Transport in the quantum world

Alex Kamenev

Oliver Mülken, Volker Pernice, A. Blumen

We consider the quantum mechanical transport of (coherent) excitons on small-world networks (SWNs). The SWNs are built from a one-dimensional ring of N nodes by randomly introducing B additional bonds between them. The exciton dynamics is modeled by continuous-time quantum walks, and we evaluate numerically the ensemble-averaged transition probability to reach any node of the network from the initially excited one. For sufficiently large B we find that the quantum mechanical transport through the SWNs is, first, very fast, given that the limiting value of the transition probability is reached very quickly, and second, that the transport does not lead to equipartition, given that on average the exciton is most likely to be found at the initial node.

changzheng zhou, ZIQING zhou

This paper constructs a new framework for the many-worlds interpretation thatintegrates symplectic geometry, quantum information geometry, and optimal transport theory. The central thesis is that world branches are not static splits in Hilbertspace, but rather a Lagrangian submanifold fibration process on a symplectic manifold driven by decoherence. We prove that the Born rule for the squared magnitudeof wave function amplitudes arises from a strict duality between symplectic volume conservation and the measure transformation induced by the quantum Fishermetric. An optimal transport cost functional between worlds is introduced as adynamical criterion for branch reality: a corresponding branch can support a stable information-recording structure if and only if the transport cost is lower thana critical threshold determined by the spectral gap. This framework transformsthe traditional measure problem of the many-worlds interpretation into a computable geometric optimization problem and achieves an explicit construction ofself-consistent observer conditions within the string theory landscape. The theorypredicts observable geometric phase effects in superconducting quantum simulators,and on cosmological scales, it corresponds to non-Gaussian deviations in primordialdensity perturbations. This work provides a complete mathematical implementation for the many-worlds interpretation, from ontology to phenomenology.

B. K. Ridley FRS

David K. Ferry

Amena Khatun, Harish J. Vallury, Maryam Rajabi +5 more

This work provides an updated report on the progress and prospects of quantum computing for advancing transport modeling. Despite recent developments in classical methods, their use in computationally intensive transport tasks such as traffic assignment, traffic signal control, logistics, and pedestrian modeling remains limited due to the combinatorial complexity and uncertainty associated with the real-world transport scenarios. Quantum optimization algorithms offer the potential for addressing transport problems, although most studies still remain at the proof-of-concept stage. In this work, we highlight key challenges in traffic and logistics optimization and investigate how quantum optimization tools could lead to novel and efficient solutions. Our perspective offers a clear and concise timeline for the development of quantum optimization techniques and their practical implementation aspects by highlighting key hardware/software challenges and proposed solutions. We also discuss the barriers to adoption within transport contexts and possible pathways to overcome current limitations to the application of quantum optimization techniques in real-world transport systems. Finally, we provide our perspective for the applications of quantum computing in addressing challenges pertaining to large crowd management and transport optimization during the Olympics and Paralympics 2032 Games which may coincide with the development of a large-scale quantum computer.