The physical meaning of weak values and measurements can be completely understood within the framework of a conventional quantum mechanical approach. We should not expect the weak value of an observable $\hat A$ with post-selection $\langle F|$ within the eigenvalue range of $\hat A$ because it is not an expectation value of $\hat A$ .The physical meaning of weak values and measurements can be completely understood within the framework of a conventional quantum mechanical approach. We should not expect the weak value of an observable $\hat A$ with post-selection $\langle F|$ within the eigenvalue range of $\hat A$ because it is not an expectation value of $\hat A$.

Apr 7, 20160 citations

Simple understanding of quantum weak values

Lupei Qin, Wei Feng, Xin-Qi Li

In this work we revisit the important and controversial concept of quantum weak values, aiming to provide a simplified understanding to its associated physics and the origin of anomaly. Taking the Stern-Gerlach setup as a working system, we base our analysis on an exact treatment in terms of quantum Bayesian approach. We also make particular connection with a very recent work, where the anomaly of the weak values was claimed from the pure statistics in association with "disturbance" and "post-selection", rather than the unique quantum nature. Our analysis resolves the related controversies through a clear and quantitative way.In this work we revisit the important and controversial concept of quantum weak values, aiming to provide a simplified understanding to its associated physics and the origin of anomaly. Taking the Stern-Gerlach setup as a working system, we base our analysis on an exact treatment in terms of quantum Bayesian approach. We also make particular connection with a very recent work, where the anomaly of the weak values was claimed from the pure statistics in association with "disturbance" and "post-selection", rather than the unique quantum nature. Our analysis resolves the related controversies through a clear and quantitative way.

arXiv:1505.00595Scientific ReportsFeb 3, 201626 citations

Non-representative Quantum Mechanical Weak Values

B. E. Y. Svensson

arXiv:1501.04469Foundations of PhysicsSep 19, 201515 citations

Role of weak values in strong measurements

F. De Zela

The physical meaning of the quantum weak value still remains a matter of debate. Originally introduced by Aharonov et al. [Phys. Rev. Lett. 60, 1351 (1988).] as another counterintuitive feature of quantum mechanics, it eventually evolved into a practical tool that is widely used. The theoretical framework in which weak values were introduced was given by von Neumann's model of quantum measurements. In this model, a system is submitted to measurement by coupling it to a ``pointer,'' or meter. In the weak-coupling regime, one may perform a low-order Taylor expansion for the evolution operator of the system and meter. This standard approach ties weak values with weak couplings and weak measurements. We report closed-form expressions that can be used to untie weak values from weak measurements. The regime of strong measurements thereby becomes accessible to weak values, without leaving the framework in which the latter were originally introduced. The reported results should also help us to better understand the physical meaning of weak values.The physical meaning of the quantum weak value still remains a matter of debate. Originally introduced by Aharonov et al. [Phys. Rev. Lett. 60, 1351 (1988).] as another counterintuitive feature of quantum mechanics, it eventually evolved into a practical tool that is widely used. The theoretical framework in which weak values were introduced was given by von Neumann's model of quantum measurements. In this model, a system is submitted to measurement by coupling it to a ``pointer,'' or meter. In the weak-coupling regime, one may perform a low-order Taylor expansion for the evolution operator of the system and meter. This standard approach ties weak values with weak couplings and weak measurements. We report closed-form expressions that can be used to untie weak values from weak measurements. The regime of strong measurements thereby becomes accessible to weak values, without leaving the framework in which the latter were originally introduced. The reported results should also help us to better understand the physical meaning of weak values.

Physical Review AApr 4, 202212 citations

On weak value and weak measurement in quantum mechanics

M. Shioden

茨城工業高等専門学校研究彙報Mar 1, 20140 citations

\hat A

with post-selection

\langle F|

within the eigenvalue range of

\hat A

because it is not an expectation value of

\hat A