arXiv subjects

Ryo Harada

Publications and source records attributed to Ryo Harada.

2 recordsLinked to original sources

arXiv2011

Operational and harmonic-analytic aspects of quasi-probability distributions

Husimi distributions and Wigner distributions are well-known quasi-probability distributions which appear in several contexts. In this paper, we show some remarkable aspects of these distribution functions related to geometric structures of generalized coherent state systems and operational quantum physics, and a scheme of formulating generalized version of quasi-probability distributions. Our scheme gives concrete formulae of quasi-probability distributions in more direct way from the theory of coherent state systems and clarify their operational meanings, especially of Husimi distributions and mutual relation between Husimi distributions and other classes of quasi-probability distributions.

quant-ph↗

arXiv2008

A Unified Scheme of Measurement and Amplification Processes based on Micro-Macro Duality -- Stern-Gerlach experiment as a typical example

A unified scheme for quantum measurement processes is formulated on the basis of Micro-Macro duality as a mathematical expression of the general idea of quantum-classical correspondence. In this formulation, we can naturally accommodate the amplification processes necessary for magnifying quantum state changes at the microscopic end of the probe system into the macroscopically visible motion of the measuring pointer. Its essence is exemplified and examined in the concrete model of the Stern-Gerlach experiment for spin measurement, where the Helgason duality controlling the Radon transform is seen to play essential roles.

math-ph↗