Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:0810.2850 · New Journal of Physics

Local expansion of photonic W state using a polarization-dependent beamsplitter

Toshiyuki Tashima, Şahin Kaya Özdemir, Takashi Yamamoto, Masato Koashi, Nobuyuki Imoto

Published Feb 11, 2009• 76 citations
arXivHTMLPDF

Abstract

We propose a simple probabilistic optical gate to expand polarization entangled W states. The gate uses one polarization-dependent beamsplitter and a horizontally polarized single photon as an ancilla. The gate post-selectively expands N -photon W states to ( N +1)-photon W states. A feasibility analysis considering the realistic experimental conditions shows that the scheme is within the reach of the current quantum optical technologies.

DOI
10.1088/1367-2630/11/2/023024

Related papers

A simple scheme for expanding a polarization-entangledWstate by adding one photon

Yan-Xiao Gong, Xu‐Bo Zou, Yun‐Feng Huang +1 more

We propose a simple scheme for expanding a polarization-entangled W state. By mixing a single photon and one of the photons in an n -photon W state at a polarization-dependent beam splitter (PDBS), we can obtain an ( n + 1)-photon W state after post-selection. Our scheme also opens the door to generating n -photon W states using single photons and linear optics.

arXiv:0810.2705•Journal of Physics B Atomic Molecular and Optical Physics•Jan 21, 2009•11 citations

Elementary optical gate for expanding an entanglement web

Toshiyuki Tashima, Şahin Kaya Özdemir, Takashi Yamamoto +2 more

We introduce an elementary optical gate for expanding polarization entangled $W$ states in which every pair of photons is entangled alike. The gate is composed of a pair of 50:50 beamsplitters and ancillary photons in the two-photon Fock state. By seeding one of the photons in an $n$-photon $W$ state into this gate, we obtain an $(n+2)$-photon $W$ state after postselection. This gate gives a better efficiency and a simpler implementation than previous proposals for $W$-state preparation.

arXiv:0803.1897•Physical Review A•Mar 25, 2008•90 citations

Optimal local expansion of W states using linear optics and Fock states

Rikizo Ikuta, Toshiyuki Tashima, Takashi Yamamoto +2 more

We derive the maximum success probability of circuits with passive linear optics for postselectively expanding an $N$-photon $W$ state to an $(N+n)$-photon $W$ state, by accessing only one photon of the initial $W$ state and adding $n$ photons in a Fock state. We show that the maximum success probability is achieved by a polarization-dependent beamsplitter and $n\ensuremath{-}1$ polarization-independent beamsplitters.

arXiv:1004.0608•Physical Review A•Jan 24, 2011•33 citations

Deterministic generation of a four-qubit W state using one- and two-qubit gates

Fırat Diker, Can Yesilyurt

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 beamsplitters (PBSs) and path couplers (PCs). V gate is a specially-designed tool acting as a two-qubit gate which is composed of a cNOT gate, 3 PBSs and a PC. By using this gate, one benefits from the temporarily generated optical degree of freedom, which is the spatial mode of a photon in the proposed scheme. Using an extra degree of freedom allows us to perform more capable processing for W-state creation protocols. We use four photons as input, which means we do not need entanglement as a resource. Also, we show that the proposed scheme can be implemented by operating the quantum optical gates which can be realized via current photonics technology. Additionally, we provide discussions of quantum contextuality and non-locality for W states.

arXiv:1704.08204•Apr 25, 2017•0 citations

Probabilistic quantum logic operations using polarizing beam splitters

T. B. Pittman, B. C. Jacobs, J. D. Franson

It has previously been shown that probabilistic quantum logic operations may be performed using linear optical elements, additional photons (ancilla), and post-selection based on the output of single-photon detectors. Here we describe the operation of several quantum logic operations of an elementary nature, including a quantum parity check and a quantum encoder, and we show how they may be combined to implement a controlled-NOT (CNOT) gate. All of these gates may be constructed using polarizing beam splitters that completely transmit one state of polarization and totally reflect the orthogonal state of polarization, which allows a simple explanation of each operation. We also describe a polarizing beam splitter implementation of a CNOT gate that is closely analogous to the quantum teleportation technique previously suggested by Gottesman and Chuang [Nature 402, 390 (1999)]. Finally, our approach has the interesting feature that it makes practical use of a quantum-eraser technique.

arXiv:quant-ph/0107091•Physical Review A•Nov 16, 2001•434 citations

Deterministic linear-optical quantum control gates utilizing path and polarization degrees of freedom

