Project/Area Number  10044096 
Research Category 
GrantinAid for Scientific Research (B).

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  Waseda University 
Principal Investigator 
NAKAZATO Hiromichi Waseda University, School of Science and Engineering, Associate Professor, 理工学部, 助教授 (00180266)

CoInvestigator(Kenkyūbuntansha) 
IMAFUKU Kentaro Waseda Univ., School of Sci. & Eng., Assistant, 理工学部, 助手 (10298169)
OHBA Ichiro Waseda Univ., School of Sci. & Eng., Professor, 理工学部, 教授 (10063695)
RAUCH Helmut オーストリア国立原子炉研究所, 教授
CEA Paolo バリ大学, 物理, 講師
PASCAZIO Sav バリ大学, 物理, 講師

Project Period (FY) 
1998 – 1999

Project Status 
Completed(Fiscal Year 1999)

Budget Amount *help 
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1999 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1998 : ¥1,200,000 (Direct Cost : ¥1,200,000)

Keywords  quantum mechanics / dissipative process / tunneling phenomena / neutron experiments / stochastic process 
Research Abstract 
The final goal of this project shall be to understand the behaviors of macroscopic and/or mesoscopic systems consistently from the view point of micromacro transition and to establish quantum theories for such systems. We have inverstigated several topics that are closely connected to the fundamental issues of quantum mechanics, and here is a summary of the results of the project. 1. We have studied the temporal brhaviors of quantum (unstable) systems to obtain a better understanding of the mechanism of losing the quantum coherence to give exponential decay. 2. A neutronspin experiment, proposed to test the socalled quantum Zeno effect, has been reanalyzed by taking into account of the possible reflection effect of neutron caused at the boundaries of the magnetic field. It has turned ouf that the effect can become so important that the survival probability of the neutron is completely different from the ideal value. 3. The Nelson stochastic quantization method has been used for extracting information about time in quantum systems. In particular, we have tried to estimate the socalled tunneling time, by applying an oscillating external perturbation to the barrier potential. 4. The stochastic resonance, a phenomenum where a noise can enhance the response to a tiny signal, well known in broad area in classical mechanics, is formulated and analyzed quantum mechanically. 5. A quantum nonlinear optical system is proposed to realize a quantum mechanical analogue of the inverted pendulum in classical mechanins. It is shown that the system, which otherwise produces exponentially growing number of two modes of photons through the nonlinear downconversion process, can be stabilized by applying periodically a linear coupling between the two modes.
