Naslov
Minimum-cost quantum measurements for quantum information

Autori
Wallden, Petros ; Dunjko, Vedran ; Andersson, Erika

Izvornik
Journal of physics. A, Mathematical and theoretical (1751-8113) 47 (2014), 12; 125303-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Foundations of quantum mechanics; measurement theory; Algebraic methods; Quantum computation architectures and implementations; Quantum communication

Sažetak
Knowing about optimal quantum measurements is important for many applications in quantum information and quantum communication. However, deriving optimal quantum measurements is often difficult. We present a collection of results for minimum- cost quantum measurements, and give examples of how they can be used. Among other results, we show that a minimum-cost measurement for a set of given pure states is formally equivalent to a minimum-error measurement for certain mixed states of those same pure states. For pure symmetric states it turns out that for a certain class of cost matrices, the minimum-cost measurement is the square-root measurement. That is, the optimal minimum-cost measurement is in this case the same as the minimum-error measurement. These results are in agreement with Nakahira and Usuda (2012 Phys. Rev. A 86 062305). Finally, we consider sequences of individual uncorrelated systems, and examine when the global minimum-cost measurement is a sequence of optimal local measurements. We consider an example where the global minimum-cost measurement is, perhaps counter-intuitively, not a sequence of local measurements, and discuss how this is related to the Pusey–Barrett–Rudolph argument for the nature of the wave function.

Izvorni jezik
Engleski

Znanstvena područja
Matematika, Fizika, Informacijske i komunikacijske znanosti

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