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In this Letter we investigate the concept of quantum work and its measurability from the viewpoint of quantum measurement theory. Very often, quantum work and fluctuation theorems are discussed in the framework of projective two-point…

Quantum Physics · Physics 2022-08-11 Konstantin Beyer , Roope Uola , Kimmo Luoma , Walter T. Strunz

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 correspondence between positive operator valued measures (POVMs) and sets of generalized coherent states. Positive operator valued measures describe quantum observables and, similarly to quantum states, also quantum observables…

Quantum Physics · Physics 2012-06-06 Teiko Heinosaari , Juha-Pekka Pellonpää

Positive Operator Value Measures (POVMs) are the most general class of quantum measurements. We propose a setup in which all possible POVMs of a single photon polarization state (corresponding to all possible sets of two-dimensional Kraus…

Quantum Physics · Physics 2009-11-10 S. E. Ahnert , M. C. Payne

The Wigner Phase Operator (WPO) is identified as an operator valued measure (OVM) and its eigen states are obtained. An operator satisfying the canonical commutation relation with the Wigner phase operator is also constructed and this…

Quantum Physics · Physics 2013-12-24 T. Subeesh , Vivishek Sudhir

In the signal-processing literature, a frame is a mechanism for performing analysis and reconstruction in a Hilbert space. By contrast, in quantum theory, a positive operator-valued measure (POVM) decomposes a Hilbert-space vector for the…

Functional Analysis · Mathematics 2020-04-27 Benjamin Robinson , Bill Moran , Doug Cochran

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

We present a theoretical analysis for the metrology quality of joint weak measurements (JWM), in close comparison with the weak-value-amplification (WVA) technique. We point out that the difference probability function employed in the JWM…

Quantum Physics · Physics 2023-09-26 Lupei Qin , Luting Xu , Xin-Qi Li

"Weak measurements" -- involving a weak unitary interaction between a quantum system and a meter followed by a projective measurement -- are investigated when the system has a non-Hermitian Hamiltonian. We show in particular how the…

Quantum Physics · Physics 2012-12-21 A. Matzkin

We consider joint measurement of two and three unsharp qubit observables through an Arthur-Kelly type joint measurement model for qubits. We investigate the effect of initial state of the detectors on the unsharpness of the measurement as…

Quantum Physics · Physics 2013-06-18 Rajarshi Pal , Sibasish Ghosh

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

It is commonly believed that the most general type of a quantum-mechanical measurement is one described by a positive-operator valued measure (POVM). In the present paper, this statement is proven for any measurements on quantum systems…

Quantum Physics · Physics 2014-02-13 A. V. Nenashev

We present a new method to measure the work $w$ performed on a driven quantum system and to sample its probability distribution $P(w)$. The method is based on a simple fact that remained unnoticed until now: Work on a quantum system can be…

Quantum Physics · Physics 2015-06-22 Augusto J. Roncaglia , Federico Cerisola , Juan Pablo Paz

Self-testing represents the strongest form of certification of a quantum system. Here we investigate theoretically and experimentally the question of self-testing non-projective quantum measurements. That is, how can one certify, from…

Quantum measurements can be incompatible, i.e., they can fail to be jointly measurable. Recently, a weaker notion of joint-measurability, called partial joint-measurability, was proposed by Masini et al. in [Quantum 8, 1574 (2024)]. In this…

Quantum Physics · Physics 2026-05-18 Edwin Peter Lobo , Maria Balanzó-Juandó , Stefano Pironio

Probability measures (quasi probability mass), given in the form of integrals of Wigner function over areas of the underlying phase space, give rise to operator valued probability measures (OVM). General construction methods of OVMs, are…

Quantum Physics · Physics 2015-06-26 Demosthenes Ellinas

We consider measurements, described by a positive-operator-valued measure (POVM), whose outcome probabilities determine an arbitrary pure state of a D-dimensional quantum system. We call such a measurement a pure-state informationally…

Quantum Physics · Physics 2009-11-10 Steven T. Flammia , Andrew Silberfarb , Carlton M. Caves

We show that the joint behaviour of an arbitrary pair of quantum observables can be described by quasi-probabilities, which are extensions of the standard probabilities used for describing the behaviour of a single observable. The physical…

Quantum Physics · Physics 2016-07-22 Jaeha Lee , Izumi Tsutsui

A quantum measurement, often referred to as positive operator-valued measurement (POVM), is a set of positive operators $P_j=P_j^\dag\geq 0$ summing to identity, $\sum_jP_j=\mathbb{1}$. This can be seen as a generalization of a probability…

Quantum Physics · Physics 2024-12-30 Albert Rico , Karol Życzkowski

Similarly to quantum states, also quantum measurements can be "mixed", corresponding to a random choice within an ensemble of measuring apparatuses. Such mixing is equivalent to a sort of hidden variable, which produces a noise of purely…

Quantum Physics · Physics 2007-05-23 Giacomo Mauro D'Ariano , Paoloplacido Lo Presti , Paolo Perinotti