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Aiming the construction of quantum computers and quantum communication systems based on optical devices, in this work we present possible implementations of quantum and classical CNOTs gates, as well an optical setup for generation and…

Quantum Physics · Physics 2007-05-23 Joao Batista Rosa Silva , Rubens Viana Ramos

We show how to construct a near deterministic CNOT using several single photons sources, linear optics, photon number resolving quantum non-demolition detectors and feed-forward. This gate does not require the use of massively entangled…

Quantum Physics · Physics 2009-11-10 Kae Nemoto , W. J. Munro

It is known that unambiguous discrimination among non-orthogonal but linearly independent quantum states is possible with a certain probability of success. Here, we consider a variant of that problem. Instead of discriminating among all of…

Quantum Physics · Physics 2009-11-07 Yuqing Sun , Janos A. Bergou , Mark Hillery

The discrimination of any pair of unknown quantum states is performed by devices processing three parts of inputs: copies of the pair of unknown states we want to discriminate are respectively stored in two program systems and copies of…

Quantum Physics · Physics 2016-08-16 Bing He , János A. Bergou

We propose probabilistic controlled-NOT and controlled-phase gates for qubits stored in the polarization of photons. The gates are composed of linear optics and photon detectors, and consume polarization entangled photon pairs. The fraction…

Quantum Physics · Physics 2009-11-07 Masato Koashi , Takashi Yamamoto , Nobuyuki Imoto

Two photons in free space pass each other undisturbed. This is ideal for the faithful transmission of information, but prohibits an interaction between the photons as required for a plethora of applications in optical quantum information…

Quantum Physics · Physics 2017-02-17 Bastian Hacker , Stephan Welte , Gerhard Rempe , Stephan Ritter

Determining an unknown quantum state from an ensemble of identical systems is a fundamental, yet experimentally demanding, task in quantum science. Here we study the number of measurement bases needed to fully characterize an arbitrary…

Quantum Physics · Physics 2019-02-11 Leonardo Banchi , W. Steven Kolthammer , M. S. Kim

We propose an optical scheme to build an entangled network composed of W state based on polarization encoded qubits (photons). This new setup consists of 2 cNOT gates, 4 V gates, 2 Hadamard gates and basic optical tools such as polarizing…

Quantum Physics · Physics 2026-05-29 Firat Diker , Can Yesilyurt

The quest for the realization of effective quantum state discrimination strategies is of great interest for quantum information technology, as well as for fundamental studies. Therefore, it is crucial to develop new and more efficient…

We experimentally realize a nonlinear quantum protocol on single-photon qubits with linear optical elements and appropriate measurements. The quantum nonlinearity is induced by post-selecting the polarization qubit based on a measurement…

Quantum Physics · Physics 2019-11-13 Gaoyan Zhu , Orsolya Kalman , Kunkun Wang , Lei Xiao , Dengke Qu , Xiang Zhan , Zhihao Bian , Tamas Kiss , Peng Xue

We present an experimental platform for linear-optical quantum information processing. Our setup utilizes multiphoton generation using a high-quality single-photon source, which is demultiplexed across multiple spatial channels, a…

The discrimination of non-orthogonal quantum states with reduced or without errors is a fundamental task in quantum measurement theory. In this work, we investigate a quantum measurement strategy capable of discriminating two coherent…

Quantum Physics · Physics 2010-10-12 Christoffer Wittmann , Ulrik L. Andersen , Gerd Leuchs

Photonic quantum computing has recently emerged as a promising candidate for fault-tolerant quantum computing by photonic qubits. These protocols make use of nondeterministic gates, enabling universal quantum computation. However, the…

Quantum Physics · Physics 2024-07-11 Csaba Czabán , Zoltán Kolarovszki , Márton Karácsony , Zoltán Zimborás

We propose an optimal discrimination scheme for a case of four linearly independent nonorthogonal symmetric quantum states, based on linear optics only. The probability of discrimination is in agreement with the optimal probability for…

Quantum Physics · Physics 2009-11-13 O. Jiménez , X. Sánchez-Lozano , A. Delgado , C. Saavedra

We propose a probabilistic quantum protocol to realize a nonlinear transformation of qutrit states, which by iterative applications on ensembles can be used to distinguish two types of pure states. The protocol involves single-qutrit and…

Quantum Physics · Physics 2018-11-20 P. V. Pyshkin , A. Gábris , O. Kálmán , I. Jex , T. Kiss

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

We discuss a state discriminator that unambiguously distinguishes between two quantum registers prepared with multiple copies of two unknown qubits. This device achieves the optimal performance by von Neumann measurement and general POVM in…

Quantum Physics · Physics 2016-10-31 Bing He , Janos A. Bergou

Efficient teleportation is a crucial step for quantum computation and quantum networking. In the case of qubits, four different entangled Bell states have to be distinguished. We have realized a probabilistic, but in principle…

Quantum Physics · Physics 2009-11-10 Philip Walther , Anton Zeilinger

In this paper a programmable quantum state discriminator is implemented by using nuclear magnetic resonance. We use a two qubit spin-1/2 system, one for the data qubit and one for the ancilla (programme) qubit. This device does the…

Quantum Physics · Physics 2009-11-11 T. Gopinath , Ranabir Das , Anil Kumar

We propose a non-deterministic CNOT gate based on a quantum cloner, a quantum switch based on all optical routing of single photon by single photon, a quantum-dot spin in a double-sided optical microcavity with two photonic qubits, delay…

Quantum Physics · Physics 2019-06-18 Amor Gueddana , Peyman Gholami , Vasudevan Lakshminarayanan