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Weak values are typically obtained experimentally by performing weak measurements, which involve weak interactions between the measured system and a probe. However, the determination of weak values does not necessarily require weak…

I propose a scheme for reconstructing the weak value of an observable without the need for weak measurements. The post-selection in weak measurements is replaced by an initial projector measurement. The observable can be measured using any…

Quantum Physics · Physics 2007-06-13 Lars M. Johansen

A simple formula to read out the weak value from the wave function of the measuring device after the postselection with the initial Gaussian profile is proposed. We apply this formula for the weak value to the classical experiment of the…

Quantum Physics · Physics 2016-11-25 Kouji Nakamura

In this work, we consider the systematic error of quantum metrology by weak measurements under decoherence. We derive the systematic error of maximum likelihood estimation in general to the first-order approximation of a small deviation in…

Quantum Physics · Physics 2016-07-22 Shengshi Pang , Jose Raul Gonzalez Alonso , Todd A. Brun , Andrew N. Jordan

We derive schemes to measure the so-called weak values of quantum system observables by coupling of the system to a qubit meter system. We highlight, in particular, the meaning of the imaginary part of the weak values, and show how it can…

Quantum Physics · Physics 2015-05-14 Shengjun Wu , Klaus Mølmer

Weak values are the fundamental values for observables in a pre- and post-selected system. Weak values are typically measured by weak measurement, in which weak values appear in the change of not the pre- and post-selected system but the…

Quantum Physics · Physics 2020-04-21 Kazuhisa Ogawa , Hirokazu Kobayashi , Akihisa Tomita

We study the outcomes in a general measurement with postselection, and derive upper bounds for the pointer readings in weak measurement. Using the idea of weak measurement, we study Hardy's gedanken experiment and show how the "negative…

Quantum Physics · Physics 2015-06-12 Xuanmin Zhu , Qun Wei , Quanhui Liu , Shengjun Wu

A weak measurement consists in coupling a system to a probe in such a way that constructive interference generates a large output. So far, only the average output of the probe and its variance were studied. Here, the characteristic function…

Quantum Physics · Physics 2012-03-07 Antonio Di Lorenzo

We investigate the sequential composition of weak values in the framework of time-symmetric quantum mechanics. Specifically, we consider a forward'' weak measurement from a preselected state $\ket{\psi}$ to a post-selected state…

Quantum Physics · Physics 2025-07-15 Mirco A. Mannucci

A weak value is an effective description of the influence of a pre and post-selected 'principal' system on another 'meter' system to which it is weakly coupled. Weak values can describe anomalously large deflections of the meter, and…

Quantum Physics · Physics 2018-08-13 George C. Knee , G. Andrew D. Briggs

Weak measurement is a novel technique for parameter estimation with higher precision. In this paper we develop a general theory for the parameter estimation based on weak measurement technique with arbitrary postselection. The previous weak…

Quantum Physics · Physics 2016-08-24 Chen Fang , Jing-Zheng Huang , Yang Yu , Qin-Zheng Li , Guihua Zeng

The concept of a modular value of an observable of a pre- and post-selected quantum system is introduced. It is similar in form and in some cases has a close connection to the weak value of an observable, but instead of describing an…

Quantum Physics · Physics 2011-05-17 Yaron Kedem , Lev Vaidman

The weak value of an observable is experimentally accessible by weak measurements as theoretically analyzed by Aharonov et al. and recently experimentally demonstrated. We introduce a weak operator associated with the weak values and give a…

Quantum Physics · Physics 2010-06-11 Yutaka Shikano , Akio Hosoya

We quantify the disturbance of a quantum state undergoing a sequence of observations, and particularly focus on a weak measurement followed by post-selection and compare these results to the projective counterpart. Taking into account the…

Quantum Physics · Physics 2021-01-04 Philipp Stammer

The application of postselection to a weak quantum measurement leads to the phenomenon of weak values. Expressed in units of the measurement strength, the displacement of a quantum coherent measuring device is ordinarily bounded by the…

Quantum Physics · Physics 2014-03-10 George C. Knee , Erik M. Gauger

We investigate the impact of dissipation on weak measurements. While weak measurements have been successful in signal amplification, dissipation can compromise their usefulness. More precisely, we show that in systems with non-degenerate…

Quantum Physics · Physics 2024-05-13 Lorena Ballesteros Ferraz , John Martin , Yves Caudano

Weak measurements are a unique tool for accessing information about weakly interacting quantum systems with minimal back action. Joint weak measurements of single-particle operators with pointer states characterized by a two-dimensional…

Quantum Physics · Physics 2012-11-13 G. Puentes , N. Hermosa , J. P. Torres

Historically, weak values have been associated with weak measurements performed on quantum systems. Over the past two decades, a series of works have shown that weak values can be determined via measurements of arbitrary strength. One such…

Quantum Physics · Physics 2023-09-06 David R. A. Ruelas Paredes , Mariano Uria , Eduardo Massoni , Francisco De Zela

It is argued that a weak value of an observable is a robust property of a single pre- and post-selected quantum system rather than a statistical property. During an infinitesimal time a system with a given weak value affects other systems…

To describe the pre- and post-selected quantum ensembles, a complex quantity called the weak value of an operator is used. The weak value is highly controversial due to the fact that it is not bounded by the possible eigenvalues of the…

Quantum Physics · Physics 2023-03-20 Aiham M. Rostom