In a network of interacting quantum systems, achieving fast coherent energy transfer is a challenging task. While quantum systems are susceptible to a wide range of environmental factors, in many physical settings their interactions with quantized vibrations, or phonons, of a supporting structure are the most prevalent. This leads to noise and decoherence in the network, ultimately impacting the energy-transfer process. In this work, we introduce a novel type of coherent energy-transfer mechanism for quantum systems, where phonon interactions are able to actually enhance the energy transfer. Here, a shared phonon interacts with the systems and dynamically adjusts their resonances, providing remarkable directionality combined with quantum speed-up. We call this mechanism phonon-induced dynamic resonance energy transfer and show that it enables long-range coherent energy transport even in highly disordered systems.S Online supplementary data available from stacks.iop.org/njp/16/053018/mmedia is the excitonic polaron energy operator and J jk is the dipolar coupling New J. Phys. 16 (2014) 053018 J Lim et al New J. Phys. 16 (2014) 053018 J Lim et al 4 1 2 ). In an opposite way, when the New J. Phys. 16 (2014) 053018 J Lim et al New J. Phys. 16 (2014) 053018 J Lim et al 7 New J. Phys. 16 (2014) 053018 J Lim et al 8 Directionality can also be induced in a chain of molecules. In figure 5, we consider a threemolecule linear chain with = = J J J 12 23 New J. Phys. 16 (2014) 053018 J Lim et al 9 New J. Phys. 16 (2014) 053018 J Lim et al 10 Figure 5. Directionality of dynamic resonance energy transfer in a chain of molecules. Here we consider a three-molecule linear chain and take = ≡ J J J 12 23 New J. Phys. 16 (2014) 053018 J Lim et al . In the above, the reduced electronic New J. Phys. 16 (2014) 053018 J Lim et al

We show that the influence of the shared phonon bath considered in Hossein-Nejad and Scholes (2010 New J. Phys. 12 065045) on the exciton transfer in a two-molecule system can be reproduced by that of an independent bath model.

In this study, a distinctive feature of quantum computation (QC) is characterized. To this end, a seemingly‐powerful classical computing model, called “stochastic ensemble machine (SEnM),” is considered. The SEnM runs with an ensemble consisting of finite copies of a single probabilistic machine, hence is as powerful as a probabilistic Turing machine (PTM). Then the hypothesis—that is, the SEnM can effectively simulate a general circuit model of QC—is tested by introducing an information‐theoretic inequality, named readout inequality. The inequality is satisfied by the SEnM and imposes a critical condition: if the hypothesis holds, the inequality should be satisfied by the probing model of QC. However, it is shown that the above hypothesis is not generally accepted with the inequality violation; namely, such a simulation necessarily fails, implying that PTM ⊆ QC.