On Interchangeability of Probe–Object Roles in Quantum–Quantum Interaction-Free Measurement

Abstract

In this paper we examine Interaction-free measurement (IFM) where both the probe and the object are quantum particles. We argue that in this case the description of the measurement procedure must by symmetrical with respect to interchange of the roles of probe and object. A thought experiment is being suggested that helps to determine what does and what doesn't happen to the state of the particles in such a setup. It seems that unlike the case of classical object, here the state of both the probe and the object must change. A possible explanation of this might be that the probe and the object form an entangled pair as a result of non-interaction.Keywords interaction-free measurement · measurement theory · entanglement · optical tests of quantum theory · quantum description of interaction of light and matter · two qubit interaction PACS 03.65.Ta 03.67.-a 03.65.Aa 42.50.Ct IntroductionThe quantum measurement problem from the very beginning of quantum mechanics has been causing many discussions and was one of the stumbling blocks for the interpretation of the mathematical formalism of the theory [1]. It will not be an exaggeration to say that the question how the wave-function of the object, that is being measured collapses, never was convincingly answered.

Relating quantum incoherence, entanglement and superluminal signalling

“…Additionally, we would like to mention our previous work [38] where impossibility to distinguish the eigenbasis of preparation of the maximally mixed state (and therefore impossibility of FTL signalling) is used as a restriction on what could possibly happen (or not happen) during the process of interactionfree measurement (IFM) when both the object and the probe are quantum. Result being necessity of creation of entanglement during any process of quantumquantum non-interaction, although from the first sight non-interaction should leave the states of the involved quantum particles unchanged.…”