Quantum processes which do not use coherence

By Benjamin Yadin, Jiajun Ma, Davide Girolami, Mile Gu, Vlatko Vedral. 2015

169 citations recorded by the source corpus.

A major signature of quantum mechanics beyond classical physics is coherence, the existence of superposition states. The recently developed resource theory of quantum coherence allows the formalisation of incoherent operations -- those operations which cannot create coherence. We identify the set of operations which additionally do not use coherence. These are such that coherence cannot be exploited by a classical observer, who measures incoherent properties of the system, to go beyond classical dynamics. We give a physical interpretation in terms of interferometry and prove a dilation theorem, showing how these operations can always be constructed by interacting the system in an incoherent way with an ancilla. Such a physical justification is not known for the incoherent operations, thus our results lead to a physically well-motivated resource theory of coherence. Next, we investigate the implications for coherence in multipartite systems. We show that quantum correlations can be defined naturally with respect to a fixed basis, providing a link between coherence and quantum discord. We demonstrate the interplay between these two quantities under our studied operations, and suggest implications for the theory of quantum discord by relating the studied operations to those which cannot create discord.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/fca81853a850fad873bf7d13162e08a6e65cbe86

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In Artificial Intelligence

In Atomic and Molecular Physics, and Optics

Citations in the corpus

Quantum resource theories (2018, background): “Yadin et al. (2016) used this latter observation to consider what CPTP maps arise when such unitaries are used in a Stinespring dilation, i.e. Φ(ρ) = ∑ j TrE[(I⊗ Pj)U(ρS ⊗ γE)U†]⊗ |j〉〈j”
Macroscopic quantum states: Measures, fragility, and implementations (2017, background): “…certain aspects of quantum mechanics such as entanglement (Horodecki et al., 2009), athermality (Goold et al., 2016; Gour et al., 2015), asymmetry (Gour and Spekkens, 2008) and coherence (Baumgratz et al., 2014; Marvian and Spekkens, 2016; Yadin et al., 2016) in the framework of resource theories.”