The classical limit for quantum mechanical correlation functions

Mario Castagnino

Ayu Ningsih P. A. Sunaryo, Herry Fridolin Lalus, Hartoyo Yudhawardana

A review of the journal entitled 'Classical And Quantum Correlation Functions For A Ring Model' has been carried out which discusses the solutions of classical and quantum correlation functions for the ring model. Classical and quantum correlation functions are derived for systems of non-interacting particles moving in a circle. demonstrated that the decay behavior of the classical expression for the correlation function can be recovered from a strictly periodic quantum mechanical expression by taking the limit ℏ→0, after the appropriate transformation. The aim of this study is to present clearly and in detail how the position correlation function for a system of particles moving in a circle having a certain average energy and written in a form which shows the nature of the transformation. Next, we examine the use of Poisson addition to represent F(z), and how the correlation function becomes identical to the form given by classical statistical mechanics, which exhibits Gaussian decay. The results of this study indicate that the positional correlation function for a system of particles moving in a circle, and having a certain average energy, can be written in a form which shows the nature of the transformation. Then using the Poisson addition formula to represent F(z), the expression is rewritten to enable the limit ℏ→0 to be taken. It was finally found that the correlation function became identical to the form given by classical statistical mechanics, which exhibits a Gaussian decay.

Brian H Buck, C V Sukumar

Classical and quantum correlation functions are derived for a system of non-interacting particles moving on a circle. It is shown that the decaying behaviour of the classical expression for the correlation function can be recovered from the strictly periodic quantum mechanical expression by taking the limit that the Planck's constant goes to zero, after an appropriate transformation.

Anonymous

Salman Habib

We study the classical limit of quantum mechanics as applied to quantum cosmology. Conventional wisdom regards the peaking of the Wigner function of the Universe around a classical trajectory as being a quantum prediction of that trajectory. We show that, with quantum interference correctly taken into account, the hoped for "classical correlation" does not exist. There are, therefore, serious difficulties with the notion that a pure quantum state has a classical limit relevant to the description of our world. Some form of quantum decoherence appears necessary for a strict classical limit to exist. This alternative is briefly discussed.

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