Hongyi Meng

We present a general scheme for a family of linear-optical quantum control gates, including controlled-not and controlled-swap gates for two or three qubits. Our approach utilizes polarization-path-entangled pairs of photons and encodes qubits in mixed degrees of freedom with the control qubit specifically occupying the polarization degree of freedom. By exploiting multiple degrees of freedom and initial state entanglement of the two photons, the proposed control gates do not require any ancilla photons or measurement-induced nonlinearities. Since our gates are purely linear and we implicitly use nonlinearities in a standard manner to create entanglement via parametric nonlinear process, our work demonstrates that a need to have nonlinearities in the photonic gates can be shifted to the state preparation stage; the cost of such shift is that the construction of a certain class of single-qubit operations, such as Hadamard, needs to be probabilistic. In particular, we focus on a deterministic linear-optical quantum Fredkin (controlled-swap) gate and perform a full characterization of the gate performance with a high fidelity typically well above $99%$ under realistic conditions. The proposed control gates rely on simple linear-optical elements and polarization-entangled photon pairs readily generated from ubiquitous sources, making the gates experimentally feasible with current technologies.

Physical Review A•Mar 10, 2022•22 citations
We propose a simple probabilistic optical gate to expand polarization entangled W states. The gate uses one polarization-dependent beamsplitter and a horizontally polarized single photon as an ancilla. The gate post-selectively expands N -photon W states to ( N +1)-photon W states. A feasibility analysis considering the realistic experimental conditions shows that the scheme is within the reach of the current quantum optical technologies.
We introduce an elementary optical gate for expanding polarization entangled WWW states in which every pair of photons is entangled alike. The gate is composed of a pair of 50:50 beamsplitters and ancillary photons in the two-photon Fock state. By seeding one of the photons in an nnn-photon WWW state into this gate, we obtain an (n+2)(n+2)(n+2)-photon WWW state after postselection. This gate gives a better efficiency and a simpler implementation than previous proposals for WWW-state preparation.
We derive the maximum success probability of circuits with passive linear optics for postselectively expanding an NNN-photon WWW state to an (N+n)(N+n)(N+n)-photon WWW state, by accessing only one photon of the initial WWW state and adding nnn photons in a Fock state. We show that the maximum success probability is achieved by a polarization-dependent beamsplitter and $n\ensuremath{-}1$ polarization-independent beamsplitters.
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 beamsplitters (PBSs) and path couplers (PCs). V gate is a specially-designed tool acting as a two-qubit gate which is composed of a cNOT gate, 3 PBSs and a PC. By using this gate, one benefits from the temporarily generated optical degree of freedom, which is the spatial mode of a photon in the proposed scheme. Using an extra degree of freedom allows us to perform more capable processing for W-state creation protocols. We use four photons as input, which means we do not need entanglement as a resource. Also, we show that the proposed scheme can be implemented by operating the quantum optical gates which can be realized via current photonics technology. Additionally, we provide discussions of quantum contextuality and non-locality for W states.
It has previously been shown that probabilistic quantum logic operations may be performed using linear optical elements, additional photons (ancilla), and post-selection based on the output of single-photon detectors. Here we describe the operation of several quantum logic operations of an elementary nature, including a quantum parity check and a quantum encoder, and we show how they may be combined to implement a controlled-NOT (CNOT) gate. All of these gates may be constructed using polarizing beam splitters that completely transmit one state of polarization and totally reflect the orthogonal state of polarization, which allows a simple explanation of each operation. We also describe a polarizing beam splitter implementation of a CNOT gate that is closely analogous to the quantum teleportation technique previously suggested by Gottesman and Chuang [Nature 402, 390 (1999)]. Finally, our approach has the interesting feature that it makes practical use of a quantum-eraser technique.
We present a general scheme for a family of linear-optical quantum control gates, including controlled-not and controlled-swap gates for two or three qubits. Our approach utilizes polarization-path-entangled pairs of photons and encodes qubits in mixed degrees of freedom with the control qubit specifically occupying the polarization degree of freedom. By exploiting multiple degrees of freedom and initial state entanglement of the two photons, the proposed control gates do not require any ancilla photons or measurement-induced nonlinearities. Since our gates are purely linear and we implicitly use nonlinearities in a standard manner to create entanglement via parametric nonlinear process, our work demonstrates that a need to have nonlinearities in the photonic gates can be shifted to the state preparation stage; the cost of such shift is that the construction of a certain class of single-qubit operations, such as Hadamard, needs to be probabilistic. In particular, we focus on a deterministic linear-optical quantum Fredkin (controlled-swap) gate and perform a full characterization of the gate performance with a high fidelity typically well above 9999%99 under realistic conditions. The proposed control gates rely on simple linear-optical elements and polarization-entangled photon pairs readily generated from ubiquitous sources, making the gates experimentally feasible with current technologies.