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Quantum measurements are ubiquitous in quantum information processing tasks, but errors can render their outputs unreliable. Here, we present a scheme that implements a robust projective measurement through measuring code-inspired…

Quantum Physics · Physics 2024-11-11 Yingkai Ouyang

Quantum learning encounters fundamental challenges when estimating non-linear properties, owing to the inherent linearity of quantum mechanics. Although recent advances in single-copy randomized measurement protocols have achieved optimal…

Quantum Physics · Physics 2026-03-30 Zhenyu Du , Yifan Tang , Andreas Elben , Ingo Roth , Jens Eisert , Zhenhuan Liu

We derive entropic uncertainty relations for successive generalized measurements by using general descriptions of quantum measurement within two {distinctive operational} scenarios. In the first scenario, by merging {two successive…

Quantum Physics · Physics 2018-01-04 Kyunghyun Baek , Wonmin Son

Noisy unsharp measurements incorporated in quantum information protocols may hinder performance, reducing the quantum advantage. However, we show that, unlike projective measurements which completely destroy quantum correlations between…

Quantum Physics · Physics 2025-07-01 Sudipta Mondal , Pritam Halder , Amit Kumar Pal , Aditi Sen De

Arrays of individual atoms trapped in optical microtraps with micrometer-scale sizes have emerged as a fundamental, versatile, and powerful platform for quantum sciences and technologies. This platform enables the bottom-up engineering of…

Quantum Gases · Physics 2024-01-10 Shangguo Zhu , Yun Long , Wei Gou , Mingbo Pu , Xiangang Luo

An implementation of the positive operator valued measure (POVM) is given. By using this POVM one can realize the probabilistic teleportation of an unknown two-particle state.

Quantum Physics · Physics 2007-05-23 Feng-Li Yan , Ting Gao , You-Cheng Li

Adaptive measurements were recently shown to significantly improve the performance of quantum state tomography. Utilizing information about the system for the on-line choice of optimal measurements allows to reach the ultimate bounds of…

We propose a method to prepare entangled states and implement quantum computation with atoms in optical cavities. The internal state of the atoms are entangled by a measurement of the phase of light transmitted through the cavity. By…

Quantum Physics · Physics 2009-11-10 Anders S. Sorensen , Klaus Molmer

In this work a quantum imaging setup based on undetected squeezed photons is employed for metrological applications such as sensitive phase measurement and quantum imaging. In spite of the traditional quantum imaging with undetected…

Quantum Physics · Physics 2025-06-10 S. Samimi , Z. Ghasemi , H. Mohammadi

Positive Operator Value Measures (POVMs) are the most general class of quantum measurements. We propose a setup in which all possible POVMs of a single photon polarization state (corresponding to all possible sets of two-dimensional Kraus…

Quantum Physics · Physics 2009-11-10 S. E. Ahnert , M. C. Payne

We measure and characterize anomalous motional decoherence of an atomic ion confined in the lowest quantum levels of a novel rf ion trap that features moveable electrodes. The scaling of decoherence rate with electrode proximity is…

Quantum Physics · Physics 2009-11-13 L. Deslauriers , S. Olmschenk , D. Stick , W. K. Hensinger , J. Sterk , C. Monroe

We study the physical implementation of an optimal tomographic reconstruction scheme for the case of determining the state of a multi-qubit system, where trapped ions are used for defining qubits. The protocol is based on the use of…

Quantum Physics · Physics 2009-11-13 A. B. Klimov , A. Fernández , C. Muñoz , C. Saavedra

The measurement process is taken into account in the dynamics of trapped ions prepared in nonclassical motional states. The induced decoherence is shown to manifest itself both in the inhibition of the internal population dynamics and in a…

Quantum Physics · Physics 2009-10-30 Lorenza Viola , Roberto Onofrio

The objective of this work is to develop a recursive, discrete time quantum filtering equation for a system that interacts with a probe, on which measurements are performed according to the Positive Operator Valued Measures (POVMs)…

Quantum Physics · Physics 2013-09-10 Ram A. Somaraju , Alain Sarlette , Hugo Thienpont

Multiport generalizations of beam splitters are the key component in multipath interferometers, which are important in a range of quantum state engineering and precision measurement schemes. Here we propose a straightforward method for…

Quantum Physics · Physics 2009-04-28 Jessica J. Cooper , David W. Hallwood , Jacob A. Dunningham

Unsharp POVM measurements allow the estimation and tracking of quantum wavefunctions in real-time with minimal disruption of the dynamics. Here we demonstrate that high fidelity state monitoring, and hence quantum control, is possible even…

Quantum Physics · Physics 2015-06-03 T. Konrad , H. Uys

Trapped atomic ions are a proven and powerful tool for the fundamental research of quantum physics. They have emerged in recent years as one of the most promising candidates for several practical technologies including quantum computers,…

Quantum computers are now on the brink of outperforming their classical counterparts. One way to demonstrate the advantage of quantum computation is through quantum random sampling performed on quantum computing devices. However, existing…

Quantum-logic techniques for state preparation, manipulation, and non-destructive interrogation are increasingly being adopted for experiments on single molecular ions confined in traps. The ability to control molecular ions on the quantum…

Quantum Physics · Physics 2022-04-20 Mudit Sinhal , Stefan Willitsch

A method based on optical interferences for measuring optical nonlinearities is presented. In a proof-of-principle experiment, the technique is applied to the experimental determination of the intensity dependence of the photoionization…

Optics · Physics 2013-08-06 F. Billard , P. Béjot , E. Hertz , B. Lavorel , O. Faucher