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Related papers: Null weak values in multi-level systems

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The standard quantum error correction protocols use projective measurements to extract the error syndromes from the encoded states. We consider the more general scenario of weak measurements, where only partial information about the error…

Quantum Physics · Physics 2019-01-31 Parveen Kumar , Apoorva Patel

We discuss and experimentally demonstrate the role of quantum coherence in a sequence of two measurements collected at different times using weak measurements. For this purpose, we have realized a weak-sequential measurement protocol with…

In this, partly pedagogical review, I attempt to give a self-contained overview of the basis of (non-relativistic) QM measurement theory expressed in density matrix formalism. The focus is on applications to the theory of weak measurement,…

Quantum Physics · Physics 2013-05-27 Bengt E. Y. Svensson

The concept of a \emph{weak value} of a quantum observable was developed in the late 1980s by Aharonov and colleagues to characterize the value of an observable for a quantum system in the time interval between two projective measurements.…

Quantum Physics · Physics 2015-12-17 J. M. Farinholt , A. Ghazarians , J. E. Troupe

We discuss the preceding Comment and conclude that the arguments given there against the relevance of null weak values as representing the absence of a system property are not compelling. We give an example in which the transition matrix…

Quantum Physics · Physics 2018-04-18 Q. Duprey , A. Matzkin

Measurements with variable system-detector interaction strength, ranging from weak to strong, have been recently reported in a number of electronic nanosystems. In several such instances many-body effects play a significant role. Here we…

Mesoscale and Nanoscale Physics · Physics 2016-01-11 Iliya Esin , Alessandro Romito , Ya. M. Blanter , Yuval Gefen

We present a scheme to estimate Gaussian states of one-dimensional continuous variable systems, based on weak (unsharp) quantum measurements. The estimation of a Gaussian state requires us to find position ($q$), momentum ($p$) and their…

Quantum Physics · Physics 2017-04-05 Debmalya Das , Arvind

We investigate four key issues with using a nonzero weak value of the spatial projection operator to infer the past path of an individual quantum particle. First, we note that weak measurements disturb a system, so any approach relying on…

Quantum Physics · Physics 2023-04-25 Jonte R. Hance , John Rarity , James Ladyman

Weak value amplification and other postselection-based metrological protocols can enhance precision while estimating small parameters, outperforming postselection-free protocols. In general, these enhancements are largely constrained…

Quantum Physics · Physics 2023-05-24 Sourav Das , Subhrajit Modak , Manabendra Nath Bera

We consider a continuous measurement of a two-level system (double-dot) by weakly coupled detector (tunnel point contact nearby). While usual treatment leads to the gradual system decoherence due to the measurement, we show that the…

Quantum Physics · Physics 2007-05-23 Alexander N. Korotkov

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

Since weak measurements are known to produce measurement values that can be much larger than the maximal eigenvalues of the measured observable, it is an interesting question how this enhancement of the measurement signal relates to the…

Quantum Physics · Physics 2012-11-21 Holger F. Hofmann

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

We investigate in this work the meaning of weak values through the prism of property ascription in quantum systems. Indeed, the weak measurements framework contains only ingredients of the standard quantum formalism, and as such weak…

Quantum Physics · Physics 2019-03-25 A. Matzkin

Projective measurement is used as a fundamental axiom in quantum mechanics, even though it is discontinuous and cannot predict which measured operator eigenstate will be observed in which experimental run. The probabilistic Born rule gives…

Quantum Physics · Physics 2017-08-09 Apoorva Patel , Parveen Kumar

Weak value amplification (WVA) is a technique in which one can magnify the apparent strength of a measurement signal. Some have claimed that WVA can outperform more conventional measurement schemes in parameter estimation. Nonetheless, a…

Quantum Physics · Physics 2017-02-22 Jérémie Harris , Robert W. Boyd , Jeff S. Lundeen

We analytically and numerically investigate the performance of weak-value amplification (WVA) and related parameter estimation methods in the presence of temporally correlated noise. WVA is a special instance of a general measurement…

Loss of inputs can be detrimental to the security of quantum position verification (QPV) protocols, as it may allow attackers to not answer on all played rounds, but only on those they perform well on. In this work, we study…

Quantum Physics · Physics 2022-08-11 Rene Allerstorfer , Harry Buhrman , Florian Speelman , Philip Verduyn Lunel

A general formalism for joint weak measurements of a pair of complementary observables is given. The standard process of optical three-wave mixing in a nonlinear crystal (such as in parametric down-conversion) is suitable for such tasks. To…

Quantum Physics · Physics 2012-02-27 Shengjun Wu , Marek Żukowski

Photonic quantum metrology harnesses quantum states of light, such as NOON or Twin-Fock states, to measure unknown parameters beyond classical precision limits. Current protocols suffer from two severe limitations that preclude their…