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:1705.01670

Qubit-loss-free fusion of W states employing weak cross-Kerr nonlinearities

Mei-Yu Wang, Quanzhi Hao, Fengli Yan, Ting Gao

Published May 4, 2017• 2 citations
arXivHTMLPDF

Abstract

With the assistance of weak cross-Kerr nonlinearities, we introduce an optical scheme to fuse two small-size polarization entangled W states into a large-scale W state without qubit loss, i.e.,$\mathrm{W}_{n+m}$ state can be generated from an $n$-qubit W state and a $m$-qubit W state. To complete the fusion task, two polarization entanglement processes and one spatial entanglement process are applied. The fulfillments of the above processes are contributed by a cross-Kerr nonlinear interaction between the signal photons and a coherent state via Kerr media. We analyze the resource cost and the success probability of the scheme. There is no complete failure output in our fusion mechanism, and all the garbage states are recyclable. In addition, there is no need for any controlled quantum gate and any ancillary photon, so it is simple and feasible under the current experiment technology.

DOI
10.48550/arxiv.1705.01670

Related papers

Qubit-loss-free fusion of W states

Mei-Yu Wang, Quanzhi Hao, Fengli Yan +1 more

With the assistance of weak cross-Kerr nonlinearities, we introduce an optical scheme to fuse two small-size polarization entangled photonic W states into a large-scale W state without qubit loss, i.e.,Wn+m state can be generated from an n-qubit W state and a m-qubit W state. To complete the fusion task, two polarization entanglement processes and one spatial entanglement process are applied. The fulfillments of the above processes are contributed by a cross-Kerr nonlinear interaction between the signal photons and a coherent state via Kerr media. We analyze the resource cost and the success probability of the scheme. There is no complete failure output in our fusion mechanism, and all the remaining states are recyclable. In addition, there is no need for any controlled quantum gate and any ancillary photon, so this fusion scheme may be implemented with current experimental techniques.

Quantum Information and Computation•Feb 1, 2018•2 citations

Simultaneous qubit-loss-free fusion of three multiple W states

Meiyu Wang, Quanzhi Hao, Fengli Yan +1 more

Abstract Qubit-loss-free fusion for two W states introduced by Li K et al (2016 Phys. Rev . A 94 062315) clearly increases the final size of the obtained W state and greatly reduces the number of fusion steps to achieve a W state of a target size. Motivated by this idea, we propose a qubit-loss-free fusion scheme for fusing three polarization entangled W states simultaneously. The elements of a two-outcome positive-operator valued measurement and the appropriate joint unitary operation for realizing a positive-operator valued measurement measurement are given. As an example, with the assistance of weak cross-Kerr nonlinearities, an optical setup for fusing three W states is proposed. We analyze the success probability of the scheme and the resource cost of the present scheme, as compared to previous work.

Laser Physics Letters•Mar 14, 2018•6 citations

Fusion of W -like states in optical system

Ke Li, Ming Yang, Qing Yang +1 more

Abstract An effective scheme is proposed for preparing large-scale maximally entangled W states by fusing arbitrary-size polarization entangled W or W -like states via polarization-dependent beam splitter (PDBS). In our scheme, W m + n −1 state can be generated from an n -qubit W state and an m -qubit W state, and W m + n + t −2 state can be generated from W m , W n and W t states. The fusion process can start with Bell states too. Because PDBS has selective transmission rates for different polarization states, our fusion has a distinct property, i.e. a large-scale maximally entangled W state can be generated by fusing small-size W -like states, and the cost analyses indicate that our fusion scheme is more efficient than the previous one in fusing W -like states. In addition, there is no need for any controlled quantum gate and any ancillary photon in our scheme, so it is simple and feasible.

