While QET has been extensively studied theoretically and validated experimentally in various quantum platforms, enhancing energy output for mixed initial states, as the system inevitably interacts with environments, remains a significant challenge. In this work, we study QET performance in a two-qubit system coupled to equilibrium or nonequilibrium reservoirs. We derive an analytical expression for the energy output in terms of the system Hamiltonian eigenstates, enabling analysis of energy output for mixed states. Using the Redfield master equation, we systematically examine the effects of qubit detuning, nonequilibrium temperature difference, and nonequilibrium chemical potential difference on the energy output. We find that the energy output for mixed states often follows that of the eigenstate with the highest population, and that nonequilibrium environments can enhance the energy output in certain parameter regimes.

Rachel Gardner, Jean-François S. Van Huele

Xiaokun Yan, Zhihai Wang, Kun Zhang +1 more

Quantum teleportation, a fundamental protocol in quantum information science, enables the transfer of quantum states through entangled particle pairs and classical communication channels. While ideal quantum teleportation requires maximally entangled states as resources, real-world implementations inevitably face environmental noise and decoherence effects. In this work, we investigate quantum teleportation in nonequilibrium environments with different temperatures or chemical potentials. We employ the Bloch-Redfield equation to characterize the nonequilibrium dynamics in both bosonic and fermionic reservoirs. Our analysis reveals that nonequilibrium conditions, namely, the temperature difference and chemical potential difference, can significantly enhance the teleportation fidelity beyond what is achievable in equilibrium scenarios. Notably, under certain nonequilibrium conditions, the fidelities for all input states converge to the same value. We term this behavior the teleportation with a fixed-point fidelity. Importantly, at this fixed point, fidelity can be further enhanced by tuning the nonequilibrium parameters. These findings offer crucial insights for the implementation of quantum communication protocols in realistic environments, demonstrating that nonequilibrium conditions not only improve the fidelity but also present a promising avenue for simplifying practical quantum teleportation schemes.

Zhong‐Xiao Man, Yun‐Jie Xia

Hao Fan, Feng-Lin Wu, Lu Wang +2 more