• Measurement problem in quantum mechanics: Characteristics of an apparatus

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    • Keywords

       

      Measurement; wavefunction collapse; irreversibility; density matrix; macroscopic apparatus

    • Abstract

       

      The problem of measurement in Quantum Mechanics will be briefly reviewed. Since the measurement process involves a macroscopic apparatus, the attention is focussed on the dynamics of a pointer-like variable of the apparatus when it interacts with a quantum system. It is argued that since the measurement process requires an apparent collapse of the wave function in a certain basis, and collapse is an irreversible process, understanding of irreversibility in a quantum macroscopic system is crucial. The chief characteristics of an apparatus that are important in understanding measurement process are (a) its closely spaced energy levels and (b) its interaction with environment. The coupling with the environment drives the density matrix of the apparatus to diagonal form, but to have persistent correlations between system and apparatus states, it seems necessary to have a pointer variable that has a classical limit

    • Author Affiliations

       

      Deepak Kumar1

      1. School of Physical Sciences, Jawaharlal Nehru University, New Delhi - 110 067, India
    • Dates

       
  • Pramana – Journal of Physics | News

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