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Related papers: The Trouble with Weak Values

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Weak values are usually associated with weak measurements of an observable on a pre- and post-selected ensemble. We show that more generally, weak values are proportional to the correlation between two pointers in a successive measurement.…

Quantum Physics · Physics 2009-08-03 Lars M. Johansen , Pier A. Mello

The Schr{\"o}dinger inequality is known to underlie the Kennard-Robertson inequality, which is the standard expression of quantum uncertainty for the product of variances of two observables $A$ and $B$, in the sense that the latter is…

Quantum Physics · Physics 2020-08-10 Jaeha Lee , Keita Takeuchi , Kaisei Watanabe , Izumi Tsutsui

Aharonov-Albert-Vaidman's weak values are investigated by a semiclassical method. Examples of the semiclassical calculation that reproduces "anomalous" weak values are shown. Furthermore, a complex extension of Ehrenfest's quantum-classical…

Quantum Physics · Physics 2009-03-19 Atushi Tanaka

A weak measurement performed on a pre- and post-selected quantum system can result in an average value that lies outside of the observable's spectrum. This effect, usually referred to as an "anomalous weak value", is generally believed to…

Quantum Physics · Physics 2019-10-16 Alastair A. Abbott , Ralph Silva , Julian Wechs , Nicolas Brunner , Cyril Branciard

This work will incorporate a few related tools for addressing the conceptual difficulties arising from sewing together classical and quantum mechanics: deterministic operators, weak measurements and post-selection. Weak Measurement, based…

Quantum Physics · Physics 2016-12-21 Eliahu Cohen , Yakir Aharonov

The univariate extreme value theory deals with the convergence in type of powers of elements of sequences of cumulative distribution functions on the real line when the power index gets infinite. In terms of convergence of random variables,…

Probability · Mathematics 2018-10-04 Gane Samb Lo , Modou Ngom , Tchilabola Abozou Kpanzou , Mouminou Diallo

We propose a protocol for a controlled experiment to measure a weak value of the electron's spin in a solid state device. The weak value is obtained by a two step procedure -- weak measurement followed by a strong one (post-selection),…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Alessandro Romito , Yuval Gefen , Yaroslav M. Blanter

Weak values of quantum observables are a powerful tool for investigating quantum phenomena. Some methods for measuring weak values in the laboratory require weak interactions and postselection, while others are deterministic, but require…

Quantum Physics · Physics 2024-10-18 Giulio Chiribella , Kyrylo Simonov , Xuanqiang Zhao

The "anomalous" values of C. Ferrie and J. Combes in Phys. Rev. Lett. 113, 120404 (2014) say nothing about quantum - or even classical - physics. They are not analogues of the weak values that emerge when we describe the quantum world via…

Quantum Physics · Physics 2014-10-03 Yakir Aharonov , Daniel Rohrlich

Modular values are quantities that described by pre- and postselected states of quantum systems like weak values but are different from them: The associated interaction is not necessary to be weak. We discuss an optimal modular-value-based…

Quantum Physics · Physics 2018-11-07 Le Bin Ho , Yasushi Kondo

Some aspects of weak sufficiency of quantum statistics are investigated. In particular, we give necessary and sufficient conditions for the existence of a weakly sufficient statistic for a given family of vector states, investigate the…

Quantum Physics · Physics 2009-11-24 Katarzyna Lubnauer , Andrzej Łuczak , Hanna Podsȩdkowska

We explore the use of weak quantum measurements for single-qubit quantum state tomography processes. Weak measurements are those where the coupling between the qubit and the measurement apparatus is weak; this results in the quantum state…

Quantum Physics · Physics 2017-11-15 Shoumik Chowdhury

Quantum work fluctuation theorems are known to hold when the work is defined as the difference between the outcomes of projective measurements carried out on the Hamiltonian of the system at the initial and the final time instants of the…

Statistical Mechanics · Physics 2023-07-20 Sourabh Lahiri , Subhashish Banerjee , A. M. Jayannavar

One of the most central and controversial element of quantum mechanics is the use of non zero vectors of a Hilbert space (or, more generally, of one dimension subspaces) for representing the state of a quantum system. In particular, the…

Quantum Physics · Physics 2009-11-13 Olivier Brunet

The weak form is a ubiquitous, well-studied, and widely-utilized mathematical tool in modern computational and applied mathematics. In this work we provide a survey of both the history and recent developments for several fields in which the…

Machine Learning · Computer Science 2024-09-12 Daniel A. Messenger , April Tran , Vanja Dukic , David M. Bortz

The average result of a weak measurement of some observable $A$ can, under post-selection of the measured quantum system, exceed the largest eigenvalue of $A$. The nature of weak measurements, as well as the presence of post-selection and…

Quantum Physics · Physics 2014-11-13 Matthew F. Pusey

A quantum state contains the maximal amount of information available for a given quantum system. In this paper we use weak-value expressions to reconstruct quantum states of continuous-variable systems in the quantum optical domain. The…

Quantum Physics · Physics 2012-11-15 Joachim Fischbach , Matthias Freyberger

We refute the widely held belief that the quantum weak value necessarily pertains to weak measurements. To accomplish this, we use the transverse position of a beam as the detector for the conditioned von Neumann measurement of a system…

Quantum Physics · Physics 2013-01-16 J. Dressel , A. N. Jordan

In this letter, we present a new procedure to determine completely the complex modular values of arbitrary observables of pre- and post-selected ensembles, which works experimentally for all measurement strengths and all post-selected…

Quantum Physics · Physics 2016-04-29 Mirko Cormann , Mathilde Remy , Branko Kolaric , Yves Caudano

For continuous weak measurement of qubits, we obtain exact expressions for weak values (WVs) from the post-selection restricted average of measurement outputs, by using both the quantumtrajectory- equation (QTE) and quantum Bayesian…

Quantum Physics · Physics 2016-02-29 Lupei Qin , Pengfei Liang , Xin-Qi Li