English
Related papers

Related papers: Characterizing Bell state analyzer using weak cohe…

200 papers

Many quantum information protocols require a Bell-state measurement of entangled systems. Most optical Bell-state measurements utilize two-photon interference at a beam splitter. By creating polarization-entangled photons with spontaneous…

Quantum Physics · Physics 2009-11-07 S. P. Walborn , W. A. T. Nogueira , S. Pádua , C. H. Monken

We prove the security of the Bennett-Brassard (BB84) quantum key distribution protocol in the case where the key information is encoded in the relative phase of a coherent-state reference pulse and a weak coherent-state signal pulse, as in…

Quantum Physics · Physics 2008-02-27 Hoi-Kwong Lo , John Preskill

The discrimination of coherent states is a key task in optical communication and quantum key distribution protocols. In this work, we use a photon-number-resolving detector, the transition-edge sensor, to discriminate binary-phase-shifted…

Quantum Physics · Physics 2021-05-18 G. S. Thekkadath , S. Sempere-Llagostera , B. A. Bell , R. B. Patel , M. S. Kim , I. A. Walmsley

Single-photon coherent optics represents a fundamental importance for the investigation of quantum light-matter interactions. While most work has considered the interaction in the steady-state regime, here we demonstrate that a…

Quantum Physics · Physics 2015-06-17 Shushan Petrosyan , Yuri Malakyan

Kinetic models are essential for describing how molecules interact in a variety of biochemical processes. The estimation of a model's kinetic parameters by experiment enables researchers to understand how pathogens, such as viruses,…

Quantum Physics · Physics 2022-03-02 K. T. Mpofu , C. Lee , G. E. M. Maguire , H. G. Kruger , M. S. Tame

The question of the discrimination of the Bell states of two qudits (i.e., d-dimensional quantum systems) by means of passive linear optical elements and conditional measurements is discussed. A qudit is supposed to be represented by d…

Quantum Physics · Physics 2009-11-07 Miloslav Dusek

It is generally assumed that on-off detectors with single-photon sensitivity cannot distinguish coherent states from phase-mixed coherent states without some form of quadrature-based tomography. Here, we show that it is theoretically…

Quantum Physics · Physics 2016-03-22 Samuel R. Hedemann

We show that measuring pairs of qubits in the Bell basis can be used to obtain a simple quantum algorithm for efficiently identifying an unknown stabilizer state of n qubits. The algorithm uses O(n) copies of the input state and fails with…

Quantum Physics · Physics 2017-07-27 Ashley Montanaro

Quantum networking protocols, including quantum teleportation and entanglement swapping, use linear-optical Bell state measurements for heralding the distribution and transfer of quantum information. However, a linear-optical Bell state…

Quantum Physics · Physics 2025-04-23 Joshua Akin , Yunlei Zhao , Paul G. Kwiat , Elizabeth A. Goldschmidt , Kejie Fang

Single photons are an important prerequisite for a broad spectrum of quantum optical applications. We experimentally demonstrate a heralded single-photon source based on spontaneous parametric down-conversion in collinear bulk optics, and…

The efficiency of a Bell-state measurement on photon pairs is bound to 50\,\% due to the number of Bell states that can be distinguished using linear optics. Here we present the implementation of a protocol that allows us to distinguish all…

Bell state measurements, which project bipartite qubit systems onto the maximally entangled Bell basis, are central to a wide range of quantum information processing tasks, including quantum teleportation, entanglement swapping, and…

Quantum Physics · Physics 2026-04-27 Luca Bianchi , Carlo Marconi , Davide Bacco

We emphasize the Bell state analyzer, a beamsplitter, as an efficient means of detecting two-photon polarization entanglement. Whereas the optimal entanglement witness for spatially separated photons requires coordinated measurement in…

Quantum Physics · Physics 2015-07-14 Brian P. Williams , Travis S. Humble

Attenuated laser pulses are often employed in place for single photons in order to test the efficiency of the elements of a quantum network. In this work we analyse theoretically the dynamics of storage of an attenuated light pulse (where…

Quantum Physics · Physics 2019-11-11 Luigi Giannelli , Tom Schmit , Giovanna Morigi

Despite well-established no-go theorems on a perfect linear optical Bell state analyzer, we find a numerical trend that appears to approach a near-perfect measurement if we incorporate eight or more un-entangled ancilla photons into our…

Quantum Physics · Physics 2018-03-01 Jake A. Smith , Lev Kaplan

A linear 50/50 beamsplitter, together with a coincidence measurement, has been widely used in quantum optical experiments, such as teleportation, dense coding, etc., for interferometrically distinguishing, measuring, or projecting onto one…

Quantum Physics · Physics 2009-11-10 Yoon-Ho Kim , Warren P. Grice

Quantum key distribution is a key application of quantum mechanics, shaping the future of privacy and secure communications. Many protocols require single photons, often approximated by strongly attenuated laser pulses. Here, we harness the…

Bell state measurement (BSM) plays crucial roles in photonic quantum information processing. The standard linear optical BSM is based on Hong-Ou-Mandel interference where two photons meet and interfere at a beamsplitter (BS). However, a…

Quantum Physics · Physics 2018-11-20 Yong-Su Kim , Tanumoy Pramanik , Young-Wook Cho , Ming Yang , Sang-Wook Han , Sang-Yun Lee , Sung Moon

Signal state preparation in quantum key distribution schemes can be realized using either an active or a passive source. Passive sources might be valuable in some scenarios; for instance, in those experimental setups operating at high…

Quantum Physics · Physics 2020-07-22 Marcos Curty , Marc Jofre , Valerio Pruneri , Morgan W. Mitchell

Bell state measurements (BSM) play a significant role in quantum information and quantum computing, in particular, in fusion-based quantum computing (FBQC). The FBQC model is a framework for universal quantum computing provided that we are…

Quantum Physics · Physics 2024-09-10 Aleksandr Melkozerov , Ashot Avanesov , Ivan Dyakonov , Stanislav Straupe