hep-th/9411196
Paper: hep-th/9411196
From: Lev Vaidman <vaidman@ccsg.tau.ac.il>
Date: Sun, 27 Nov 1994 13:02:40 +0200 (IST)
Date (revised): Tue, 29 Nov 1994 19:47:15 +0200 (IST)
Title: PROTECTIVE MEASUREMENTS
Authors: Yakir Aharonov and Lev Vaidman
Comments: 21 pages, 1 figure
Report-no: TAUP 2214-94
Protective measurements yield properties of the quantum state of a single
quantum system without affecting the quantum state. A protective
measurement involves adiabatic coupling to the measuring device together
with a procedure to protect the state from changing. For nondegenerate
energy eigenstates the protection is provided by the system itself. In this
case it is actually possible to measure the Schr\"odinger wave via
measurements on a single system. This fact provides an argument in favor of
associating physical reality with a quantum state of a single system,
challenging the usual ensemble interpretation. We also believe that the
complete description of a quantum system requires a two-state vector
formalism involving (in addition to the usual one)a future quantum state
evolving backwards in time. Protective measurements testing the two-state
vector reality are constructed.
(N.B.: delivery types and potential problems)
refers to ,
cited by