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Related papers: Demystifying weak measurements

200 papers

Weak measurements offer new insights into the behavior of quantum systems. Combined with post-selection, quantum mechanics predicts a range of new experimentally testable phenomena. In this paper I consider weak measurements performed on…

Quantum Physics · Physics 2009-11-13 P. C. W. Davies

Measurement plays a quintessential role in the control of quantum systems. Beyond initialization and readout which pertain to projective measurements, weak measurements in particular, through their back-action on the system, may enable…

Quantum Physics · Physics 2022-06-07 Yunzhao Wang , Kyrylo Snizhko , Alessandro Romito , Yuval Gefen , Kater Murch

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

The weak values and weak measurement formalism were initially limited to pure states, which were later extended to mixed states, leading to intriguing applications in quantum information processing tasks. Weak values are considered to be…

Quantum Physics · Physics 2025-11-04 Rajendra Singh Bhati

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

Weak measurement with a coherent state pointer and in combination with an orthogonal postselection can lead to a surprising amplification effect, and we give a fire-new physical mechanism about the weak measurement in order to understand…

Quantum Physics · Physics 2015-09-03 Gang Li , Ming-Yong Ye , Xiu-Min Lin , He-Shan Song

One of the broadest concepts of measurement in quantum theory is the generalized measurement. Another paradigm of measurement--arising naturally in quantum optics, among other fields--is that of continuous-time measurements, which can be…

Quantum Physics · Physics 2009-11-13 Martin Varbanov , Todd A. Brun

Weak values are quantities accessed through quantum experiments involving weak measurements and post-selection. It has been shown that 'anomalous' weak values (those lying beyond the eigenvalue range of the corresponding operator) defy…

Quantum Physics · Physics 2019-10-23 Ravi Kunjwal , Matteo Lostaglio , Matthew F. Pusey

The correlation function in quantum systems plays a vital role in decoding their properties and gaining insights into physical phenomena. Its interpretation corresponds to the propagation of particle excitations between space-time, similar…

Quantum Physics · Physics 2024-05-14 Yuan Feng , Xi Chen , Yongcheng Ding

Weak measurements performed between quantum state preparation and post-selection result in complex values for self-adjoint operators, corresponding to complex conditional probabilities for the projections on specific eigenstates. In this…

Quantum Physics · Physics 2011-10-14 Holger F. Hofmann

Bipartite quantum entangled systems can exhibit measurement correlations that violate Bell inequalities, revealing the profoundly counter-intuitive nature of the physical universe. These correlations reflect the impossibility of…

Quantum Physics · Physics 2015-02-02 B. L. Higgins , M. S. Palsson , G. Y. Xiang , H. M. Wiseman , G. J. Pryde

The apparent nonunitary evolution in the black hole information paradox and recent work on describing wavefunction collapse via nonunitary nonlinear stochastic operators has motivated us to analyze whether mixed states can be distinguished…

Quantum Physics · Physics 2024-08-23 Igor Prlina

Recent empirical work in the field of 'weak measurements' has yielded novel ways of more directly accessing and exploring the quantum wavefunction. Measuring either position or momentum for a photon in a 'weak' manner yields a wide range of…

Quantum Physics · Physics 2013-06-17 David R Geelan

We extend the idea of weak measurements to the general case, provide a complete treatment and obtain results for both the regime when the pre-selected and post-selected states (PPS) are almost orthogonal and the regime when they are exactly…

Quantum Physics · Physics 2015-03-17 Shengjun Wu , Yang Li

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

Various quantum measurement procedures are analyzed and it is shown that under certain conditions they yield consistently {\em weak values} which might be very different from the eigenvalues, the allowed outcomes according to the standard…

Quantum Physics · Physics 2007-05-23 Lev Vaidman

Quantum mechanics does not permit joint measurements of non-commuting observables. However, it is possible to measure the weak value of a projection operator, followed by the precise measurement of a different property. The results can be…

Quantum Physics · Physics 2015-02-25 Holger F. Hofmann

Postselected weak measurement is a useful protocol for amplifying weak physical effects. However, there has recently been controversy over whether it gives any advantage in precision. While it is now clear that retaining failed…

Quantum Physics · Physics 2015-09-18 Shengshi Pang , Todd A. Brun

Quantum measurement is physically realized through a finite dynamical interaction between a system and a measuring apparatus, giving rise to a continuous transition from weak to strong regimes. While this crossover is well understood under…

In this paper, we present a thought experiment that demonstrates that the equivalence of quantum reduced states and statistical mixed states of ensembles is not merely a simple mathematical formulation in quantum mechanics, but rather…

Quantum Physics · Physics 2025-04-18 Zhihong Zuo