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This work demonstrates that repeated weak measurements together with post-selection can produce sharp dynamical discontinuities in meter observables, even in minimal quantum systems. The discontinuous behavior is governed by the polar angle…

Quantum Physics · Physics 2026-03-12 Lorena Ballesteros Ferraz

The measurability by means of continuous measurements, of an observable $\A(t_0)$, at an instant, and of a time averaged observable, $\bar \A=1/T\int \A(t')dt'$, is examined for linear and in particular for non-linear quantum mechanical…

Quantum Physics · Physics 2007-05-23 Y. Aharonov , B. Reznik

We propose a scheme that can realize a class of positive-operator-valued measures (POVMs) by performing a sequence of projective measurements on the original system, in the sense that for an arbitrary input state the probability…

Quantum Physics · Physics 2007-05-23 Guoming Wang , Mingsheng Ying

We study measures of quantum information when the space spanned by the set of accessible observables is not closed under products, i.e., we consider systems where an observer may be able to measure the expectation values of two operators,…

High Energy Physics - Theory · Physics 2018-08-15 Sudip Ghosh , Suvrat Raju

The AAV effect is the well-known phenomenon where a weak measurement followed by post-selection leads to a pointer shift proportional to the weak value of the measured observable. The effect is usually derived by considering a perturbative…

Quantum Physics · Physics 2014-06-04 Jeff Z. Salvail

Weak values are traditionally obtained using a weak interaction between the measured system and a pointer state. It has, however, been pointed out that weak coupling can be replaced by a carefully tailored strong interaction. This paper…

Quantum Physics · Physics 2020-06-24 Jan Roik , Karel Lemr , Antonín Černoch , Karol Bartkiewicz

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…

We present a new method to measure the work $w$ performed on a driven quantum system and to sample its probability distribution $P(w)$. The method is based on a simple fact that remained unnoticed until now: Work on a quantum system can be…

Quantum Physics · Physics 2015-06-22 Augusto J. Roncaglia , Federico Cerisola , Juan Pablo Paz

We discuss the recently introduced concept of non-deterministic noiseless linear amplification, demonstrating that such an operation can only be performed perfectly with vanishing probability of success. We show that a weak measurement,…

Quantum Physics · Physics 2009-03-26 David Menzies , Sarah Croke

Observations in quantum weak measurements are determined by complex numbers called weak values. We present a geometrical interpretation of the argument of weak values of general Hermitian observables in $N$-dimensional quantum systems in…

Quantum Physics · Physics 2022-09-14 Lorena Ballesteros Ferraz , Dominique L. Lambert , Yves Caudano

We show that a one-dimensional discrete time quantum walk can be used to implement a generalized measurement in terms of positive operator value measure (POVM) on a single qubit. More precisely, we show that for a single qubit any set of…

Quantum Physics · Physics 2013-05-22 Pawel Kurzynski , Antoni Wojcik

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

Generalized measurement schemes on one part of bipartite states, which would leave the set of all separable states insensitive are explored here to understand quantumness of correlations in a more general perspecitve. This is done by…

Quantum Physics · Physics 2012-01-04 A. R. Usha Devi , A. K. Rajagopal , Sudha

We analyse the nature of the statistics of the work done on or by a quantum many-body system brought out of equilibrium. We show that, for the sudden quench and for an initial state which commutes with the initial Hamiltonian, it is…

We combine traditional pointer-based simultaneous measurements of conjugate observables with the concept of quantum Brownian motion of multipartite systems to phenomenologically model simultaneous measurements of conjugate observables in a…

Quantum Physics · Physics 2014-05-14 Raoul Heese , Matthias Freyberger

We demonstrate the conditional reversal of a weak (partial-collapse) quantum measurement on a photonic qubit. The weak quantum measurement causes a nonunitary transformation of a qubit which is subsequently reversed to the original state…

Quantum Physics · Physics 2015-05-13 Yong-Su Kim , Young-Wook Cho , Young-Sik Ra , Yoon-Ho Kim

The notion of incompatibility of measurements in quantum theory is in stark contrast with the corresponding classical perspective, where all physical observables are jointly measurable. It is of interest to examine if the results of two or…

Quantum Physics · Physics 2015-01-29 H. S. Karthik , A. R. Usha Devi , A. K. Rajagopal

The relationship between the real part of the weak value of the momentum operator at a post selected position is discussed and the meaning of the experimentally determined stream-lines in the Toronto experiment of Kocsis {\em et al} is…

Quantum Physics · Physics 2014-08-26 R. Flack , B. J. Hiley

The concept of intrinsic and operational observables in quantum mechanics is introduced. It is argued that, in any realistic description of a quantum measurement that includes a detecting device, it is possible to construct from the…

Quantum Physics · Physics 2007-05-23 Piotr Kochanski , Krzysztof Wodkiewicz

A limitation on simultaneous measurement of two arbitrary positive operator valued measures is discussed. In general, simultaneous measurement of two noncommutative observables is only approximately possible. Following Werner's formulation,…

Quantum Physics · Physics 2008-12-01 Takayuki Miyadera , Hideki Imai