Laser Physics•Jan 12, 2016•6 citations

Effective schemes for fusion of hyperentangled W states

Wen-Xiu Zhang, Wen-Qiang Liu, Hai-Rui Wei

Hyperentangled states are fascinating resources in quantum information processing as they can significantly increase the channel capacity and enhance noise resistance. We explore a hyperfusion mechanism to fuse one n photon hyper-W state and one m-photon hyper-W state into a large-scale (n+m-2)-photon hyper-W state. Another mechanism to fuse one n-photon hyper-W state, one m-photon hyper-$W$ state, and one $t$-photon hyper-W state into an (n+m+t-3)-photon hyper-W state is also proposed. These two hyperfusion mechanisms are constructed employing only polarizing beam splitters, balanced beam splitters, half-wave plates, single-photon detectors, and cross-Kerr nonlinearities. Conditional quantum gates, path couplers, and ancillary photons are not required in our constructions. Moreover, our fused $W$ states are hyperentangled in the polarization and spatial degrees of freedom of single-photon systems. The presence of only one garbage output state demonstrates that high efficiency can be achieved in our schemes.

quant-pharXiv:2604.10880•Apr 14, 2026•0 citations

Qubit-loss-free fusion of W states

Ke Li, Fan‐Zhen Kong, Ming Yang +2 more

Fusion technique plays a key role in the preparation of large-scale $W$ states, but the currently existing fusion schemes are suffering from the qubit loss problem, i.e., the number of the output entangled qubits is smaller than the sum of numbers of the input entangled qubits, which will inevitably decrease the fusion efficiency and increase the number of fusion steps as well as the requirement of quantum memories. In this paper, we design a fusion mechanism to fuse two small-size $W$ states into a large-scale $W$ state without qubit loss, and thus we call it qubit-loss-free (QLF) fusion mechanism. This QLF fusion mechanism is based on a two-outcome positive-operator valued measurement on two qubits extracting from two small-size $W$ states, and works for both pure and mixed $W$ states. The QLF nature of this fusion mechanism clearly increases the final size of the obtained $W$ state, and greatly reduces the number of fusion steps as well as the requirement of quantum memories required to achieve a $W$ state of a target size, so it is more efficient and feasible than the currently existing fusion schemes. There is no complete failure output in our QLF fusion scheme, and all the garbage states are recyclable. Two example schemes are proposed to realize this QLF fusion mechanism in a cavity quantum electrodynamics system and three-qubit Heisenberg XYZ model, respectively, which demonstrates the possibility of the physical realization of this QLF fusion mechanism.

Physical Review A•Dec 13, 2016•28 citations

Preparation of four-photon polarization-entangled decoherence-free states employing weak cross-Kerr nonlinearities

Xiao‐Ming Xiu, Qingyang Li, Yan-Fang Lin +3 more

With the assistance of weak cross-Kerr nonlinearities, we present a preparation scheme of four-photon polarization-entangled decoherence-free states, which can be used to construct the minimal optical decoherence-free subspaces where a logical qubit is fully protected against collective decoherence. To complete the preparation task, one spatial entanglement process, two polarization entanglement processes, and one detecting process are applied. The fulfillments of the above processes are contributed by a cross-Kerr nonlinear interaction between the signal photons and a coherent state via Kerr media. Exploiting the available single-photon resource and simple linear optics elements, this scheme is feasible and desirable to be extended to the construction of multiphoton decoherence-free states against the collective decoherence.

