Quantum origin of quantum jumps: Breaking of unitary symmetry induced by information transfer and the transition from quantum to classical

Mar, 2007
4 pages
Published in:
  • Phys.Rev.A 76 (2007) 052110
e-Print:

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Abstract:
Measurements transfer information about a system to the apparatus, and then further on -- to observers and (often inadvertently) to the environment. I show that even imperfect copying essential in such situations necessarily restricts possible unperturbed outcomes to an orthogonal subset of all possible states of the system, thus breaking the unitary symmetry of its Hilbert space implied by the quantum principle of superposition. Preferred outcome states that emerge as a result provide a framework for the ``wavepacket collapse'': They designate terminal points of quantum jumps, and define measured observable by specifying its eigenstates.
Note:
  • For comments see Seth Lloyd, NATURE 450, 1167 (2007)