Quantifying quantum invasiveness

Moreira, Saulo V.; Cunha, Marcelo Terra

doi:10.1103/physreva.99.022124

Cited by 20 publications

(22 citation statements)

References 48 publications

(70 reference statements)

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“…Based on our method interpreted as a means to quantify the measurement-induced decoherence, we have additionally demonstrated how to infer the coherence in the trace distance of a qubit state via the performed measurements, providing the necessary information for the success of certain quantum tasks [67,68]. Furthermore, the variance-based form of our criterion enables us to predict the precision to estimate a quantity in settings which consists of noncommuting measurements, which is useful, e.g., when comparing classical and quantum metrology [69]. Thus, we also provide a useful tool to quantify the coherence of measurements for practical purposes.…”

Section: Discussionmentioning

confidence: 98%

Measuring coherence of quantum measurements

Cimini

Gianani

Sbroscia

et al. 2019

Phys. Rev. Research

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The superposition of quantum states lies at the heart of physics and has been recently found to serve as a versatile resource for quantum information protocols, defining the notion of quantum coherence. In this contribution, we report on the implementation of its complementary concept, coherence from quantum measurements. By devising an accessible criterion which holds true in any classical statistical theory, we demonstrate that noncommutative quantum measurements violate this constraint, rendering it possible to perform an operational assessment of the measurement-based quantum coherence. In particular, we verify that polarization measurements of a single photonic qubit, an essential carrier of one unit of quantum information, are already incompatible with classical, i.e., incoherent, models of a measurement apparatus. Thus, we realize a method that enables us to quantitatively certify which quantum measurements follow fundamentally different statistical laws than expected from classical theories and, at the same time, quantify their usefulness within the modern framework of resources for quantum information technology.

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Section: Discussionmentioning

confidence: 98%

Measuring coherence of quantum measurements

Cimini

Gianani

Sbroscia

et al. 2019

Phys. Rev. Research

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“…Of course, the corollary effect of a quantum measurement is the disturbance by the measurement back-action [34,35]. It would be an exciting avenue for future work to include the disturbance into the resource theory of quantum measurement [39]. For example, two quantum measurements could be equally resourceful from the perspective of gaining information, but one might cause more disturbance to the system than the other, rendering it less valuable.…”

Section: Discussionmentioning

confidence: 99%

A Resource Theory of Quantum Measurements

Guff,

McMahon,

Sanders

et al. 2019

Preprint

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Resource theories are broad frameworks that capture how useful objects are in performing specific tasks. In this paper we devise a formal resource theory quantum measurements, focusing on the ability of a measurement to acquire information. The objects of the theory are equivalence classes of positive operator-valued measures (POVMs), and the free transformations are changes to a measurement device that can only deteriorate its ability to report information about a physical system. We show that catalysis and purification, protocols that are possible in other resource theories, are impossible in our resource theory for quantum measurements. Standard measures of information gain are shown to be resource monotones, and the resource theory is applied to the task of quantum state discrimination.

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“…Quantum metrology is concerned with the estimation of such quantitities by exploiting quantum resources in order to improve the precision of the estimation protocol. For example, quantum features such as entanglement [15], squeezing [16], quantum temporal correlations [17,18], and quantum invasiveness [19] can be associated with a significant improvement of sensitivity in metrological protocols. If the global state of a system under inspection is highly sensitive to small variations of a certain parameter, this may be used to increase the precision with which this parameter can be estimated [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

In and out of equilibrium quantum metrology with mean-field quantum criticality

Wald,

Moreira,

Semião

2020

Preprint

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We study the influence that collective transition phenomena have on quantum metrological protocols. The single spherical quantum spin (SQS) serves as stereotypical toy model that allows analytical insights on a mean-field level. First, we focus on equilibrium quantum criticality in the SQS and obtain the quantum Fisher information analytically, which is associated with the minimum lower bound for the precision of estimation of the parameter driving the phase transition. We compare it with the Fisher information for a specific experimental scenario where photoncounting-like measurements are employed. We find how quantum criticality and squeezing are useful resources in the metrological scenario. Second, we obtain the quantum Fisher information for the out of equilibrium transition in the dissipative non-equilibrium steady state (NESS), and investigate how the presence of dissipation affects the parameter estimation. In this scenario, we find that the critical point is shifted by an amount which depends on the dissipation rate. This is used here to design high precision protocols for a whole range of the transition-driving parameter in the ordered phase. In fact, for certain values of the parameter being estimated, dissipation may be used to obtain higher precision when compared to the equilibrium scenario.

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Quantifying quantum invasiveness

Cited by 20 publications

References 48 publications

Measuring coherence of quantum measurements

Measuring coherence of quantum measurements

A Resource Theory of Quantum Measurements

In and out of equilibrium quantum metrology with mean-field quantum criticality

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