Project/Area Number  08044097 
Research Category 
GrantinAid for International Scientific Research.

Section  Joint Research . 
Research Field 
素粒子・核・宇宙線

Research Institution  Waseda University 
Principal Investigator 
NAKAZATO Hiromichi Waseda Univ., Dept.Phys., Assoc.Prof., 理工学部, 助教授 (00180266)

CoInvestigator(Kenkyūbuntansha) 
RAUCH Helmut オーストリア国立原子炉研究所, 教授
COSMAI Leona イタリア国立原子核物理学研究機構(INFN)バリ研究所, 専任研究員
CEA Paolo バリ大学, 物理, 講師
PASCAZIO Sav バリ大学, 物理, 講師
OHBA Ichiro Waseda, Univ., Dept.Phys., Prof., 理工学部, 教授 (10063695)
PAOLO Cea Bari univ., Dept.Phys., Lect., 物理, 講師
SAVERIO Pasc バリ大学, 物理, 講師
SAVERIO Pascazio Bari Univ., Dept.Phys., Lect.

Project Fiscal Year 
1996 – 1997

Project Status 
Completed(Fiscal Year 1997)

Budget Amount *help 
¥2,700,000 (Direct Cost : ¥2,700,000)
Fiscal Year 1997 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1996 : ¥1,100,000 (Direct Cost : ¥1,100,000)

Keywords  quantum mechanics / measurement problem / dissipative process / tunneling phenomena / neutron experiments / 量子力学 / 観測問題 / 散逸過程 / トンネル現象 / 中性子実験 
Research Abstract 
The final goal of this project shall be to understand both macroscopic and mesoscopic systems quantum mechanically. We have investigated such topics that are closely connected to some fundamental issues of quantum mechanics with special attention to the physical and mathematical realization of the micromacro transition. Here is a summary of the project. 1. We have proposed a solvable dynamical model for the quantum measurement proces and scrutinized the mechanism of emergence of the Wiener stochastic process in the weakcoupling, macroscopic limit. It is shown explicitly taht the free Hamiltonian of the detecting macroscopic system plays the role of the Wiener process, which implies that the stchasticity in this model is ascribed to a quantum mechanical origin. 2. Temporal evolution of quantum systems has been reinvestigated in general. Furthermore, the time development of a wave packet was directly calculated for a simple quantum system, and for the hydrogen system the exact expression of the transition amplitude between different energy levels was derived. In the latter case, the characteristic time scale in the short time region was evaluated and the oscillatory behavior was found to persist in the survival probability. 3. A neutron spinflip experiment which clarifies the occurrence of the quantum Zeno effect has been proposed and examined experimentally and theoretically. 4. Nelson's version of quantum mechanics has beeb applied to a quantum mechanical particle tunmneling through a potential. The behavior of the particle is numerically simulated and the tunneling time has been estimated. We have also tried to take the possible dissipation effect on such a particle into account in this formalism to obtain more realistic tunneling time. 5. We summarized our research on the decoherence mechanism in the quantum mechanical measurement process in the book, "Decoherence and Quantum Measurements, " (Singapore, 1998).