Physical Review A•Oct 14, 2016•36 citations
With the assistance of weak cross-Kerr nonlinearities, we introduce an optical scheme to fuse two small-size polarization entangled W states into a large-scale W state without qubit loss, i.e.,Wn+m\mathrm{W}_{n+m}Wn+m​ state can be generated from an nnn-qubit W state and a mmm-qubit W state. To complete the fusion task, two polarization entanglement processes and one spatial entanglement process are applied. The fulfillments of the above processes are contributed by a cross-Kerr nonlinear interaction between the signal photons and a coherent state via Kerr media. We analyze the resource cost and the success probability of the scheme. There is no complete failure output in our fusion mechanism, and all the garbage states are recyclable. In addition, there is no need for any controlled quantum gate and any ancillary photon, so it is simple and feasible under the current experiment technology.
With the assistance of weak cross-Kerr nonlinearities, we introduce an optical scheme to fuse two small-size polarization entangled photonic W states into a large-scale W state without qubit loss, i.e.,Wn+m state can be generated from an n-qubit W state and a m-qubit W state. To complete the fusion task, two polarization entanglement processes and one spatial entanglement process are applied. The fulfillments of the above processes are contributed by a cross-Kerr nonlinear interaction between the signal photons and a coherent state via Kerr media. We analyze the resource cost and the success probability of the scheme. There is no complete failure output in our fusion mechanism, and all the remaining states are recyclable. In addition, there is no need for any controlled quantum gate and any ancillary photon, so this fusion scheme may be implemented with current experimental techniques.
Abstract Qubit-loss-free fusion for two W states introduced by Li K et al (2016 Phys. Rev . A 94 062315) clearly increases the final size of the obtained W state and greatly reduces the number of fusion steps to achieve a W state of a target size. Motivated by this idea, we propose a qubit-loss-free fusion scheme for fusing three polarization entangled W states simultaneously. The elements of a two-outcome positive-operator valued measurement and the appropriate joint unitary operation for realizing a positive-operator valued measurement measurement are given. As an example, with the assistance of weak cross-Kerr nonlinearities, an optical setup for fusing three W states is proposed. We analyze the success probability of the scheme and the resource cost of the present scheme, as compared to previous work.
Abstract An effective scheme is proposed for preparing large-scale maximally entangled W states by fusing arbitrary-size polarization entangled W or W -like states via polarization-dependent beam splitter (PDBS). In our scheme, W m + n −1 state can be generated from an n -qubit W state and an m -qubit W state, and W m + n + t −2 state can be generated from W m , W n and W t states. The fusion process can start with Bell states too. Because PDBS has selective transmission rates for different polarization states, our fusion has a distinct property, i.e. a large-scale maximally entangled W state can be generated by fusing small-size W -like states, and the cost analyses indicate that our fusion scheme is more efficient than the previous one in fusing W -like states. In addition, there is no need for any controlled quantum gate and any ancillary photon in our scheme, so it is simple and feasible.
Hyperentangled states are fascinating resources in quantum information processing as they can significantly increase the channel capacity and enhance noise resistance. We explore a hyperfusion mechanism to fuse one n photon hyper-W state and one m-photon hyper-W state into a large-scale (n+m-2)-photon hyper-W state. Another mechanism to fuse one n-photon hyper-W state, one m-photon hyper-WWW state, and one ttt-photon hyper-W state into an (n+m+t-3)-photon hyper-W state is also proposed. These two hyperfusion mechanisms are constructed employing only polarizing beam splitters, balanced beam splitters, half-wave plates, single-photon detectors, and cross-Kerr nonlinearities. Conditional quantum gates, path couplers, and ancillary photons are not required in our constructions. Moreover, our fused WWW states are hyperentangled in the polarization and spatial degrees of freedom of single-photon systems. The presence of only one garbage output state demonstrates that high efficiency can be achieved in our schemes.
Fusion technique plays a key role in the preparation of large-scale WWW states, but the currently existing fusion schemes are suffering from the qubit loss problem, i.e., the number of the output entangled qubits is smaller than the sum of numbers of the input entangled qubits, which will inevitably decrease the fusion efficiency and increase the number of fusion steps as well as the requirement of quantum memories. In this paper, we design a fusion mechanism to fuse two small-size WWW states into a large-scale WWW state without qubit loss, and thus we call it qubit-loss-free (QLF) fusion mechanism. This QLF fusion mechanism is based on a two-outcome positive-operator valued measurement on two qubits extracting from two small-size WWW states, and works for both pure and mixed WWW states. The QLF nature of this fusion mechanism clearly increases the final size of the obtained WWW state, and greatly reduces the number of fusion steps as well as the requirement of quantum memories required to achieve a WWW state of a target size, so it is more efficient and feasible than the currently existing fusion schemes. There is no complete failure output in our QLF fusion scheme, and all the garbage states are recyclable. Two example schemes are proposed to realize this QLF fusion mechanism in a cavity quantum electrodynamics system and three-qubit Heisenberg XYZ model, respectively, which demonstrates the possibility of the physical realization of this QLF fusion mechanism.
With the assistance of weak cross-Kerr nonlinearities, we present a preparation scheme of four-photon polarization-entangled decoherence-free states, which can be used to construct the minimal optical decoherence-free subspaces where a logical qubit is fully protected against collective decoherence. To complete the preparation task, one spatial entanglement process, two polarization entanglement processes, and one detecting process are applied. The fulfillments of the above processes are contributed by a cross-Kerr nonlinear interaction between the signal photons and a coherent state via Kerr media. Exploiting the available single-photon resource and simple linear optics elements, this scheme is feasible and desirable to be extended to the construction of multiphoton decoherence-free states against the collective decoherence.