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Register a new userCollapses and Avoiding Wave Function Spreading
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We address the impossibility of achieving exact time reversal in a system with many degrees of freedom. This is a particular example of the difficult task of aiming an initial classical state so as to become a specific final state. We also comment on the classical-to-quantum transition in any non-separable closed system of $n geq 2$ degrees of freedom. Even if the system is initially in a well defined WKB, semi-classical state, quantum evolution and, in particular, multiple reflections at classical turning points make it completely quantum mechanical with each particle smeared almost uniformly over all the configuration space. The argument, which is presented in the context of $n$ hard discs, is quite general. Finally, we briefly address more complex quantum systems with many degrees of freedom and ask when can they provide an appropriate environment to the above simpler systems so that quantum spreading is avoided by continuously leaving imprints in the environment. We also discuss the possible connections with the pointer systems that are needed in the quantum-to-classical collapse transitions.
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In this paper we used the Fredholm method in Schroedingers integral equation in the investigation of the scattering effect near the center of it between a stationary quantum wave function and an electrostatic potential. Two potentials are studied one Coulombian and the other Podolsky. The result shows the importance of the proposal of Podolsky to regularize the effect near the scattering center in the quantum wave function. Being that the coulombian potential presents with strong variation in the amplitude of the wave after the scattering. In the case of Podolskys potential, this is corrected by adopting a constant that removes this strong variation.
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