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We give an overview of joint unsharp measurements of non-commuting observables using positive operator valued measures (POVMs). We exemplify the role played by joint measurability of POVMs in entropic uncertainty relation for Alice's pair…

Quantum Physics · Physics 2015-05-19 H. S. Karthik , A. R. Usha Devi , A. K. Rajagopal

Joint measurements of qubit observables have recently been studied in conjunction with quantum information processing tasks such as cloning. Considerations of such joint measurements have until now been restricted to a certain class of…

Quantum Physics · Physics 2008-06-10 Paul Busch , Teiko Heinosaari

We present a single inequality as the necessary and sufficient condition for two unsharp observables of a two-level system to be jointly measurable in a single apparatus and construct explicitly the joint observables. A complementarity…

Quantum Physics · Physics 2008-09-17 Sixia Yu , Naile Liu , Li Li , C. H. Oh

Joint approximate measurement schemes of position and momentum provide us with a means of inferring pieces of complementary information if we allow for the irreducible noise required by quantum theory. One such scheme is given by the…

Quantum Physics · Physics 2014-09-24 Thomas J Bullock , Paul Busch

Heisenberg's uncertainty relations for measurement quantify how well we can jointly measure two complementary observables and have attracted much experimental and theoretical attention recently. Here we provide an exact tradeoff between the…

Quantum Physics · Physics 2014-02-18 Sixia Yu , C. H. Oh

Unsharp measurements are increasingly important for foundational insights in quantum theory and quantum information applications. Here, we report an experimental implementation of unsharp qubit measurements in a sequential communication…

The notion of incompatibility of measurements in quantum theory is in stark contrast with the corresponding classical perspective, where all physical observables are jointly measurable. It is of interest to examine if the results of two or…

Quantum Physics · Physics 2015-01-29 H. S. Karthik , A. R. Usha Devi , A. K. Rajagopal

We study the problem of performing orthogonal qubit measurements simultaneously. Since these measurements are incompatible, one has to accept additional imprecision. An optimal joint measurement is the one with the least possible…

Quantum Physics · Physics 2010-10-12 Teiko Heinosaari , Maria Anastasia Jivulescu , Daniel Reitzner , Mario Ziman

We investigate the measurement uncertainties of a triple of positive operator-valued measures (POVMs) based on statistical distance, and formulate state-independent tight uncertainty inequalities satisfied by the three measurements in terms…

Quantum Physics · Physics 2019-03-13 Hui-Hui Qin , Ting-Gui Zhang , Leonardo Jost , Chang-Pu Sun , Xianqing Li-Jost , Shao-Ming Fei

The fundamental principles of complementarity and uncertainty are shown to be related to the possibility of joint unsharp measurements of pairs of noncommuting quantum observables. A new joint measurement scheme for complementary…

Quantum Physics · Physics 2009-11-07 P. Busch , C. R. Shilladay

Measurements in quantum theory exhibit incompatibility, i.e., they can fail to be jointly measurable. An intuitive way to represent the (in)compatibility relations among a set of measurements is via a hypergraph representing their joint…

Quantum Physics · Physics 2020-11-04 Nikola Andrejic , Ravi Kunjwal

Joint or simultaneous measurements of non-commuting quantum observables are possible at the cost of increased unsharpness or measurement uncertainty. Many different criteria exist for defining what an "optimal" joint measurement is, with…

Unsharp POVM measurements allow a variety of measurement applications which minimally disrupt the state of the quantum system. Experimental schemes are proposed for implementing unsharp measurements on the qubit levels of a trapped ion. The…

Quantum Physics · Physics 2013-05-30 S. K. Choudhary , T. Konrad , H. Uys

Measurement incompatibility is one of the cornerstones of quantum theory. This phenomenon appears in many forms, of which the concept of non-joint measurability has received considerable attention in the recent years. In order to…

Quantum Physics · Physics 2023-04-05 Juha-Pekka Pellonpää , Sébastien Designolle , Roope Uola

The Mach-Zehnder interferometric setup quantitatively characterizing the wave-particle duality implements in fact a joint measurement of two unsharp observables. We present a necessary and sufficient condition for such a pair of unsharp…

Quantum Physics · Physics 2009-05-12 Nai-Le Liu , Li Li , Sixia Yu , Zeng-Bing Chen

Quantum physics constrains the accuracy of joint measurements of incompatible observables. Here we test tight measurement-uncertainty relations using single photons. We implement two independent, idealized uncertainty-estimation methods,…

A fundamental feature of quantum mechanics is that there are observables which can be measured jointly only when some noise is added to them. Their sharp versions are said to be incompatible. In this work we investigate time-continuous…

Quantum Physics · Physics 2024-06-21 Kalle Raikisto , Kimmo Luoma

Three notions of complementarity - operational, probabilistic, and value complementarity - are reanalysed with respect to the question of joint measurements and compared with reference to some examples of canonically conjugate observables.…

Quantum Physics · Physics 2011-01-04 P. Busch , P. J. Lahti

Joint, or simultaneous, measurements of non-commuting observables are possible within quantum mechanics, if one accepts an increase in the variances of the jointly measured observables. In this paper, we discuss joint measurements of a spin…

Quantum Physics · Physics 2009-11-11 Erika Andersson , Stephen M. Barnett , Alain Aspect

For sharp quantum observables the following facts hold: (i) if we have a collection of sharp observables and each pair of them is jointly measurable, then they are jointly measurable all together; (ii) if two sharp observables are jointly…

Quantum Physics · Physics 2008-12-08 Teiko Heinosaari , Daniel Reitzner , Peter Stano
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