Quantum Transport

Dong Xie, An Min Wang

In this paper, we report on a detailed study of how decoherence assists quantum transport in a dimer system. By carrying out analytical and numerical computations, we find that the decoherence induced by a Markovian (memoryless) environment only assists the maximum probability of quantum transport in the dimer system to 50% not close to the unity, and the decoherence induced by a non-Markovian environment with perfect memory (infinite memory time) can improve the maximum probability of quantum transport to unity. The combination of non-Markovian decoherence and Markovian decoherence assist the quantum transport more effectively. Comparing the classical environment with the quantum environment, we obtain that the classical non-Markovian environment cannot assist the maximum probability of quantum transport close to unity. In addition, enlarging the quantum environment can improve the maximum probability of quantum transport.

ROSSELLA BRUNETTI, Carlo Jacoboni

Christine Maier, Tiff Brydges, Petar Jurcevic +6 more

The way in which energy is transported through an interacting system governs fundamental properties in nature such as thermal and electric conductivity or phase changes. Remarkably, environmental noise can enhance the transport, an effect known as environment-assisted quantum transport (ENAQT). In this Letter, we study ENAQT in a network of coupled spins subject to engineered static disorder and temporally varying dephasing noise. The interacting spin network is realized in a chain of trapped atomic ions, and energy transport is represented by the transfer of electronic excitation between ions. With increasing noise strength, we observe a crossover from coherent dynamics and Anderson localization to ENAQT and finally a suppression of transport due to the quantum Zeno effect. We find that in the regime where ENAQT is most effective, the transport is mainly diffusive, displaying coherences only at very short times. Further, we show that dephasing characterized by non-Markovian noise can maintain coherences longer than white noise dephasing, with a strong influence of the spectral structure on the transport efficiency. Our approach represents a controlled and scalable way to investigate quantum transport in many-body networks under static disorder and dynamic noise.

Fausto Rossi, ROSSELLA BRUNETTI, Carlo Jacoboni

Grégoire Allaire, Anton Arnold, Pierre Degond +1 more

Byoung Seung HAM

A method of quantum transport between quantum nodes using stationary lights is presented. The quantum transport of a single photon or a quantum state from one node to another is performed by a slow light phenomenon, where the transport time and path between nodes are classically determined. With both no-mirror-cavity characteristics of the stationary light and propagation velocity control of the slow light, the quantum transport has potential applications in quantum information sciences such as type-II quantum computing and quantum communications.