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Large weak values have been used to amplify the sensitivity of a linear response signal for detecting changes in a small parameter, which has also enabled a simple method for precise parameter estimation. However, producing a large weak…

Quantum Physics · Physics 2014-07-23 Shengshi Pang , Justin Dressel , Todd A. Brun

Postselection is an operation that allows the selection of specific measurement outcomes. It serves as a powerful theoretical tool for enhancing the performance of existing quantum algorithms. Despite recent developments such as time…

General Physics · Physics 2024-09-09 Alex Linden , Betül Gül

Weak values and measurements have been proposed as means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur…

Quantum Physics · Physics 2015-06-02 Lijian Zhang , Animesh Datta , Ian A. Walmsley

The ability to post-select the outcomes of an experiment is a useful theoretical concept and experimental tool. In the context of weak measurements post-selection can lead to surprising results such as complex weak values outside the range…

Quantum Physics · Physics 2014-06-09 Dawei Lu , Aharon Brodutch , Jun Li , Hang Li , Raymond Laflamme

It is well-known that a quantum measurement can enhance the transition probability between two quantum states. Such a measurement operates after preparation of the initial state and before postselecting for the final state. Here we analyze…

Quantum Physics · Physics 2010-08-20 Tobias Fritz

Postselected weak measurement has aroused broad interest for its distinctive ability to amplify small physical quantities. However, the low postselection efficiency to obtain a large weak value has been a big obstacle to its application in…

Quantum Physics · Physics 2015-08-14 Shengshi Pang , Todd A. Brun

Quantum mechanics gives a new breakthrough to the field of parameter estimation. In the realm of quantum metrology, the precision of parameter estimation is limited by the quantum Fisher information. We introduce the measures of partial…

Quantum Physics · Physics 2024-11-14 Dong-Ping Xuan , Zhong-Xi Shen , Wen Zhou , Hua Nan , Shao-Ming Fei , Zhi-Xi Wang

We investigate the potential of weak measurement and post-selection to enhance measurement sensitivity when the initial probe state is mixed. In our framework, the mixedness of the probe's density operator is controlled by temperature. We…

Quantum Physics · Physics 2025-09-05 Lorena Ballesteros Ferraz , Alexandre Matzkin , Alok Kumar Pan

The ability of quantum states to be in superposition is one of the key features that sets them apart from the classical world. This `coherence' is rigorously quantified by resource theories, which aim to understand how such properties may…

Quantum Physics · Physics 2024-07-08 Ruvi Lecamwasam , Syed M Assad , Joseph J Hope , Ping Koy Lam , Jayne Thompson , Mile Gu

We study quantum measurement with preselection and postselection, and derive the precise expressions of the measurement results without any restriction on the coupling strength between the system and the measuring device. For a qubit…

Quantum Physics · Physics 2011-11-18 Xuanmin Zhu , Yuxiang Zhang , Shengshi Pang , Chang Qiao , Quanhui Liu , Shengjun Wu

Weak-value amplification employs postselection to enhance the measurement of small parameters of interest. The amplification comes at the expense of reduced success probability, hindering the utility of this technique as a tool for…

Quantum Physics · Physics 2020-12-29 Muthumanimaran Vetrivelan , Sai Vinjanampathy

The indeterminism of quantum mechanics generally permits the independent specification of both an initial and a final condition on the state. Quantum pre-and-post-selection of states opens up a new, experimentally testable, sector of…

Quantum Physics · Physics 2015-06-17 Paul Davies

The reconstruction of quantum states from a sufficient set of experimental data can be achieved with arbitrarily weak measurement interactions. Since such weak measurements have negligible back-action, the quantum state reconstruction is…

Quantum Physics · Physics 2010-03-16 Holger F. Hofmann

In the framework of quantum thermodynamics preparing a quantum system in a general state requires the consumption of two distinct resources, namely, work and coherence. It has been shown that the work cost of preparing a quantum state is…

Quantum Physics · Physics 2022-11-30 Iman Marvian

We introduce a procedure based on quantum expectation values of measurement observables to characterize quantum coherence. Our measure allows one to quantify coherence without having to perform tomography of the quantum state, and can be…

Learning properties of quantum states and channels is known to benefit from resources such as entangled operations, auxiliary qubits, and adaptivity, whereas the resource structure of measurement learning, namely, learning properties of…

Quantum Physics · Physics 2026-02-26 Zhenhuan Liu , Qi Ye , Zhenyu Cai , Jens Eisert

Weak measurements may result in extra quantity of quantumness of correlations compared with standard projective measurement on a bipartite quantum state. We show that the quantumness of correlations by weak measurements can be consumed for…

Quantum Physics · Physics 2014-03-18 Lin-Ping Huai , Bo Li , Shi-Xian Qu , Heng Fan

Quantum measurement is a fundamental yet experimentally challenging ingredient of quantum information processing. Many recent studies on quantum dynamics focus on expectation values of nonlinear observables; however, their experimental…

Quantum Physics · Physics 2025-04-02 Hong-Yi Wang

Quantum metrology concerns improving the estimation of an unknown parameter using an optimal measurement scheme on the quantum system. More the optimality of the measurement, the better will be the improvement in sensing the value of the…

Quantum Physics · Physics 2025-07-30 H. S. Karthik

We show that in presence of a local and uncorrelated dephasing noise, quantum advantage can be obtained in the Fisher information-based lower bound of the minimum uncertainty in estimating parameters of the system Hamiltonian. The quantum…

Quantum Physics · Physics 2024-05-27 Aparajita Bhattacharyya , Ahana Ghoshal , Ujjwal Sen