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It has been shown that any generalized measurement can be decomposed into a sequence of weak measurements corresponding to a stochastic process. However, the weak measurements may require almost arbitrary unitaries, which are unlikely to be…

Quantum Physics · Physics 2019-08-20 Yi-Hsiang Chen , Todd A. Brun

The spin-coherent-state positive-operator-valued-measure (POVM) is a fundamental measurement in quantum science, with applications including tomography, metrology, teleportation, benchmarking, and measurement of Husimi phase space…

Quantum Physics · Physics 2018-10-03 Ezad Shojaee , Christopher S. Jackson , Carlos A. Riofrio , Amir Kalev , Ivan H. Deutsch

We theoretically describe the weak measurement of a two-level system (qubit) and quantify the degree to which such a qubit measurement has a quantum non-demolition (QND) character. The qubit is coupled to a harmonic oscillator which…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Luca Chirolli , Guido Burkard

We present adaptive measurement techniques tailored for variational quantum algorithms on near-term small and noisy devices. In particular, we generalise earlier "learning to measure" strategies in two ways. First, by considering a class of…

The objective of this work is to develop a recursive, discrete time quantum filtering equation for a system that interacts with a probe, on which measurements are performed according to the Positive Operator Valued Measures (POVMs)…

Quantum Physics · Physics 2013-09-10 Ram A. Somaraju , Alain Sarlette , Hugo Thienpont

We report an optical detector with tunable positive operator-valued measures (POVMs). The device is based on a combination of weak-field homodyne techniques and photon-number-resolving detection. The resulting POVMs can be continuously…

We derive a measurement operator corresponding to a quantum nondemolition (QND) measurement of an atomic ensemble. The quantum measurement operator takes the form of a positive operator valued measure (POVM) and is valid for arbitrary…

The informational approach to continuous quantum measurement is derived from POVM formalism for a mesoscopic scattering detector measuring a charge qubit. Quantum Bayesian equations for the qubit density matrix are derived, and cast into…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Andrew N. Jordan , Alexander N. Korotkov

A photodetector may be characterized by various figures of merit such as response time, bandwidth, dark count rate, efficiency, wavelength resolution, and photon-number resolution. On the other hand, quantum theory says that any measurement…

Quantum Physics · Physics 2017-10-04 S. J. van Enk

The positive operator valued measure (POVM) for a photon counting array detector is derived and found to equal photon flux density integrated over pixel area and measurement time. Since photon flux density equals number density multiplied…

Quantum Physics · Physics 2015-05-19 Margaret Hawton

For a quantum measurement process described by a quantum instrument $\mathcal{I}$ and a system observable corresponding to a positive-operator valued measure (POVM) $E ,$ $\mathcal{I}$ is said to conserve the information of $E$ if the joint…

Quantum Physics · Physics 2015-09-30 Yui Kuramochi

A quantum measurement can be described by a set of matrices, one for each possible outcome, which represents the positive operator-valued measure (POVM) of the sensor. Efficient protocols of POVM extraction for arbitrary sensors are…

We show that a one-dimensional discrete time quantum walk can be used to implement a generalized measurement in terms of positive operator value measure (POVM) on a single qubit. More precisely, we show that for a single qubit any set of…

Quantum Physics · Physics 2013-05-22 Pawel Kurzynski , Antoni Wojcik

We present a method for measuring quantum states encoded in the temporal modes of photons. The basis for the multilevel quantum states is defined by the use of modes propagating in a dispersive medium, which is a fiber in this case. The…

Quantum Physics · Physics 2020-11-26 Karolina Sedziak-Kacprowicz , Artur Czerwinski , Piotr Kolenderski

The process of cavity mode quantum state photodetection subject to a nonideal measurement device is under consideration. A set of nonorthogonal probabilistic operator valued measures (POVMs) describing the photodetection process is…

Quantum Physics · Physics 2012-10-18 Alexander Trifanov , George Miroshnichenko

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

In quantum theory general measurements are described by so-called Positive Operator-Valued Measures (POVMs). We show that in $d$-dimensional quantum systems an application of depolarizing noise with constant (independent of $d$) visibility…

Quantum Physics · Physics 2025-01-17 Michał Kotowski , Michał Oszmaniec

We consider the statistical properties of photon detection with imperfect detectors that exhibit dark counts and less than unit efficiency, in the context of tomographic reconstruction. In this context, the detectors are used to implement…

Quantum Physics · Physics 2015-05-13 K. M. R. Audenaert , S. Scheel

We tackle the dynamical description of the quantum measurement process, by explicitly addressing the interaction between the system under investigation with the measurement apparatus, the latter ultimately considered as macroscopic quantum…

Quantum Physics · Physics 2019-07-31 A. De Pasquale , C. Foti , A. Cuccoli , V. Giovannetti , P. Verrucchi

Measurement is the only part of a general quantum system that has yet to be characterized experimentally in a complete manner. Detector tomography provides a procedure for doing just this; an arbitrary measurement device can be fully…

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