As part of the online Colloquium series organised by the Centre for Quantum Information, Communication and Computing, we will have a talk by Prof. Barry Sanders (University of Calgary) on Friday, 28th January at 9.00 am.

Title:    Observing a changing Hilbert-space inner product

Abstract : In quantum mechanics, physical states are represented by rays in Hilbert space H, which is. a vector space imbued by an inner product ⟨|⟩, whose physical meaning arises as the overlap ⟨ϕ|ψ⟩ for|ψ⟩ a pure state (description of preparation) and ⟨ϕ| a projective measurement. However, current quantum theory does not formally address the consequences of a changing inner product during the interval between preparation and measurement. We establish a theoretical framework for such a
changing inner product, which we show is consistent with standard quantum mechanics. Furthermore, we show that this change is described by a quantum operation, which is tomographically observable, and we elucidate how our result is strongly related to the exploding topic of PT-symmetric quantum mechanics. We explain how to realize experimentally a changing inner product for a qubit in terms of a qutrit protocol with a unitary channel.

Date: Friday, 28th January 2022 Time: 9.00 am IST

Play recording (57 mins)

Recording password: pVtphqd7