Demonstrating multipartite entanglement of single-particleWstates: Linear optical schemes (original) (raw)
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Physical Review Letters, 2000
We show that one single-mode squeezed state distributed among N parties using linear optics suffices to produce a truly N-partite entangled state for any nonzero squeezing and arbitrarily many parties. From this N-partite entangled state, via quadrature measurements of N 2 2 modes, bipartite entanglement between any two of the N parties can be "distilled," which enables quantum teleportation with an experimentally determinable fidelity better than could be achieved in any classical scheme.
Characterization of Multipartite Entanglement for One Photon Shared Among Four Optical Modes
Science, 2009
Entanglement Sharing Quantum information processing relies on the ability to generate quantum states, to entangle them, and to send and receive those quantum states reliably across networks. With quantum two-level systems, or qubits, if you want to have a large system (and solve complex problems), there is a fear that the ancillary equipment required to control the system will increase rapidly, perhaps too quickly. The use of multipartite systems, where several quantum states can be accessed in a single component, has been proposed as a solution. Papp et al. (p. 764 ) work with a multipartite system consisting of a single photon shared between four optical modes and show that the degree of entanglement can be controllably tuned. The ability to work with, and control, such entangled multipartite systems should help the development of quantum information processing.
Physical Review A, 2015
It is well known that the efficiency of linear optical implementations of the dense coding is limited by one's ability to discriminate between the four optically encoded Bell states.The best experimental demonstration up to date reports the transmission of ≈ 1.63 bits of information per single optical qubit which is less than the theoretical bound of 2.0 bits for a generic qubit. We show that besides the Bell states there is a class of bipartite two-photon entangled states that can also facilitate dense coding. However, in contrast to the Bell states, they can be deterministically discriminated by means of linear optics and coincidence photo detection without using any auxiliary entanglement resources. We discuss how the proposed dense coding scheme can be generalized to the case of two-photon N -mode entangled states for N = 6, 8.
Teleportation of entangled states without Bell-state measurement
Physical Review A, 2005
In a recent paper ͓Phys. Rev. A 70, 025803 ͑2004͔͒ we presented a scheme to teleport an entanglement of zero-and one-photon states from a bimodal cavity to another one, with 100% success probability. Here, inspired by recent results in the literature, we have modified our previous proposal to teleport the same entangled state without using Bell-state measurements. For comparison, the time spent, the fidelity, and the success probability for this teleportation are considered.
Quantum teleportation and Bell's inequality using single-particle entanglement
Physical Review A, 2001
A single-particle entangled state can be generated by illuminating a beam splitter with a single photon. Quantum teleportation utilizing such a single-particle entangled state can be successfully achieved with a simple setup consisting only of linear optical devices such as beam splitters and phase shifters. Application of the locality assumption to a single-particle entangled state leads to Bell's inequality, a violation of which signifies the nonlocal nature of a single particle.
Broadcasting of entanglement at a distance using linear optics and telecloning of entanglement
Physical Review A, 2005
We propose a scheme for broadcasting of entanglement at a distance based on linear optics. We show that an initial polarization entangled state can be simultaneously split and transmitted to a pair of observers situated at different locations with the help of two conditional Bell-state analyzers based on two beam splitters characterized by the same reflectivity R. In particular for R = 1/3 the final states coincide with the output states obtained by the broadcasting protocol proposed by Buzek et al. [Phys. Rev. A 55, 3327 (1997)]. Further we present a different protocol called telecloning of entanglement, which combines the many-to-many teleportation and nonlocal optimal asymmetric cloning of an arbitrary entangled state. This scheme allows the optimal transmission of the two nonlocal optimal clones of an entangled state to two pairs of spatially separated receivers.
Purification of Single-Photon Entanglement
Physical Review Letters, 2010
Single-photon entanglement is a simple form of entanglement that exists between two spatial modes sharing a single photon. Despite its elementary form, it provides a resource as useful as polarization-entangled photons and it can be used for quantum teleportation and entanglement swapping operations. Here, we report the first experiment where single-photon entanglement is purified with a simple linear-optics based protocol. Besides its conceptual interest, this result might find applications in long distance quantum communication based on quantum repeaters.
Witnessing Trustworthy Single-Photon Entanglement with Local Homodyne Measurements
Physical Review Letters, 2013
Single-photon entangled states, i.e. states describing two optical paths sharing a single photon, constitute the simplest form of entanglement. Yet they provide a valuable resource in quantum information science. Specifically, they lie at the heart of quantum networks, as they can be used for quantum teleportation, swapped and purified with linear optics. The main drawback of such entanglement is the difficulty in measuring it. Here, we present and experimentally test an entanglement witness allowing one not only to say whether a given state is path-entangled but also that entanglement lies in the subspace where the optical paths are each filled with one photon at most, i.e. refers to single-photon entanglement. It uses local homodyning only and relies on no assumption about the Hilbert space dimension of the measured system. Our work provides a simple and trustful method for verifying the proper functioning of future quantum networks. PACS numbers: 03.65.Ud, 03.67.Mn, 42.50.Dv
Teleportation of bipartite states using a single entangled pair
Physics Letters A, 2005
A class of quantum protocols to teleport bipartite (entangled) states of two qubits is suggested. Our schemes require a single entangled pair shared by the two parties and the transmission of three bits of classical information, as well as a two-qubit gate with an additional qubit at the receiver's location. Noisy quantum channels are considered and the effects on both the teleportation fidelity and the entanglement of the replica are evaluated.
Entanglement of photons in their dual wave-particle nature
Nature communications, 2017
Wave-particle duality is the most fundamental description of the nature of a quantum object, which behaves like a classical particle or wave depending on the measurement apparatus. On the other hand, entanglement represents nonclassical correlations of composite quantum systems, being also a key resource in quantum information. Despite the very recent observations of wave-particle superposition and entanglement, whether these two fundamental traits of quantum mechanics can emerge simultaneously remains an open issue. Here we introduce and experimentally realize a scheme that deterministically generates entanglement between the wave and particle states of two photons. The elementary tool allowing this achievement is a scalable single-photon setup which can be in principle extended to generate multiphoton wave-particle entanglement. Our study reveals that photons can be entangled in their dual wave-particle behavior and opens the way to potential applications in quantum information pr...