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We propose a projection measurement onto encoded Bell states with a static network of linear optical elements. By increasing the size of the quantum error correction code, both Bell measurement efficiency and photon-loss tolerance can be…

Quantum Physics · Physics 2016-11-23 Fabian Ewert , Marcel Bergmann , Peter van Loock

The development of new techniques to improve measurements is crucial for all sciences. By employing quantum systems as sensors to probe some physical property of interest allows the application of quantum resources, such as coherent…

Quantum Physics · Physics 2019-05-15 G. H. Aguilar , M. A. de Souza , R. M. Gomes , J. Thompson , M. Gu , L. C. Céleri , S. P. Walborn

We present a quantum state tomography method that enables the reconstruction of \emph{arbitrary} $d-$dimensional quantum states encoded in the discretized transverse momentum of photons, by using \emph{only} $d+1$ experimental settings. To…

Quantum Physics · Physics 2025-06-23 Quimey Pears Stefano , Lorena Rebón , Claudio Iemmi

We discuss several methods for unambiguous state discrimination of N symmetric coherent states using linear optics and photodetectors. One type of measurements is shown to be optimal in the limit of small photon numbers for any N. For the…

Quantum Physics · Physics 2009-11-07 S. J. van Enk

Entangled quantum states are essential ingredients for many quantum technologies, but they must be validated before they are used. As a full characterization is prohibitively resource-intensive, recent work has focused on developing methods…

Measurement-device-independent quantum key distribution (MDI-QKD), leaving the detection procedure to the third partner and thus being immune to all detector side-channel attacks, is very promising for the construction of high-security…

Quantum Physics · Physics 2014-05-02 Xiang-Chun Ma , Shi-Hai Sun , Mu-Sheng Jiang , Ming Gui , Lin-Mei Liang

Quantum state tomography (QST) represents an essential tool for the characterization, verification, and validation (QCVV) of quantum processors. Only for a few idealized scenarios, there are analytic results for the optimal measurement set…

Quantum Physics · Physics 2022-12-27 Violeta N. Ivanova-Rohling , Niklas Rohling , Guido Burkard

We experimentally investigate a strategy to discriminate between quaternary phase-shift keyed coherent states based on single-shot measurements that is compatible with high-bandwidth communications. We extend previous theoretical work in…

Quantum Physics · Physics 2018-03-21 M. T. DiMario , E. Carrasco , R. A. Jackson , F. E. Becerra

Generalised quantum measurements go beyond the textbook concept of a projection onto an orthonormal basis in Hilbert space. They are not only of fundamental relevance but have also an important role in quantum information tasks. However, it…

In the present paper I formulate a framework that accommodates many unambiguous discrimination problems. I show that the prior information about any type of constituent (state, channel, or observable) allows us to reformulate the…

Quantum Physics · Physics 2010-03-15 Michal Sedlák

The dynamics of a quantum system are characterized by three components: quantum state, quantum process, and quantum measurement. The proper measurement of these components is a crucial issue in quantum information processing. Recently,…

Quantum Physics · Physics 2024-03-28 Kazuhisa Ogawa , Takumi Matsuura , Akihisa Tomita

Quantum algorithms designed for realistic quantum many-body systems, such as chemistry and materials, usually require a large number of measurements of the Hamiltonian. Exploiting different ideas, such as {importance sampling,} observable…

Quantum Physics · Physics 2023-01-18 Bujiao Wu , Jinzhao Sun , Qi Huang , Xiao Yuan

Quantum metrology seeks to push the boundaries of measurement precision by harnessing quantum phenomena. Conventional methods often rely on maximally entangled resources, with states that are usually challenging to produce and sustain in…

Quantum Physics · Physics 2026-02-23 Unathi Skosana , Byron Alexander , Changhyoup Lee , Mark Tame

Certification of quantum systems and their properties has become a field of intensive studies. Here, taking advantage of the one-sided device-independent scenario (known also as quantum steering scenario), we propose a self-testing scheme…

Measurement-based heralded entanglement schemes have served as the primary link between physically separated qubits in most quantum information platforms. However, the impossibility of performing a deterministic Bell measurement with linear…

Quantum Physics · Physics 2019-12-03 Leigh S. Martin , K. Birgitta Whaley

Quantum mechanics allows entanglement enhanced measurements to be performed, but loss remains an obstacle in constructing realistic quantum metrology schemes. However, recent work has revealed that entangled coherent states (ECSs) have the…

Quantum Physics · Physics 2015-06-18 P. A. Knott , W. J. Munro , J. A. Dunningham

An optical transmitter irradiates a target region containing a bright thermal-noise bath in which a low-reflectivity object might be embedded. The light received from this region is used to decide whether the object is present or absent.…

We construct a correspondence between quantum states and the observable input-output correlations they are compatible with. The problem is framed as a game involving an experimenter, claiming to be able to prepare some family of states, and…

Quantum Physics · Physics 2019-06-05 Michele Dall'Arno

Quantum detector tomography is a fundamental technique for calibrating quantum devices and performing quantum engineering tasks. In this paper, we design optimal probe states for detector estimation based on the minimum upper bound of the…

Quantum Physics · Physics 2022-01-13 Shuixin Xiao , Yuanlong Wang , Daoyi Dong , Jun Zhang

Any observable with finite eigenvalue spectrum can be measured using a multiport apparatus realizing an appropriate unitary transformation and an array of detector instruments, where each detector operates as an indicator of one possible…

General Physics · Physics 2022-05-06 Michael Zirpel