The Two Routes to Quantum Mechanics

Alberto G. Rojo, Anthony M. Bloch

Masoumeh Shirichian, Sara Tofighi

The mechanism of transferring and routing information in quantum and classical network are basically different. The basic idea and working principle of quantum networks is based on a unique feature of quantum mechanics known as entanglement. Since entanglement generation rate is a key factor for quantum networks it can be considered as a route metric. In this paper, we propose two different protocols for local entanglement routing in a quantum ring network. In the first protocol, local link entanglement rate is considered as a route metric. However, the routing decision in the second protocol is made based on finding the shortest path between source and destination. It is shown that though local link entanglement rate is decisive criterion for routing in the first algorithm, the second algorithm can reach higher end-to-end entanglement rate.

三男 武谷, 正幸 長崎

Sheng-Tzong Cheng, Chun-Yen Wang, Ming-Hon Tao

In this paper, a quantum routing mechanism is proposed to teleport a quantum state from one quantum device to another wirelessly even though these two devices do not share EPR pairs mutually. This results in the proposed quantum routing mechanism that can be used to construct the quantum wireless networks. In terms of time complexity, the proposed mechanism transports a quantum bit in time almost the same as the quantum teleportation does regardless of the number of hops between the source and destination. From this point of view, the quantum routing mechanism is close to optimal in data transmission time. In addition, in order to realize the wireless communication in the quantum domain, a hierarchical network architecture and its corresponding communication protocol are developed. Based on these network components, a scalable quantum wireless communication can be achieved.

H.H. Rosenbrock

Partha Ghose

Quantum uncertainty emerged from two strikingly different routes to quantum mechanics. Heisenberg's matrix mechanics replaced the classical description of atomic orbits by relations among observable transition quantities and led, in 1927, to the uncertainty relation and its influential measurement-based interpretation. Schrödinger's wave mechanics grew instead from the Bose--Einstein and de Broglie developments and restored a continuous space-time description through matter waves. The two formalisms were soon shown to be closely related, but neither historical route by itself settles the ontological question of whether particles may possess underlying trajectories. After reviewing these developments, including Einstein's criticism of a simple observability doctrine and Mott's wave-mechanical account of straight cloud-chamber tracks, we distinguish precise quantum uncertainty relations from the stronger claim that quantum mechanics excludes definite microscopic histories. We then compare Feynman paths, Bohmian trajectories, Nelson's stochastic mechanics, and finite-speed persistent Goldstein--Kac dynamics. The Kac process has continuous, piecewise differentiable finite-speed paths; its diffusion limit approaches Wiener kinematics, while analytic continuation of its two-sector dynamics is related to Dirac evolution. These examples show that quantum uncertainty relations constrain observable statistics without, by themselves, uniquely determining an underlying path geometry.