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Three recent results on weak measurements are presented. They are: i) repeated measurements on a single copy can not provide any information on it and further, that in the limit of very large such measurements, weak measurements have…

Quantum Physics · Physics 2015-09-17 N. D. Hari Dass

We address the issue of how to properly treat, and in a more general setting, the concept of a weak value of a weak measurement in quantum mechanics. We show that for this purpose, one must take in account the effects of the measuring…

Quantum Physics · Physics 2009-07-24 A. C. Lobo , C. A. Ribeiro

Weak values arise in quantum theory when the result of a weak measurement is conditioned on a subsequent strong measurement. The majority of the trials are discarded, leaving only very few successful events. Intriguingly those can display a…

Quantum Physics · Physics 2016-05-19 George C. Knee , Joshua Combes , Christopher Ferrie , Erik M. Gauger

It has been proposed by Cook (Phys. Scr. T 21, 49 (1988)) to use a short probe laser pulse for state measurements of two-level systems. In previous work we have investigated to what extent this proposal fulfills the projection postulate if…

atom-ph · Physics 2015-06-24 Almut Beige , Gerhard C. Hegerfeldt

Data assimilation performance can be significantly impacted by biased noise in observations, altering the signal magnitude and introducing fast oscillations or discontinuities when the system lacks smoothness. To mitigate these issues, this…

Numerical Analysis · Mathematics 2024-11-05 Felipe Galarce , Joaquin Mura , Alfonso Caiazzo

In a quantum-noise limited system, weak-value amplification using post-selection normally does not produce more sensitive measurements than standard methods for ideal detectors: the increased weak value is compensated by the reduced power…

Quantum Physics · Physics 2021-06-09 Courtney Krafczyk , Andrew N. Jordan , Michael E. Goggin , Paul G. Kwiat

Weak measurement is a novel quantum measurement scheme, which is usually characterized by the weak value formalism. To guarantee the validity of the weak value formalism, the fidelity between the pre-selection and the post-selection should…

Quantum Physics · Physics 2015-06-05 Shengshi Pang , Shengjun Wu , Zeng-Bing Chen

The notion of weak measurement provides a formalism for extracting information from a quantum system in the limit of vanishing disturbance to its state. Here we extend this formalism to the measurement of sequences of observables. When…

Quantum Physics · Physics 2009-11-13 Graeme Mitchison , Richard Jozsa , Sandu Popescu

A Bose-Einstein condensate may be used to make precise measurements of weak forces, utilizing the macroscopic occupation of a single quantum state. We present a scheme which uses a condensate in a double well potential to do this. The…

Condensed Matter · Physics 2009-10-31 J. F. Corney , G. J. Milburn , Weiping Zhang

The task of state discrimination for a set of mutually orthogonal pure states is trivial if one has access to the corresponding sharp (projection-valued) measurement, but what if we are restricted to an unsharp measurement? Given that any…

Quantum Physics · Physics 2021-03-03 Tom Bullock , Teiko Heinosaari

We investigate generalized measurements, based on positive-operator-valued measures, and von Neumann measurements for the unambiguous discrimination of two mixed quantum states that occur with given prior probabilities. In particular, we…

Quantum Physics · Physics 2009-11-11 Ulrike Herzog , Janos A. Bergou

The viability of quantum communication schemes rely on sending quantum states of light over long distances. However, transmission loss can degrade the signal strength, adding noise. Heralded noiseless amplification of a quantum signal can…

Quantum Physics · Physics 2016-10-20 Joseph Ho , Allen Boston , Matthew Palsson , Geoff Pryde

In the Aharonov-Albert-Vaidman (AAV) weak measurement, it is assumed that the measuring device or the pointer is in a quantum mechanical pure state. In reality, however, it is often not the case. In this paper, we generalize the AAV weak…

Quantum Physics · Physics 2010-02-25 Young-Wook Cho , Hyang-Tag Lim , Young-Sik Ra , Yoon-Ho Kim

Noise is an important factor that influences the reliability of information acquisition, transmission, processing, and storage. In order to suppress the inevitable noise effects, a fault-tolerant information processing approach via quantum…

Quantum Physics · Physics 2026-03-27 Qi Song , Hongjing Li , Chengxi Yu , Jingzheng Huang , Ding Wang , Peng Huang , Guihua Zeng

In this paper, we propose a method to discriminate two extremely similar quantum states via a weak measurement. For the two states with equal prior probabilities, the optimum discrimination probability given by Ivanovic-Dieks-Peres limit…

Quantum Physics · Physics 2013-02-26 Chang Qiao , Shengjun Wu , Zeng-Bing Chen

We introduce a reliable compressive procedure to uniquely characterize any given low-rank quantum measurement using a minimal set of probe states that is based solely on data collected from the unknown measurement itself. The procedure is…

Quantum Physics · Physics 2020-11-03 I. Gianani , Y. S. Teo , V. Cimini , H. Jeong , G. Leuchs , M. Barbieri , L. L. Sanchez-Soto

The emergence of realistic properties is a key problem in understanding the quantum-to-classical transition. In this respect, measurements represent a way to interface quantum systems with the macroscopic world: these can be driven in the…

The notion of weak measurement in quantum mechanics has gained a significant and wide interest in realizing apparently counterintuitive quantum effects. In recent times, several theoretical and experimental works have been reported for…

Quantum Physics · Physics 2017-11-21 Asmita Kumari , A. K. Pan , P. K. Panigrahi

This paper starts with a brief review of the topic of strong and weak pre- and post-selected (PPS) quantum measurements, as well as weak values, and afterwards presents original work. In particular, we develop a nonperturbative theory of…

Quantum Physics · Physics 2012-10-16 Abraham G. Kofman , Sahel Ashhab , Franco Nori

We report an experimental investigation of the role of measurement in quantum metrology when the states of the probes are mixed. In particular, we investigated optimized local measurements and general global projective measurements,…

Quantum Physics · Physics 2021-02-22 R. S. Piera , S. P. Walborn , G. H. Aguilar